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    • 专利摘要:
    The invention relates to a Raman spectrometry apparatus (1) comprising a source system (2) generating a first excitation light beam at a first excitation frequency, a spectral separation system (8), a detection system ( 10) in a spectral observation interval and a calculator (12) generating a first Raman scattering spectrum portion in a first Raman spectral domain extending between a first relative wave number and a second relative wave number. According to the invention, the source system is adapted to generate a second excitation light beam at a second excitation frequency different from the first excitation frequency, the computer generating a second portion of the Raman scattering spectrum in a second Raman spectral domain in wavenumber function of the same spectral observation interval, said second spectral domain extending between a third relative wave number and a fourth relative wave number. The invention also relates to a method of Raman spectrometry.
    公开号:FR3081221A1
    申请号:FR1854096
    申请日:2018-05-16
    公开日:2019-11-22
    发明作者:Nicolas Daugey；Thierry Buffeteau；Jean-Luc Bruneel；Vincent Rodriguez
    申请人:Centre National de la Recherche Scientifique CNRS；Universite de Bordeaux；Institut Polytechnique de Bordeaux；
    IPC主号:
    专利说明:

    Technical field to which the invention relates
    The present invention relates generally to the field of Raman spectrometry.
    It relates more particularly to an apparatus and a method of Raman spectrometry.
    TECHNOLOGICAL BACKGROUND
    The observation of spectral domains towards high wave numbers by Raman spectrometry (we speak of Raman spectrometry at high frequencies) generally requires adjustments involving moving the optical components or the use of other optical components, or according to the case, more suitable detection systems increasing the complexity and therefore the cost of the device. These conventional Raman spectrometry systems are generally limited in spectral resolution and / or in the spectral domains observed.
    According to known devices, it is possible to obtain good spectral resolution by restricting the spectral range. The use of a spectrometer with a mobile dispersive system then makes it possible to successively probe the entire spectral range. In general, this configuration induces a decrease in detectivity of the detection system at very high wave numbers (greater than 4000 cm -1 ).
    Another known configuration consists in choosing a fixed spectral separation system for the entire spectral range but with a lower spectral resolution.
    Yet another configuration consists in using a mask comprising a set of slots in front of the detection system to refine the resolution, and to successively shift this mask to resolve the spectrum over the entire spectral range.
    This technology applies to a Raman spectrometry device, for which it is desirable to extend the spectral range and / or to increase the spectral resolution, while maintaining the compactness, the simplicity and consequently its cost and its robustness but also its reproducibility.
    Object of the invention
    In order to overcome the aforementioned drawbacks of the prior art, the present invention provides a Raman spectrometry apparatus.
    More particularly, according to the invention, a Raman spectrometry apparatus is proposed for characterizing a sample, the apparatus comprising a source system generating a first incident excitation light beam at a first excitation wavelength, a system of spectral separation receiving a first scattered light beam formed by scattering of said first excitation incident light beam on the sample and spectrally separating said first scattered light beam, a detection system making it possible to record a first Raman signal associated with said first scattered light beam and detected in a spectral wavelength observation interval extending between a first observation wavelength and a second observation wavelength, a computer receiving the first Raman signal from said detection system and generating a first part of the Raman spectrum in function tion of the Raman displacement in a first Raman spectral domain in relative wave number, said first Raman spectral domain extending between a first relative wave number function of the first excitation wavelength and of the first length d observation wave and a second relative wave number depending on the first excitation wavelength and the second observation wavelength.
    According to the invention, said source system is adapted to generate at least one second incident excitation light beam at a second excitation wavelength, said second excitation wavelength being different from the first length d excitation wave, said spectral separation system being adapted to receive a second scattered light beam formed by scattering of said second incident excitation light beam on the sample and to spectrally separate said second scattered light beam, said detection system being adapted to detect and record a second Raman signal associated with said second light beam scattered in the same spectral wavelength observation interval, said computer being adapted to measure the second Raman signal and to generate a second part of the Raman spectrum as a function of Raman displacement in a second domai spectral Raman in relative wave number, said second spectral domain Raman extending between a third relative wave number which is a function of the second excitation wavelength and of the first observation wavelength and a fourth relative wavenumber as a function of the second excitation wavelength and the second observation wavelength.
    Advantageously, in the configuration of the invention, different excitation wavelengths are used in combination without modifying the detection filter or filters. A relatively narrow spectral observation interval then makes it possible to obtain as many different parts of the Raman spectrum over different spectral domains in relative wavelength as of excitation wavelengths, then allowing the reconstruction of an extended Raman spectrum. . The compactness of the spectrometry device and its simplified use are then improved because only the excitation wavelengths are modified, no additional adjustment is necessary.
    Other non-limiting and advantageous characteristics of the Raman spectrometry device according to the invention, taken individually or in any technically possible combination, are the following:
    - the source system is adapted to generate a plurality of excitation light beams at a plurality of excitation wavelengths;
    the source system comprises a plurality of monochromatic laser sources, a laser source tunable in optical frequency and / or a source with a plurality of selectable or spatially separable monochromatic excitation wavelengths;
    - the source system comprises a continuous or pulse laser source;
    - There is also provided at least one device for polarizing the excitation light beam between the source system and the sample, said polarization device being adapted to polarize the first incident excitation light beam and, respectively, the second light beam incident of excitation following at least two states of polarization orthogonal between them;
    - There is also provided a polarization analyzer arranged between the sample and the detection system, the polarization analyzer being adapted to analyze and / or separate in polarization the first scattered light beam and, respectively, the second scattered light beam;
    - the computer is adapted to generate a first, respectively second, part of the hyper Raman scattering spectrum in a first, respectively second, spectral domain of hyper Raman displacement in relative wave number, in which the first relative wave number is equal to the difference between an integer multiple n of the first excitation wave number and the first observation wave number, the second relative wave number is equal to the difference between an integer multiple n of the first number d excitation wave and the second observation wave number, the third relative wave number is equal to the difference between an integer multiple n of the second excitation wave number and the first wave number d observation, the fourth relative wave number is equal to the difference between an integer multiple n of the second excitation wave number and the second observation wave number, the multiple integer n being greater than or equal to two;
    - There is also a detection filter configured to cut the first excitation wavelength and / or the second excitation wavelength;
    the detection filter comprises at least one high-pass filter, a low-pass filter or a band-pass filter or a combination of said filters;
    - the spectral separation system comprises a spectrometer based on diffraction grating (s), prism (s) and / or grism (s) or a spectrometer comprising a combination of diffraction grating (s) and / or phsme (s) and / or grism (s);
    - the spectral separation system comprises an interference filter and / or an interferometer;
    - the detection filter is fixed; and
    the detection system comprises a single-channel detector or a one-dimensional linear detector or a two-dimensional matrix detector.
