• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention describes a device for measuring the polarization state of a beam comprising two waveguides perpendicular to each other and to the direction of beam propagation, intersecting in an intersection zone whose center represents a coordinate origin on which the beam impinges ; two means that cover above and below said guides being their refractive indexes at the wavelength of the beam less than that of the guides; a diffuser in the area of intersection of the guides and offset with respect to the origin of coordinates in different magnitudes with respect to each of the longitudinal axes of the guides; and a power sensor in each of the four output ports of the guides. A corresponding method is also described. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2566684A1
    申请号:ES201630162
    申请日:2016-02-11
    公开日:2016-04-14
    发明作者:Alba ESPINOSA SORIA；Amadeu GRIOL BARRES；Alejandro José MARTÍNEZ ABIETAR
    申请人:Universidad Politecnica de Valencia；
    IPC主号:
    专利说明:

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    DEVICE AND METHOD FOR MEASURING THE POLARIZATION STATUS
    OF AN INCIDENT BEAM
    Field of the Invention
    The present invention relates to the field of electromagnetic waves, and more specifically to the measurement of the state of polarization of electromagnetic waves, for example, of a beam of light.
    Background of the invention
    Polarization is a fundamental property of electromagnetic waves, including light. An electromagnetic wave consists of an electric field and another magnetic field perpendicular to each other that oscillate in a plane perpendicular (called the polarization plane) to the direction of propagation of said wave. The polarization of said wave refers to the oscillation of the electric field vector in the plane perpendicular to the direction of propagation. The projection of the real part of the electric field vector on the polarization plane generally describes an ellipse with an associated direction of rotation (which may be left or right) that is called a polarization ellipse. Said ellipse defines the polarization of an electromagnetic wave. If the relationship between the axes of the ellipse is unity, the polarization is circular. If this relationship is infinite, then the polarization is linear. In general, the polarization plane can be considered to be the xy plane while the wave propagates in parallel to the z axis.
    In numerous applications (chemistry, astronomy, optical communications) it is absolutely necessary to know
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    the polarization state (EDP) of an electromagnetic wave. For this, a usual form of parametric representation that does not require any graphic description (as in the case of the ellipse of
    polarization) is the use of the Stokes S vector, composed of four elements, which is obtained from six parameters defined in units of power unit (W / m2) according to equation (1) below:
    image 1
    where IH, IV, I45, I135, IR and IL correspond, respectively, to the power density of the incident electromagnetic wave measured by polarizers ideal for horizontal linear polarization, vertical linear polarization, linear polarization oblique to 45 °, linear polarization oblique to 135 °, right circular polarization and left circular polarization.
    To measure the EDP of a monochromatic electromagnetic wave, a set of Q polarization analyzers whose response is a certain optical power Pq (q = 1, ..., Q), which can be expressed is usually used
    by a vector P. This response can be characterized
    by a four component vector, A = [aqf1, aq, 2,
    aq, 3, aq, 4] defined by the following equations (2) to (5):
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    <7q, l ~ bqjf + bq v (2)
    a <. 2 = bqH-bqV (3)
    ^ q.3 = bq45-bql35 (4) flq.4 bqR-bqL (5)
    where the coefficients bq, i are defined as the quotient between the power measured by the q-th analyzer Pq when it is struck with an ideal polarization i (i can be H, V, 45, 135, R and L, following the nomenclature of the definition of Stokes parameters) and the power density of the incident wave.
    The total response of the analyzer system is the
    polarimetric measurement matrix W, which is a 4xQ matrix
    which contains in its row q-esima the vector A
    corresponding to the response of the q-th analyzer. The
    matrix W is expressed by the following equation (6):
    image2
    Thus the following matrix relation is obtained, defined by equation (7):
    image3
    where S ~ * is the Stokes vector of any input signal. If Q = 4 and the outputs of each analyzer are
    linearly independent, then W is invertible, and the Stokes vector of the incident signal, which provides the complete information about the EDP, is obtained according to the following equation (8):
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    image4
    A device that meets the above requirements and allows to fully determine the four Stokes parameters of an incident wave, and therefore its EDP, is called Stokes pole meter.