    The invention also provides a Raman spectrometry method comprising the following steps:
    - generation of a first incident excitation light beam at a first excitation wavelength by a source system;
    - spectral separation of a first scattered light beam formed by scattering the first incident excitation light beam on a sample;
    recording of a first Raman signal associated with the first scattered light beam, detected in a spectral interval of observation in wavelength extending between a first observation wavelength and a second wavelength of observation;
    - calculation of a first part of the Raman spectrum as a function of the Raman displacement in a first Raman spectral domain in terms of relative wave number, said first Raman spectral domain extending between a first relative wave number as a function of the first length d excitation wave and the first observation wavelength and a second relative wave number function of the first excitation wavelength and the second observation wavelength;
    generation of at least one second incident excitation light beam at a second excitation wavelength by the source system, said second excitation wavelength being different from the first wavelength excitement;
    - spectral separation of a second scattered light beam formed by scattering of the second incident excitation light beam on the sample;
    - recording of a second Raman signal associated with the second scattered light beam, detected in the same spectral wavelength observation interval;
    - calculation of a second part of the Raman spectrum as a function of the Raman displacement in a second Raman spectral domain in relative wave number, said second Raman spectral domain extending between a third relative wave number depending on the second length d excitation wave and the first observation wavelength and a fourth relative wave number function of the second excitation wavelength and the second observation wavelength; and
    - Combination of said first part of the Raman scattering spectrum and of said second part of the Raman scattering spectrum to reconstruct a Raman scattering spectrum over a wide spectral domain in relative wave number and / or having an increased spectral resolution in the first and / or second Raman spectral domain.
    Detailed description of an exemplary embodiment
    The description which follows with reference to the appended drawings, given by way of nonlimiting examples, will make it clear what the invention consists of and how it can be carried out.
    In the accompanying drawings:
    - Figure 1 provides a schematic representation of the various elements of a Raman spectrometry device according to the invention;
    - Figure 2 provides an example of an instrumental configuration of the Raman spectrometry device according to the invention;
    - Figure 3 provides a schematic representation of the spectral domains obtained in relative wave number for several proposed excitation wavelengths;
    - Figure 4 shows an example of several parts of Raman scattering spectra in Stokes configuration, acquired at several excitation wavelengths and represented as a function of the observation wavelength;
    - Figure 5 shows an example of parts of Raman scattering spectrum in Stokes configuration calculated from the parts of spectra of Figure 4 and represented as a function of the Raman displacement expressed in relative wave number;
    - Figure 6 shows an example of several parts of Raman scattering spectra in anti-Stokes configuration, acquired at several excitation wavelengths and represented as a function of the observation wavelength;
    FIG. 7 represents the examples of parts of the Raman scattering spectrum in anti-Stokes configuration calculated from the parts of spectra of FIG. 6 acquired at different excitation wavelengths, and represented as a function of the Raman displacement expressed in relative wave number;
    - Figure 8 shows an example of parts of hyper Raman scattering spectrum in Stokes configuration, acquired at different excitation wavelengths and represented as a function of the observation wavelength;
    FIG. 9 represents the examples of parts of the hyper Raman scattering spectrum in the Stokes configuration calculated from the parts of spectra of FIG. 8 and represented as a function of the Raman displacement expressed in relative wave number; and
    - Figure 10 provides another schematic representation of the various elements of a Raman spectrometry device according to the invention.
    Throughout this description, the terms wavelength and number of waves will be used, the relationship between the two terms being described by the following formula (1):
    in which v corresponds to the wave number, expressed in cm ′ 1 and λ corresponds to the wavelength expressed in nm.
    The Raman effect consists of the inelastic scattering of photons by a material, a solution or a gas. In all this description, the Raman displacement or Raman shift is always expressed as a difference in wave numbers, here denoted kv Raman . Raman displacement is equal to the difference between a wavenumber corresponding to the wavelength of the incident excitation light beam and a wavenumber corresponding to a wavelength in a spectral observation interval. The Raman displacement in wave number, called in this document relative wave number, of the excitation compared to the observation, is given by the following formula:
    AŸRaman ^ exc ~ ^ obs Q 7) X 1θ (CÎTl) (2) 'A-exc ^ obs' in which the deviation or difference in wave numbers kv Raman expressed in relative wave number (in cm' 1 ), corresponds to Raman displacement or Raman shift, A exc corresponds to the excitation wavelength and A obs corresponds to a wavelength in the spectral observation interval, X exc and X obs being expressed in nm. The negative values of ^ v Raman correspond to the anti-Stokes Raman scattering and the positive values of ^ v Raman correspond to the Raman Stokes scattering.
    In the case of the hyper Raman configuration with n photons, the relative wave number is therefore formed by the difference between an integer multiple of the excitation wave number and the observation wave number: ^ v Raman = nv exc -v obs (3), with n> 2.
    We define a spectral domain in Raman displacement or in Raman offset, hereinafter called Raman spectral domain, expressed in relative wave number.
    Device and method
    Figure 1 provides a schematic representation of the elements of a Raman 1 spectrometry apparatus according to the invention.
    The Raman spectrometry apparatus 1 comprises a source system 2, an optional polarization device 4, an optional optical system 3 for guidance and / or focusing and / or collimation and / or beam shaping, a spectral separation system 8, a detection filter 9, a detection system 10 and a computer 12. The Raman spectrometry apparatus 1 is intended to characterize a sample 6.
    The source system 2 is adapted to generate an incident excitation light beam at at least one first excitation wavelength, denoted  e% Ci and at a second excitation wavelength A exCz . In an exemplary embodiment, the source system 2 comprises a plurality of monochromatic laser sources 21, 22. The first laser source 21 generates an excitation light beam at the first excitation wavelength A exC1 , _ 1θ7 corresponding has a first excitation wave number v exc = -—. The second
    Aexci laser source 22 generates an excitation light beam at the second excitation wavelength û exC2 , corresponding to a second excitation wave number _ 10 7 v exc = -—. In this case of plurality of monochromatic AexC2 laser sources, the Raman spectrometry apparatus 1 comprises a source selector or combiner 20. According to an alternative, the source system 2 comprises a laser source tunable in wavelength. According to another alternative, the source system 2 comprises a plurality of sources tunable in wavelength. According to another alternative, the source system 2 comprises a source with multiple selectable wavelengths. The source system 2 generates an incident light beam of continuous or pulsed excitation.
    As an option, the Raman spectrometry device 1 includes a polarization device 4. The polarization device 4 can be integrated into the source system 2 or separated from the source system 2. This polarization device 4 is described below, in connection with application to Raman optical activity measurement (ROA).
    Advantageously, the Raman spectrometry apparatus 1 comprises an optical system 3 for guiding and / or collimating and / or focusing and / or shaping the beam. The optical system 3 can be integrated at least in part with the source system 2 or separated from the source system 2. The incident excitation light beam is directed towards the optical system 3 for guidance and / or collimation and / or focusing and / or beam shaping. The optical system 3 is configured to direct and adapt the light beam to the sample 6.
    In practice, the optical system 3 can comprise a set of lenses and / or mirrors and / or an optical fiber and / or a set of optical fibers. Preferably, the optical fiber used is a hollow fiber which makes it possible to limit the spurious signals during the transmission of the light beam. The optical system 3 can comprise a confocal optical device with mirror and / or microscope objective.
    The incident excitation light beam at the first excitation wavelength is scattered by the sample 6 and generates a first scattered light beam. Throughout this description, the term “light beam scattered by the sample” will also take into account the case of light beams scattered regardless of the direction of observation, in particular the example of light beams backscattered by samples opaque by example. Similarly, the incident excitation light beam at the second excitation wavelength is scattered by the sample and generates a second scattered light beam.
    A collection optical system 7 can make it possible to collect the light beam diffused by the sample 6. In the case of backscattered light beams, the collection optical system 7 can be confused with the optical system 3 for guidance and / or collimation and / or focusing and shaping of the beam.
    The Raman spectrometry apparatus 1 comprises a spectral separation system 8 adapted to receive and spectrally separate the light beam scattered by the sample 6. In an exemplary embodiment, the spectral separation system 8 comprises a lattice-based spectrometer ( x) diffraction (or "diffraction grating" according to English terminology) or a spectrometer based on phsme (s) or a spectrometer based on grism (s) or a spectrometer comprising a combination of grating (x) of diffraction and / or prism (s) and / or ghsm (s). The light beam diffused by the sample 6 is thus spatially dispersed in its different wavelengths.
    In another exemplary embodiment, the spectral separation system 8 can also include one or more bandpass or interference filters and / or an acousto-optical adjustable filter (or AOTF for "AcoustoOptic Tunable Filters" according to English terminology) and / or an interferometer generally limited in the spectral range. In the case of an interferometer, the different wavelengths of the scattered light beam are separated by interferometry.
    The Raman spectrometry apparatus 1 also comprises a detection filter 9, arranged between the sample and the spectral separation system 8 on the path of the first, respectively, second scattered light beam. The filter 9 is generally placed after the collection optical system 7. This filter 9 cuts the first excitation wavelength  e% Ci and the second excitation wavelength X exC2 , thus eliminating the Rayleigh scattering of said scattered light beams. This filter 9 lets through all the wavelengths of the spectral observation interval. The use of filter 9 differs from the known devices of the prior art in which a rejection filter (or “notch filter” according to the English terminology used) is preferably used, a narrow band filter (of the order of a few nanometers) centered on a determined excitation wavelength in order to eliminate it from the collected signal.
    In an exemplary embodiment, the filter 9 can be a high-pass filter for observing the Raman Stokes scattering. In this case, the filter has a cut-off wavelength situated strictly between the highest excitation wavelength, for example  exC1 , and the lowest observation wavelength A obSi . In another exemplary embodiment, the filter 9 can be a low-pass filter for observing the anti-Stokes Raman scattering. In yet another example, the filter 9 can be a bandpass filter for the simultaneous observation of Raman Stokes and anti-Stokes diffusions. In the case of simultaneous observation of Raman Stokes and anti-Stokes diffusions, an additional filter, of the rejector type centered on the excitation wavelength, is used in order to filter the excitation wavelength in question . Such a rejector filter only makes it possible to block the excitation wavelength in the spectral observation interval. For excitation wavelengths outside the spectral observation interval, it is sufficient to cut all the wavelengths outside the spectral observation interval. A rejection filter can also be used only to limit the brightness in the detection system.
    The first, respectively second, spectrally separated light beam is directed towards the detection system 10. Preferably, the spectral observation interval of the detection system 10 is fixed. This spectral observation interval extends between a first observation wavelength A obSi and a second observation wavelength o oZ , S2 . For example, the spectral observation interval can extend between A obSi = 790 nm and ^ obs 2 = 920 nm. Known prior art Raman spectrometry devices using a fixed spectral separation system are generally configured to acquire measurements over a spectrum as wide as possible in wavelength. According to the configuration of the invention, the width of the spectral observation interval is relatively narrow, for example here of 130 nm.
    In an exemplary embodiment with a diffraction grating-based spectrometer, the detection system 10 comprises a one-dimensional linear detector or a two-dimensional matrix detector, for example a CCD or CMOS type camera for detection in the visible and near-infrared or even InGaAs or MCT for detection in the infrared.
    In yet another exemplary embodiment, the spectral separation system 8 comprises an interference filter, possibly combined with a bandpass filter. In this case, the detection system 10 then includes a detector allowing temporal monitoring of the interference signal on this detector. By temporal signal tracking, we mean an interference system in which we move a mirror as a function of time to observe the interference fringes. The Raman spectrum in relative wave number is reconstructed by Fourier transform from the interferogram.
    The detection system 10 generally comprises a detector which makes it possible to convert the photons it receives from the scattered beam into electrons and to accumulate these electrons. The detection system 10 usually comprises an analog-digital converter suitable for counting the accumulated electrons and converting these measurements into digital values. The detection system 10 thus records in the form of digital values a first, respectively second, signal diffused in Raman, hereinafter called Raman signal, associated with the first, respectively second, light beam diffused and spectrally separated by the spectral separation system 8 in the chosen spectral observation interval.
    A computer 12 is adapted to receive the first, respectively second, Raman signal recorded in the form of digital values. In general, the computer 12 is adapted to generate a first, respectively second, spectrum of the Raman signal, also called Raman spectrum in the following, as a function of the excitation wavelength, in the spectral observation interval chosen in wavelength [Â of , S1 , Â of , S2 ].
    The computer 12 is adapted to calculate a first, respectively a second, part of the Raman scattering spectrum as a function of the relative wave number calculated with respect to the first excitation wave number v exCi , respectively to the second wave number excitation v exC2 , associated with the incident excitation light beam. This first, respectively second, part of the Raman spectrum is calculated in a first, respectively second, Raman spectral domain, expressed in relative wave number as a function of the excitation wave number and of the spectral observation interval, expressed in wave number [v oZ , S2 , -i / oZ , Si ]. For the first excitation wavelength  exC1 , the first Raman spectral range extends between a first relative wave number Δτ ^ corresponding to the difference between the first excitation wave number v exCi and the number maximum observation wave v obSi and a second relative wave number Δν 2 corresponding to the difference between the first excitation wave number v exCi and the minimum observation wave number v obS2 . For the second excitation wavelength X exC2 , the second Raman spectral domain extends between a third relative wave number Δν 3 corresponding to the difference between the second excitation wave number v exC2 and the number maximum observation wave v obS1 and a fourth relative wave number Δν 4 corresponding to the difference between the second excitation wave number v exC2 and the minimum observation wave number v obS2 . In other words, the computer converts the first, respectively second, Raman signal expressed in wavelength into a first, respectively second, part of the Raman spectrum expressed in relative wave number.