    For the specific case of measuring the EDP of light that propagates in free space, a combination of quarter wave plates and linear polarizers is generally used as polarization analyzers, some of which can be rotated mechanically. In addition, they can be arranged in series (each analyzer measures the polarization of the signal at the output of the previous analyzer) or in parallel (a splitter is used to obtain four light beams from the initial light beam and different analyzers are used, linearly independent, for each beam). As an example of this last case, US 3572938 can be mentioned. These components, both quarter wave plates and linear polarizers, are bulky (size of several orders of magnitude greater than the wavelength to be measured) and expensive manufacture. In addition, if the plates have to be rotated mechanically to obtain measurements at different temporal instants (for example, the plate is usually rotated in four different angular positions, then the light passes through a fixed linear polarizer and the output power is measured), It is not possible to measure EDP in real time.
    To measure the EDP of light that propagates in optical fiber, components similar to those mentioned above are used, but integrated in fiber. For example, in US patent 6211957 a fiber meter is described which uses, in addition to a quarter wave plate inscribed in the fiber, a diffraction network to sample the power of
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    The guided light. This type of polarimeter is called online since only one portion of the guided wave is extracted to measure its EDP and the rest continues to travel through the fiber, so it is very useful in optical communications networks. However, also in this case they are components with a size larger than the wavelength, which cannot be integrated or extended to other wavelength ranges. In addition, its cost is very high.
    To achieve the miniaturization of a polarimeter (in principle one could think of reducing its size even below the wavelength of the light from which its EDP is to be measured) and, consequently, a reduction in its cost, recently they have Different research projects have emerged, proposing new approaches based on the optical response of structured metals in the microscale and nanoscale. We can classify these works in polarizers based on plasmonic resonators and polarizers based on meta-surfaces.
    The following works belong to the first class:
    F. Afshinmanesh, J. S. White, W. Cai, M.L. Brongersma ("Measurement of the polarization state of light using an integrated plasmonic polarimeter". Nanophotonics 1, 125-129 (2012)) and Y. B. Xie, Z.-Y. Liu, Q.-J. Wang, Y.-Y. Zhu, X.-J Zhan, X.-J. ("Miniature polarization analyzer based on surface plasmon polaritons". Appl. Phys. Lett. 105, 101017
    (2014)), which demonstrate the complete measurement of EDP using metallic nanostructures that act as linearly independent parallel polarization analyzers. In these articles all Stokes parameters of the incident electromagnetic wave are obtained using a structure
    Measured with a very small size, below 10
    2
    ^ m, but the structures used have many
    drawbacks: to make them you have to drill the metal
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    with nanometric resolution, which does not allow its production at low cost; they produce many losses in the signal they measure, so they cannot be used as poles in the line; they are not broadband, since the response occurs in a small spectral range; The concept is not exportable to other frequency regimes of the electromagnetic signal. The following belong to the second:
    D. Wen et al. ("Metasurface for characterization of the polarization state of light". Opt. Express 23, 1027210281 (2015)) demonstrate the measurement of non-complete EDP using a meta-surface formed by metallic nanostructures. This work is improved in A. Pors et al., ("Plasmonic metagratings for simultaneous determination of Stokes parameters," Optics 2, 716-723 (2015)) where the use of three meta-surfaces placed in proximity s ^ that allow the EDP to be extracted complete from measurements of diffracted beam intensity in directions other than normal (z axis) not contained in the xy polarization plane, and whose direction of propagation varies according to the wavelength. To measure the intensity of these beams
     so  simple is more practical than you do
     spread  on the plane of polarization, where it has
     created the  meta surface, so that a simple
    interconnection to external optical fibers (to measure intensity). This is the novelty introduced in the JP JP Balthasar Mueller, Kristjan Leosson, and Federico Capasso, "Ultracompact metasurface in-line polarimeter," Optics 3, 42-47 (2016) where the meta-surface designed and located in the x-plane allows generate four beams of light propagating in different directions on a dielectric medium located in said plane, being the power of each of these four beams
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    proportional to elliptic polarization states of the incident wave. After that, the power of each beam is extracted using diffraction networks and is measured externally, which allows the EDP to be recomposed. In all polarometers based on meta-surfaces the size of the measurement region (where the light to be measured affects) and which would define the minimum size of the polarimeter in the xy plane is of the order of tens of ^ m. In addition, they all use nanostructured metals, which makes manufacturing difficult (especially on a large scale) and introduces absorption losses that would reduce the performance of the EDP meter.