    Known prior art Raman spectrometry devices generally use a single excitation wavelength and adapt the spectral separation system and / or the detection system to make it possible to obtain a Raman spectrum expressed as a function of the number of the largest possible relative wave. On the contrary, in the configuration of the invention, different excitation wavelengths are used in combination preferably with a single detection filter or possibly in some cases with several detection filters. The detection filter (s) can remain fixed despite the change in excitation wavelength. A relatively narrow spectral observation interval then makes it possible to obtain as many different parts of the Raman spectrum over different spectral domains in relative wavelength as of excitation wavelengths, then allowing the reconstruction of an extended Raman spectrum. and / or possibly with a high spectral resolution by adapting the spectral separation system 8. The device according to the invention also makes it possible to obtain a few parts of specific Raman spectra with a high spectral resolution and distant from each other in number of relative wave.
    The Raman 1 spectrometry apparatus described above makes it possible to implement the following method for characterizing a sample by Raman spectrometry.
    According to the method of the invention, the source system 2 generates a first incident excitation light beam at a first excitation wavelength  e% Ci which corresponds to a first excitation wave number v exC1 . For example, it is possible to choose as the first excitation wavelength % e% Ci = 785 nm, as the first example represented in FIG. 2 (above).
    The first incident excitation light beam is directed towards the optical system 3 for guidance and / or collimation and / or focusing and / or shaping before being scattered by the sample 6 to be characterized. A first scattered light beam, formed by scattering the first incident excitation light beam on the sample 6, propagates after the sample 6 towards the detection filter 9. Advantageously, this filter 9 blocks the first length of excitation wave A exC1 , thus suppressing Rayleigh scattering.
    The first scattered light beam is then directed to the spectral separation system 8 which generates a first spectrally separated scattered light beam.
    The first spectrally separated scattered light beam is analyzed by the detection system 10. The detection system 10 records a first Raman signal associated with the first scattered light beam. This first Raman signal is detected in a spectral wavelength observation interval.
    This spectral observation interval extends between a first observation wavelength A obSi and a second observation wavelength A obS2 . Equivalently, the spectral observation interval can be expressed in number of waves, with v obSi the first number of observation waves and v obS2 the second number of observation waves. The filter 9 lets through all the wavelengths contained in this spectral observation interval and blocks the excitation wavelengths. According to a variant, an additional filter is used in order to further filter each excitation wavelength and to avoid possible spurious signals at the level of the detection system 10. For example, in FIGS. 2 and 3, the spectral observation interval defined by the spectral separation system 8 extends between 790 nm and 920 nm. In FIG. 2, the detection filter 9 is materialized by a dotted line.
    In general, the computer 12 determines a first Raman spectrum in wavelength from the first Raman signal in the spectral observation interval, in the examples of FIGS. 2 and 3, between 790 nm and 920 nm.
    The computer 12 generates a first part of the Raman spectrum expressed as a function of the relative wave number Av Raman , itself a function of the first excitation wave number v exCi and of the spectral observation interval (in the examples Figures 2 and 3, between 790 nm and 920 nm). In other words, the computer converts the first Raman signal expressed in wavelength into a first part of the Raman spectrum expressed in relative wave number. The first part of the Raman spectrum extends between a first relative wave number At / i = v exCi - v obSi and a second relative wave number Δν 2 = v exCi - v obS2 . For example, in FIGS. 2 and 3, for a first excitation wavelength  e% Ci of 785 nm, for a spectral observation interval of between 790 nm and 920 nm, the first Raman spectral domain s' extends from At / i = 81 cm -1 to Δν 2 = 1869 cm -1 .
    The source system 2 is adapted to generate a second incident excitation light beam at a second excitation wavelength A exCz corresponding to a second excitation wave number v exC2 . Said second excitation wavelength is different from the first excitation wavelength A exCz Φ Â exC1 . For example, one can choose as the second excitation wavelength X exc , 2 = 690 nm, as the second example shown in Figures 2 and 3 (second line from the top in Figures 2 and 3). Advantageously, the difference between the first excitation wavelength and the second excitation wavelength is between a few nm and a few hundred nm.
    As for the first incident excitation light beam, the second incident excitation light beam is directed towards the optical system 3 for guidance and / or collimation and / or focusing and shaping then towards the sample 6 to be characterized. A second scattered light beam is formed by scattering, by the sample 6, of the second excitation incident light beam.
    As for the first scattered light beam, the second scattered light beam is then filtered by the detection filter 9 then separated by the spectral separation system 8, and finally directed towards the detection system 10. This detection system 10 measures and records a second Raman signal associated with the second scattered and spectrally separated light beam. This second Raman signal is detected in the same spectral wavelength observation interval, which extends for the examples of FIGS. 2 and 3 between 790 nm and 920 nm. The detection system 10 then converts the Raman signals into digital values.
    The computer 12 then calculates a second part of the Raman spectrum associated with the second signal broadcast in a second Raman spectral domain, expressed in relative wave number kv Raman as a function of the second excitation wave number vexCz and the spectral interval. wave number observation. The spectral domain of this second part of the Raman spectrum extends between a third relative wave number Δν3 = vexCz - vobSi and a fourth relative wave number Δν4 = vexCz -vobS2. For example, in FIGS. 2 and 3, for a second excitation wavelength 2exCz of 690 nm, in the spectral observation range between 790 nm and 920 nm, the second spectral Raman range extends from Δν3 = 1835 cm -1 to Δν4 = 3623 cm -1 . In other words, the computer converts the second Raman signal expressed in wavelength into a second part of the Raman spectrum expressed in relative wave number.
    Known Raman spectrometry devices generally use a single source, with a single fixed excitation wavelength. A Raman spectrum as wide as possible in relative wave number is then obtained in one go [Av min , Av max ], The other known configuration uses a mobile spectral separation system, for example based on a diffraction grating mobile, and makes it possible to obtain in several times a better resolved and more extended Raman spectrum. Thus, for observation towards high wave numbers, it is in certain cases, in particular for the Raman Optical Activity (ROA, presented later in this description), necessary to move or modify the spectral separation system but also to adopt all the optical adjustments and to adapt the polarization analyzer for the observation of high wave numbers. The method of the invention makes it possible to obtain a Raman spectrum extended towards high wave numbers by only modifying the excitation wavelength of the incident light beam: each excitation wavelength generates a portion of Raman spectrum in a different spectral domain in relative wave number. A chosen set of these different parts of the Raman spectrum makes it possible to reconstruct the extended Raman spectral domain. Particularly advantageously, the detection filter 9 and the spectral separation system 8 can remain fixed. This same extended range of reconstituted Raman spectrum can be obtained with greater spectral resolution in relative wave number, by increasing the resolution of the original spectral separation system.
    The source system 2 can be adapted to generate more than two incident excitation light beams. In the examples of FIGS. 2 and 3, five incident excitation light beams at five excitation wavelengths, respectively 785 nm, 690 nm, 633 nm, 532 nm and 488 nm, are generated either sequentially or simultaneously but spatially offset on a two-dimensional detection system. The method applied to each of the different excitation wavelengths makes it possible to generate five parts of the Raman spectrum as a function of the relative wave number (or Raman displacement Av Raman ) of the spectral interval of observation at each incident light beam d 'excitation (v exc ). FIG. 2 shows that, according to the invention, the detection filter 9 remains unchanged when the excitation wavelengths are modified. As shown in FIG. 2, these are the specificities of the instrumental configuration combining different excitation wavelengths, a detection filter 9 unchanged whatever the excitation wavelength and a spectral observation interval of fixed preference, which make it possible to observe a wide Raman spectral domain, broken down into parts, or according to another choice, to quickly observe Raman spectral domains distant from each other with high spectral resolution.
    The Raman spectral domains associated with these parts of the spectrum extend respectively for the five excitation wavelengths of the above example: between 81 cm ' 1 and 1869 cm' 1 , between 1835 cm ' 1 and 3623 cm ' 1 , between 3140 cm' 1 and 4929 cm ' 1 , between 6138 cm' 1 and 7928 cm ' 1 and between 7833 cm' 1 and 9623 cm ' 1 . The use of a plurality of incident excitation wavelengths makes it possible to reconstruct a spectral range extended towards high wave numbers. FIG. 3 shows the different parts of spectra which make it possible to reconstruct a Raman spectral domain in relative wave number between 80 cm ' 1 and 9623 cm' 1 .
    The measurements made towards the high wave numbers allow in particular the observation of the modes of combinations, of the modes of CH, NH and OH elongation, but also of harmonic modes (or "overtones" according to the Anglo-Saxon terminology sometimes used ) in these high frequencies, and this with an increased efficiency, because the Raman intensity increases to the power of 4 of the inverse of the wavelength, that is to say that it corresponds to a shift towards the blue. This is also the case for higher order harmonic modes in very high frequencies.
    Another example of a reconstructed Raman spectral domain is proposed in Table I below. In this example, the spectral observation range is between 535 nm and 615 nm. The width of the 80 nm spectral observation interval is here less than 100 nm. The source system 2 is adapted to sequentially generate five excitation wavelengths, respectively 633 nm, 561 nm, 532 nm, 488 nm and 473 nm. The lower and upper bounds of each Raman spectral domain in relative wave number are calculated from the formula (1) mentioned above. The following Tables I and II summarize the Raman spectral domains in relative wave number obtained for two spectral observation intervals, between 535 nm and 615 nm for Table I and between 790 nm and 920 nm for Table II:
    2-exc(Nm) àv min (cm ' 1 ) for À obsl = 535 nm AVmax (cm)for^ Obs2 = 615 nm applications 633 -2894 -462 Spectral footprint in anti-Stokes scattering, coherent anti-Stokes Raman scattering, with low-pass filter 561 -866 1565 Low frequency Stokes and anti-Stokes scattering, with band filter 532 105 2537 Spectral footprint area 488 1800 4232 Extension for v 0H , v NH andv CH with overlap area 473 2450 4881 Extension for v 0H , v NH and v CH , combination modes and harmonic modes
    Table I
    2-exc(Nm) Av min (cm ' 1 ) for T oZ , sl = 790 nm AV-max ( cm ) for ^ Obs2 = 920 nm applications 1064 -3260 -1471 Anti-Stokes scattering Coherent anti-Stokes Raman scattering, combination modes and v CH 914 -1717 71 Anti-Stokes scattering coherent anti-Stokes Raman scattering 785 81 1869 Spectral footprint area 690 1835 3623 Overlay area, combination modes, v NH andv CH 633 3140 4929 Extension for v 0H , v NH and v CH , combination modes and harmonic modes
    Table II
    Figure 4 shows an example of parts of scattering spectra
    Raman for the Stokes configuration obtained using the Raman spectrometry method described above. The ordinate axis corresponds to the intensity of the electronic signal recorded by the detection system in arbitrary units (u. A.). The abscissa axis corresponds to the observation wavelength 10 (in nm). The different curves are associated with different excitation wavelengths, of 700 nm, 710 nm, 720 nm, 730 nm, 740 nm and 750 nm, respectively. The spectral observation range here ranges from 760 nm to 880 nm. The width of the spectral observation interval is here also relatively narrow, limited to 120 nm. These different parts of Raman spectra of acetonitrile were obtained with a spectral separation system by diffraction grating, for example of 830 lines / mm and a detection system comprising a CCD camera, for example of 2048 pixels.
    FIG. 5 represents an example of parts of the Raman scattering spectrum, for the Stokes configuration, in relative wave number corresponding to the wavelength spectra of FIG. 4. The ordinate axis corresponds to the signal intensity electronics recorded by the detection system in arbitrary units (au). The abscissa axis corresponds to the Raman displacement in relative wave number (in cm ' 1 ). Each part of the spectrum represented in FIG. 5 corresponds to a spectrum presented in FIG. 4. The parts of spectrum in FIG. 5 are generated by the Raman displacement computer in relative wave number for the same spectral observation interval as that of FIG. 4 with respect to the different excitation wavelengths. The configuration of the spectral separation system and of the detection system remains identical for all the excitation wavelengths. The spectral range of all the parts of the Raman spectrum here ranges from about 0 cm -1 to 2800 cm -1 .
    FIGS. 6 and 7 show examples of the Raman spectrum for the anti-Stokes configuration, as a function of the observation wavelength for FIG. 6 and as a function of the relative wave number for FIG. 7.
    In Figures 6 and 7, the ordinate axis corresponds to the strength of the Raman signal recorded by the detection system in arbitrary units (u. A.). These spectra were obtained for a spectral observation interval extending between 660 nm and 780 nm, with a spectral separation system by diffraction grating, for example of 830 lines / mm, and a detection system comprising a CCD camera. for example 2048 pixels. The width of the spectral observation interval is here also relatively narrow, limited to 120 nm. The different curves are associated with different excitation wavelengths of 788 nm, 800 nm, 820 nm and 850 nm respectively.