    Therefore, there is still a need in the art for devices and methods that allow measuring the state of polarization of a beam of electromagnetic radiation that overcomes the disadvantages of the prior art. In particular, it would be desirable to have such a device that reduces production costs, for example, avoiding the inclusion of nanostructured metals. In that sense, it would be very appropriate if the device could be completely manufactured using silicon microelectronic technology, which allows large-scale and low-cost manufacturing (per device). It would also be desirable to have such a device whose size is reduced with respect to those of the prior art, since nanophotonics is allowing devices with sizes to be obtained even below the wavelength of the incident radiation, which would further help to reduce its production costs (possibility of manufacturing more chips in the same wafer). It would also be desirable to have a device that allows measuring the polarization state of an electromagnetic radiation beam in a simple, fast, real-time manner and both of beams that propagate in free space and of beams that are
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    They propagate by fiber.
    Summary of the invention
    In a first aspect the present invention discloses a device for measuring the state of polarization of an incident beam of electromagnetic radiation. The device comprises:
    - two waveguides located on the same plane, perpendicular to each other and perpendicular to the direction of propagation of the incident beam, formed by dielectric or semiconductor materials that intersect in an intersection zone whose center represents an origin of coordinates on which it affects the incident beam;
    - two means, also dielectric or semiconductors, that cover said waveguides above and below such that their indexes of refraction to the wavelength of the incident beam are smaller than the index of refraction of the waveguides;
    - a diffuser of the incident beam, the diffuser being
    located in the intersection zone of the waveguides and offset with respect to the origin of
    coordinates in different magnitudes with respect to
    each of the longitudinal axes of the waveguides; Y
    - a sensor to measure the power of a beam of
    output arranged in each of the four output ports of the waveguides.
    Additionally, according to a preferred embodiment of the present invention, the device further comprises calculation means for determining the polarization state of the
    incident beam by calculating the Stokes vector S from the inverse of the polarimetric measurement matrix
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    W and the power vector P, determined in turn by the sensors, according to the equation:
    image5
    Alternatively, according to another preferred embodiment of the present invention, the device further comprises connection means with an external calculation device (for example, a computer) to send the power values detected by the sensors to said external calculation device, with this Last of calculating the polarization state of the incident beam from the power values sent by the connection means.
    According to a second aspect of the present invention, a method for measuring the polarization state of an incident beam of electromagnetic radiation is disclosed. The method comprises the steps of:
    a) make an electromagnetic radiation beam strike a diffuser;
    b) diffusing the incident beam, by means of said diffuser, along four directions defined by two perpendicular waveguides;
    c) measuring the power of an output beam at each of the four outputs of said two waveguides;
    d) calculate the polarimetric measurement matrix W and the
    power vector P corresponding to the incident beam from the power measured in the
    waveguide output; Y
    e) calculate the Stokes vector S from the
    inverse of the polarimetric measurement matrix W and the power vector P calculated in step d), the Stokes vector S being representative of the
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    polarization state of the incident beam.
    Brief description of the figures
    The present invention will be better understood with
    reference to the following figures illustrating a
    Preferred embodiment of the invention, provided by way of example, and which should not be construed as limiting the invention in any way.
    Figure 1 is a top view of a device according to the preferred embodiment of the present invention.
    Figure 2 is a cross-sectional view of the device shown in Figure 1.
    Detailed description of preferred embodiments
    A detailed description of a preferred embodiment of the present is provided below.
    invention.
    Figures 1 and 2 show a view from above and in cross-section, respectively, of the structure of a device according to the preferred embodiment of the present invention for measuring EDP.
    As can be seen in Figure 1, the device comprises two waveguides (10, 20) located
    on the same plane, perpendicular to each other and perpendicular to the direction of beam propagation
    incident (50) to be measured. The waveguides (10, 20)
    they are formed by dielectric or semiconductor materials, preferably transparent to the wavelength in consideration of the incident beam (50). Preferably the waveguides are of a material selected from the group comprising silicon and silicon nitride. In addition, the waveguides (10, 20) intersect
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    in an intersection zone whose center represents an origin of coordinates on which the incident beam (50) affects. Figure 1 shows the origin of coordinates such as the intersection between the x-axis and the y-axis, each of these axes corresponding to the longitudinal axis of one of the waveguides (10, 20). Figure 2 shows the origin of coordinates as the intersection between the z axis and the x axis, the z axis corresponding to the axis of displacement of the incident beam (50).