    Alternatively, the Raman 1 spectrometry apparatus can be used to measure non-linear Raman effects such as Hyper Raman, Stimulated Raman, and coherent Raman anti-Stokes scattering (CARS). For example, the Raman spectrometry device 1 makes it possible to measure the Hyper Raman effect with 2 photons or more generally with n photons, where n is a natural integer greater than or equal to 2. In this configuration, the source system 2 generates an incident excitation light beam at an excitation wavelength denoted X exc . The computer 12 is adapted to generate a portion of the Raman spectrum in a spectral observation interval, said spectral observation interval extending next to a wavelength corresponding to a fraction 1 / n of the length of excitation wave X exc , for example at half the excitation wavelength in the case where n = 2. Optionally, an additional filter is placed in the apparatus between the sample 6 and the detection system 10, to cut the wavelength corresponding to this fraction 1 / n of the excitation wavelength. The computer 12 is adapted to generate part of the 2-photon Hyper Raman spectrum in a spectral domain in relative wave number:
    Raman - 2 * V exc Vobs (4)
    The relative wave number for the 2-photon hyper Raman signal is here equal to the difference between twice the number of excitation waves and the number of observation waves. Here too, the relative wave number is therefore formed of a linear combination of the excitation wave number and the observation wave number.
    FIG. 8 represents an example of Hyper Raman scattering spectra obtained using the variant of the Raman spectrometry method described in the previous paragraph. The ordinate axis corresponds to the strength of the Raman signal recorded by the detection system in arbitrary units (u. A.). The abscissa axis corresponds to the observation wavelength (in nm). The different curves are associated with different excitation wavelengths of 1160 nm, 1180 nm, 1210 nm, 1240 nm, 1270 nm and 1300 nm, respectively. The spectral observation range here ranges from 635 nm to 705 nm. The width of the spectral observation interval is here limited to around 70 nm for most spectra. In addition, a Raman spectrum of around 200 nm is shown for a spectrum at the excitation wavelength of 1300 nm, by rotating the diffraction grating. These different spectra were obtained with a spectral separation system by diffraction grating, for example of 1800 lines / mm and a detection system comprising a CCD camera, for example of 2048 pixels.
    FIG. 9 represents an example of parts of the Hyper Raman scattering spectrum in relative wave number. The ordinate axis corresponds to the intensity of the electronic signal recorded by the detection system in arbitrary units (au). The abscissa axis corresponds to the Raman displacement in relative wave number (in cm ' 1 ) in the hyper Raman configuration with two photons (deduced from formula (3)). The parts of the spectrum represented in FIG. 9 correspond to the spectra presented in FIG. 8 with a modification of the abscissa axis by conversion of the wavelengths into relative wave numbers, the relative wave numbers being calculated for each part of the Raman spectrum as a function of the excitation wavelength proper to each excitation light beam and of the observation wavelength in the spectral observation interval which remains fixed for all the lengths of excitation wave. The computer 12 generates the parts of the spectrum of FIG. 9 as a relative wave number of the spectral observation interval of FIG. 8 with respect to each excitation wavelength, the configurations of the spectral separation systems and of detection being identical. The Raman spectral domain (deduced from formula (3)) here extends in relative wave number from - 200 cm ' 1 to 3300 cm' 1 .
    In another variant, the Raman 1 spectrometry apparatus can be used to carry out Raman Optical Activity (or ROA) measurements. There are three basic types of mounting: ICP (Incident circular polarization) mounting, SCP (Scattered Circular Polarization) mounting and DCP (Dual Circular Polarization) mounting. Sample 6 to be analyzed is then either chiral, or of primary or secondary chiral structure. The measurement of the ROA spectrum is based on a difference in Raman signals resulting from a polarization modulation of the excitation incident light beam and / or of the scattered light beam. FIG. 10 provides a schematic representation of the various elements of a Raman 100 spectrometry apparatus within the framework of Raman Optical Activity measurements. The elements common to Figures 1 and 10 bear the same references and will not be described again hereinafter.
    The source system 2 generates a first incident excitation light beam at a first excitation wavelength. The incident excitation light beam is directed towards a polarization device 4. Said polarization device 4 comprises for example a polarizer and / or a prism or a half-wave plate or a quarter-wave plate adapted to polarize the beam luminous incident of excitation either according to at least two polarization states orthogonal to each other such as for example two circular or elliptical polarization states, or according to a linear polarization of random direction perpendicular to the axis of propagation simulating a non-polarized beam. The incident excitation light beam thus polarized by the polarization device 4 is then directed towards the sample 6 to be characterized.
    After the sample, the light beam is filtered by the detection filter 9. The Raman spectrometry apparatus 100 further comprises a polarization analyzer 7 suitable for analyzing the filtered light beam. The polarization analyzer 7 comprises a diffuser and a right and / or left circular polarization selector or a right and / or left elliptical polarization selector or a linear polarization splitter located after a circular polarization to linear polarization converter, for example a quarter wave blade. After the polarization analyzer 7, the light beam scattered and analyzed in polarization is spectrally separated by the spectral separation system 8, then directed towards the detection system 10. As a variant, the polarization analyzer 7 can be positioned before the filter in detection 9.
    Analogously to the Raman spectrometry method described above, the first excitation light beam at a first excitation wavelength polarized according to a first polarization leads to the recording of a first Raman signal.
    The polarization device 4 is configured to modify the polarization state of the excitation and / or scattered incident light beam, for example in the first place according to a left circular polarization. According to the Raman spectrometry method described above, a second excitation light beam at this first excitation wavelength and polarized according to a second polarization leads to the recording by the detection system 10 of a second Raman signal.
    The computer 12 is adapted to generate a third Raman signal, called the Raman Optical Activity spectrum, this third signal corresponding to the difference of the first Raman signal and the second Raman signal or, according to another configuration, to a linear combination of a set of Raman spectra of different polarizations, expressed as a relative wave number of the excitation wave number v exCi with respect to the spectral range of observation [v of) S2 , v oZ , S1 ].
    The source system 2 is adapted to generate at least two different excitation wavelengths. The method applied for each of the different excitation wavelengths makes it possible to generate at least two parts of the Raman optical activity spectrum as a function of the relative wave number of the spectral interval of observation with respect to the number of wave corresponding to the incident excitation light beam. The use of multiple excitation incident wavelengths makes it possible either to reconstruct a wide spectral domain towards high wave numbers, or to quickly observe well resolved Raman spectral domains distant from each other. The two solutions make it possible to complete and refine the spectral characterization of the sample 6 studied, for example the chirality in the case of the Raman Optical Activity.
    In another variant, the Raman 1 spectrometry device can be used to carry out Hyper Raman Optical Activity (or HROA) measurements. In this case, the spectrometry device is declined as the variant of Raman Optical Activity, with a two-photon excitation instead of one or n photons if we observe the higher order nonlinear HROA effect. In the Hyper Raman (or HROA) configuration, only the excitation and the optical system 3 for guidance and / or collimation and / or focusing and / or beam shaping must be adapted for a wavelength of double excitation than that used in the Raman configuration (or ROA). Optionally, a suitable additional filter can be added to cut off the excitation wavelength which can cause noise to the Raman system, even at a wavelength much greater than the range of observation.
    In another variant, the spectral separation system 8 and / or the detection filter 9 and / or the interference system and / or the detection system 10 is suitable for recording a Raman spectrum, respectively ROA spectrum, associated with said first light beam. scattered and detected in another spectral interval of observation in reduced wavelength [â oZ , S3 , â oZ , S4 ]. By keeping the same number of detection elements, another broadcast signal is then detected and thus has a higher spectral resolution than the first Raman signal. The computer 12 receives the other signal from the detection system 10 and generates another spectrum of said other broadcast signal as a function of the wavelength of said other spectral observation interval [â oZ , S3 , â oZ , S4 ]. The computer 12 is also adapted to generate another part of the Raman spectrum in relative wave number as a function of the difference between the first wave number associated with the first excitation light beam and the wave numbers of said spectral range of reduced observation [v of) S: i , v 0f) S4 ], said other spectral range extending between a fifth relative wave number Δν 5 = v exCi - v obS3 and a sixth relative wave number Δν 6 = v exCi ~ v 0 bs 4 · In this way, as the number of detection elements is kept in the reduced spectral range, the spectral resolution of the Raman scattering spectrum obtained increases. In practice, it increases inversely to the reduction ratio of the spectral interval of observation in wavelength.
    In another variant, a second spectral separation system (not shown) can be added on the path of the light beam after the first spectral separation system 8 which makes it possible to reduce the spectral interval of observation and thus to obtain domains Raman spectral spectra in very resolved relative waves, typically of the order of a few tens of cm ' 1 .
    In another variant, the Raman 1 spectrometry apparatus allows a spectral separation system to be calibrated precisely and quickly in wavelength. For this, the source system 2 comprises a laser source tunable in wavelength, or of different discrete wavelengths selected. The source system is originally calibrated or measured in wavelength with a lambdam meter for example. These excitation light beams, the wavelength of which is determined, are scattered by a reference sample having one or more fine and well-known spectral bands. The change in excitation wavelength allows the spectral range of the spectral separation system to be scanned and calibrated. The use of the Raman 1 spectrometry apparatus according to the invention then makes it possible to dispense with spectral calibration lamps.
    The Raman spectrometry device according to the invention can relate to all Raman spectrometers, including portable and on-board devices, which work with a fixed spectral observation interval, suitable for measurements on site, from satellites, from extraterrestrial probes or in the depths of the oceans. For these different applications, spectral reproducibility and the absence of moving parts is crucial for the durability of instruments and measurements.
    The Raman spectrometry device according to the invention can also relate to Raman spectrometers for which measurements with a large dynamic range and a high signal-to-noise ratio at high wave numbers are desired: the spectral range of observation in length d wave for which the spectral separation and detection system is optimized, regardless of the Raman domains probed. In particular, it makes it possible to probe harmonics of orders higher than very high wave numbers, in particular greater than 5000 cm -1 . In the same way, the invention also makes it possible to quickly probe with a high resolution several narrow and very distant Raman spectral domains in relative wave number with these same efficiency advantages.
    The present invention makes it possible to probe Raman Stokes spectral domains with a relative wave number much greater than the initial observation wave number: for example, if the observation is around 10,000 nm (1000 cm -1 ) , by exciting at 1000 nm (10000 cm ' 1 ), the invention makes it possible to easily measure a spectrum of very high wave numbers around 9000 cm' 1 , where the third harmonics of the CH elongation modes are located.
    In addition, when the fluorescence parasites the Raman spectra, the use is to favor a laser excitation in the near infrared at 785 nm and 1064 nm. Unfortunately, at these exciting wavelengths, the detection of high wavenumbers, such as stretching CH (stretching 3000 cm ' 1 ) and beyond, drops drastically, due to the low efficiency of detection systems: this comes back to observe the infrared domains (1030 nm and 1563 nm respectively). The present invention, while retaining the same observation range in nm and the optimized efficiency of the spectral separation system and of the detection system, makes it possible to easily measure these high relative wave numbers while increasing the Raman effect (proportional to 1 / Â ^ XC ) and always avoiding the fluorescence which remains confined in the same spectral range of emission in nm whatever the excitation wavelength.
    权利要求:
    Claims (14)
    [1" id="c-fr-0001]
    1. Raman spectrometry apparatus (1; 100) for characterizing a sample (6), the apparatus (1; 100) comprising a source system (2) generating a first incident incident excitation light beam at a first length of excitation wave, a spectral separation system (8) receiving a first scattered light beam formed by scattering of said first incident excitation light beam on the sample (6) and spectrally separating said first scattered light beam, a detection system (10) making it possible to record a first Raman signal associated with said first scattered light beam and detected in a spectral wavelength observation interval extending between a first observation wavelength (Â of , S1 ) and a second observation wavelength (Â of , S2 ), a computer (12) receiving the first Raman signal from said detection system (10) and generating a first part of the Raman spectrum as a function of the Raman displacement in a first Raman spectral domain in relative wave number, said first Raman spectral domain extending between a first relative wave number which is a function of the first excitation wavelength and of the first wavelength observation wave and a second relative wave number depending on the first excitation wavelength and the second observation wavelength;
    characterized in that:
    said source system (2) is adapted to generate at least a second incident excitation light beam at a second excitation wavelength, said second excitation wavelength being different from the first wavelength of excitation, said spectral separation system (8) being adapted to receive a second scattered light beam formed by scattering of said second incident excitation light beam on the sample (6) and to spectrally separate said second scattered light beam, said detection system (10) being adapted to detect and record a second Raman signal associated with said second light beam scattered in the same spectral wavelength observation interval, said computer (12) being adapted to measure the second Raman signal and to generate a second part of the Raman spectrum as a function of the Raman displacement in a second dom Raman spectral range in relative wave number, said second Raman spectral domain extending between a third relative wave number which is a function of the second excitation wavelength and of the first observation wavelength and a fourth relative wavenumber as a function of the second excitation wavelength and the second observation wavelength.
    [2" id="c-fr-0002]
    2. Raman spectrometry apparatus (1; 100) according to claim 1, wherein the source system (2) is adapted to generate a plurality of excitation light beams at a plurality of excitation wavelengths.