    The waveguides (10, 20) represent a first medium (30). In order to be able to confine the electromagnetic radiation of the incident beam (50) in them, they are coated above and below with two means (32, 34) also dielectric or semiconductors such that their indexes of refraction (n2, n3) to the length of Wave of interest are less than the refractive index (n1) of the waveguides (10, 20): n1> n2, n3.
    The waveguides (10, 20) have a rectangular section of width w and height t. If it is not high enough, the dimensions of the waveguides (10, 20) w and t will be smaller than the radiation wavelength that they can confine and guide.
    The device further comprises a diffuser (40) of the incident beam (50) which preferably has revolution symmetry about an axis corresponding to the direction of propagation of the incident beam (50), that is, around the z axis according to the representation in the Figures 1 and 2. The diffuser (40) is of a dielectric, metallic or semiconductor material (not necessarily transparent to the wavelength under consideration). In the embodiment shown in Figures 1 and 2 it is specifically a cylinder of diameter D and height h, both dimensions being smaller than the wavelength of the incident beam (50).
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    The diffuser (40) is located at the level of the intersection zone of the waveguides (10, 20) and offset with respect to the origin of coordinates in different magnitudes with respect to each of the longitudinal axes of the waveguides ( 10, 20). In other words, the center of the diffuser (40) is at a point defined by the coordinates dx and dy, such that dx ^ dy and dx, dy ^ 0. Said asymmetry in the positioning of the diffuser (40) is fundamental in the operation of the device as will be shown below.
    According to the preferred embodiment of the present invention shown in Figures 1 and 2, the diffuser (40) is located on the waveguides (10, 20). Throughout the memory the term "over" may be interpreted both by "above" and "below." It is also envisioned that in an alternative embodiment the diffuser (40) can be located within the zone of intersection between the two waveguides (10, 20), penetrating partially or totally, for example by creating a circular section hole that completely crosses the waveguides (10, 20) in the required position.
    In the event that the diffuser (40) is located within the area of intersection between the two waveguides (10, 20), partially or totally penetrating, the diffuser material must be different than that of the waveguides . In this way there is the necessary discontinuity so that the diffuser can develop its function properly.
    In the event that the diffuser (40) is placed on the waveguides (10, 20), the surrounding air itself causes the necessary discontinuity (air-material of the diffuser), so that the diffuser in this case, it can be of any material, conductor, semiconductor, dielectric, etc., being able to be of the same material as the waveguides
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    (10, 20).
    Although not shown in the figures, the device also comprises a sensor for measuring the power of an output beam arranged in each of the four output ports of the waveguides. Said sensor may be any sensor known and commonly used in the art for this purpose and therefore will not be further described herein.
    Although not shown in the accompanying figures, the device of the present invention may further comprise, in a preferred embodiment thereof, calculation means for determining the polarization state of the incident beam (50) as described hereinbefore. . Specifically, the state of polarization
    is determined by calculating the Stokes vector S from the inverse of the polarimetric measurement matrix
    W and the power vector P, determined in turn by the sensors, according to the following equation:
    image6
    According to another alternative embodiment not shown in the attached figures, the device further comprises connection means with an external calculation device to send the power values detected by the sensors to said external calculation device. In this case, said external calculation device, for example a computer, performs the final calculations for determining the polarization state of the incident beam (50) as described hereinbefore.
    Specifically, when a monochromatic electromagnetic wave (with an X-wavelength) has an impact -z on the intersection that contains the diffuser (40), this
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    It will act as such, spreading part of the electromagnetic radiation that affects it in all directions. Part of the electromagnetic radiation that diffuses will be coupled to waveguide modes (10, 20) (note that the guides can be multimodal) located under the diffuser (40). Said electromagnetic radiation is detected at the output of the waveguides (10, 20), in each of the four output ports (1, 2, 3, 4) to which the electromagnetic radiation is directed as shown by the arrows of figure 1. For example, the total electromagnetic radiation that is directed towards the + x direction could be detected as power P1 at port 1 (figure 1), and so on for ports 2, 3 and 4.