    [3" id="c-fr-0003]
    3. Raman spectrometry apparatus (1; 100) according to claim 1 or 2, wherein the source system (2) comprises a plurality of monochromatic laser sources, a laser source tunable in optical frequency and / or a source in a plurality selectable or spatially separable monochromatic excitation wavelengths.
    [4" id="c-fr-0004]
    4. Raman spectrometry apparatus (1; 100) according to one of claims 1 to 3, wherein the source system (2) comprises a continuous or pulse laser source.
    [5" id="c-fr-0005]
    5. Raman spectrometry apparatus (1; 100) according to any one of claims 1 to 4, further comprising at least one device for polarizing (4) the excitation light beam between the source system (2) and l sample (6), said polarization device (4) being adapted to polarize the first incident excitation light beam and, respectively, the second incident excitation light beam according to at least two polarization states orthogonal to each other.
    [6" id="c-fr-0006]
    6. Raman spectrometry apparatus (100) according to one of claims 1 to 5, further comprising a polarization analyzer (7) disposed between the sample (6) and the detection system (10), the analyzer of polarization (7) being adapted to analyze and / or separate in polarization the first scattered light beam and, respectively, the second scattered light beam.
    [7" id="c-fr-0007]
    7. Raman spectrometry apparatus (1; 100) according to any one of claims 1 to 6, in which the computer (12) is adapted to generate a first, respectively second, part of the hyper Raman scattering spectrum in a first, respectively second, hyper Raman displacement spectral domain in relative wave number, in which the first relative wave number is equal to the difference between an integer multiple n of the first excitation wave number and the first number of observation wave, the second relative wave number is equal to the difference between an integer multiple n of the first excitation wave number and the second observation wave number, the third relative wave number is equal to the difference between an integer multiple n of the second excitation wave number and the first observation wave number, the fourth relative wave number is equal to the difference between a multiple integer n of the second excitation wave number and the second observation wave number, the integer multiple n being greater than or equal to two.
    [8" id="c-fr-0008]
    8. Raman spectrometry apparatus (1; 100) according to one of claims 1 to 7, comprising a detection filter (9) configured to cut the first excitation wavelength and / or the second wavelength excitation.
    [9" id="c-fr-0009]
    9. Raman spectrometry apparatus (1; 100) according to one of claims 1 to 8, in which the detection filter (9) comprises at least a high-pass filter, a low-pass filter or a band-pass filter or a combination of said filters.
    [10" id="c-fr-0010]
    10. Raman spectrometry apparatus (1; 100) according to one of claims 1 to 9, in which the spectral separation system (8) comprises a spectrometer based on a diffraction grating (s), prism (s) and / or grism (s) or a spectrometer comprising a combination of diffraction grating (s) and / or prism (s) and / or grism (s).
    [11" id="c-fr-0011]
    11. Raman spectrometry apparatus (1; 100) according to one of claims 1 to 10, wherein the spectral separation system (8) comprises an interference filter and / or an interferometer.
    [12" id="c-fr-0012]
    12. Raman spectrometry apparatus (1; 100) according to one of claims 1 to 11, wherein the detection filter (9) is fixed.
    [13" id="c-fr-0013]
    13. Raman spectrometry apparatus (1; 100) according to one of claims 1 to 12, wherein the detection system (10) comprises a single-channel detector or a one-dimensional linear detector or a two-dimensional matrix detector.
    [14" id="c-fr-0014]
    14. Raman spectrometry method comprising the following steps:
    - generation of a first incident excitation light beam at a first excitation wavelength by a source system (2);
    - spectral separation of a first scattered light beam formed by scattering the first incident excitation light beam on a sample (6);
    recording of a first Raman signal associated with the first scattered light beam, detected in a spectral interval of observation in wavelength extending between a first observation wavelength and a second wavelength of observation;
    - calculation of a first part of the Raman spectrum as a function of the Raman displacement in a first Raman spectral domain in terms of relative wave number, said first Raman spectral domain extending between a first relative wave number as a function of the first length d excitation wave and the first observation wavelength and a second relative wave number function of the first excitation wavelength and the second observation wavelength;
    - Generation of at least a second incident excitation light beam at a second excitation wavelength by the source system (2), said second excitation wavelength being different from the first length of excitation wave;
    - spectral separation of a second scattered light beam formed by scattering the second incident excitation light beam on the sample (6);
    - recording of a second Raman signal associated with the second scattered light beam, detected in the same spectral wavelength observation interval;
    - calculation of a second part of the Raman spectrum as a function of the Raman displacement in a second Raman spectral domain in relative wave number, said second Raman spectral domain extending between a third relative wave number depending on the second length d excitation wave and the first observation wavelength and a fourth relative wave number function of the second excitation wavelength and the second observation wavelength;
    - Combination of said first part of the Raman scattering spectrum and of said second part of the Raman scattering spectrum to reconstruct a Raman scattering spectrum over a wide spectral domain in relative wave number and / or having an increased spectral resolution in the first and / or second Raman spectral domain.
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    同族专利:
    公开号 | 公开日
    FR3081221B1|2021-07-30|
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    JP2021526632A|2021-10-07|
    US20210215537A1|2021-07-15|
    WO2019220047A1|2019-11-21|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US20040127778A1|2001-01-09|2004-07-01|Lambert James L.|Identifying or measuring selected substances or toxins in a subject using resonant raman signals|
    WO2021195471A1|2020-03-26|2021-09-30|Innovative Photonic Solutions, Inc.|Method for selection of raman excitation wavelengths in multi-source raman probe|
    EP3907498A4|2020-05-06|2021-11-10|Innovative Photonic Solutions Inc|Method for selection of raman excitation wavlengths in multi-source raman probe|
    法律状态:
    2019-04-23| PLFP| Fee payment|Year of fee payment: 2 |
    2019-11-22| PLSC| Publication of the preliminary search report|Effective date: 20191122 |
    2020-03-11| PLFP| Fee payment|Year of fee payment: 3 |
    2021-05-28| PLFP| Fee payment|Year of fee payment: 4 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1854096|2018-05-16|
    FR1854096A|FR3081221B1|2018-05-16|2018-05-16|RAMAN SPECTROMETRY APPARATUS AND METHOD|FR1854096A| FR3081221B1|2018-05-16|2018-05-16|RAMAN SPECTROMETRY APPARATUS AND METHOD|
    EP19742428.6A| EP3794325A1|2018-05-16|2019-05-13|Composite multispectral raman spectroscopy method and device|
    PCT/FR2019/051076| WO2019220047A1|2018-05-16|2019-05-13|Composite multispectral raman spectroscopy method and device|
    JP2020564666A| JP2021526632A|2018-05-16|2019-05-13|Composite multispectral Raman spectroscopy measurement method and equipment|
    US17/055,295| US20210215537A1|2018-05-16|2019-05-13|Composite multispectral raman spectroscopy method and device|
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