    It is key that by placing the diffuser (40) asymmetrically with respect to the main axes of symmetry of the z = 0 plane, the diffuser response (40) will depend on the polarization of the incident electromagnetic radiation. This is due to the quantum Hall effect of spin of light, especially, present in the evanescent fields of the proposed structure. In particular, the power guided to each output port will be different depending on whether the polarization of the incident monochromatic electromagnetic radiation is linear horizontal (H), linear vertical (V), linear oblique at 45 ° (45), linear oblique at 135 ° (135), drive right (R) or drive left (L). This is because by placing the diffuser asymmetrically, the interaction between the incident electromagnetic radiation and the waveguides (10, 20) is mediated by the overlapping of the electromagnetic radiation diffused with the electric field components of the guided waves in the x and y directions in the evanescent field region above the waveguides (10, 20). Therefore, the guided power will depend on the polarization of the wave
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    incident (potential polarization is mapped). Furthermore, it is also clear from the asymmetric arrangement of the diffuser (40) that the power guided to each output port will be different and will not be linearly related to each other (this would not happen, for example, in the case dx = dy). Therefore, four independent polarization dependent power measurements are obtained from each other, which is equivalent to having four polarization analyzers running simultaneously and in real time. That is, a Stokes polarimeter is obtained whose active region has a size much smaller than the wavelength (w, h, t, D <A).
    The coefficients bq, i that allow the construction
    The matrix W is obtained in a very simple way (mainly because it is only necessary to measure power, not the phase) for the illumination wavelength bqri as the quotient between the power measured at the seventh output port (from 1 to 4) when an ideal polarization electromagnetic radiation beam i (again, i can be H, V, 45, 135, R and L, following the nomenclature of the
    definition of Stokes parameters) and the power density of the incident wave. The obtaining of the matrix
    W for wavelength A is equivalent to calibrating the Stokes polarimeter. Once calibrated, it would allow the immediate obtaining of the EDP of any incident electromagnetic radiation beam by applying equation (8) above. As mentioned earlier, asymmetry
    The device is what makes W invertible.
    Throughout the previous description it has been considered that the EDP is measured for a certain wavelength of the incident beam (50), which is the length
    waveform for which the matrix W is determined. Without
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    However, the device of the present invention can be easily extended to the determination of the EDP in
    multiple wavelengths, since as long as the waveguides are not cut, the device will work. Thus, if the optical spectrum is measured in the four ports
    Output, it will be easy to determine the matrix W for a certain spectral range, which makes it possible for the
    device works as a spectropolar ^ meter.
    In a practical example of realization for the measurement with an incident beam (50) at a wavelength of 1550 nm (corresponding to the band of third window of optical communications), waveguides (10, 20) will be used
    of silicon of dimensions w = 400 nm, t = 250 nm. It should be noted that the length of the waveguides (10, 20) does not imply any limitation in the implementation of the device. The medium (32) above the waveguides (10, 20) is air and the medium (34) below them
    It is s ^ ice dioxide. The diffuser is a gold disc of
    dimensions D = 200 nm and h = 40 nm whose center is located at
    the point defined by the coordinates dx = -50 nm and dy = 100 nm.
    The incident beam (50) can be any electromagnetic radiation whose polarization state must be determined. According to a preferred embodiment of the
    In the present invention, the incident beam (50) is a beam of light.
    According to a second aspect, the present invention discloses a method for measuring the polarization state of an incident beam of electromagnetic radiation comprising the steps of:
    a) having an electromagnetic radiation beam influence a diffuser that preferably has revolution symmetry about an axis corresponding to the direction of propagation of the
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    make;
    b) diffusing the incident beam, by means of said diffuser, along four directions defined by two perpendicular waveguides;
    c) measuring the power of an output beam at each of the four outputs of said two waveguides;
    d) calculate the polarimetric measurement matrix W and the
    power vector P corresponding to the incident beam from the power measured at the waveguide output; Y
    e) calculate the Stokes vector S from the inverse of the polarimetric measurement matrix W and the power vector P calculated in step d),
    the Stokes vector S being representative of the state of polarization of the incident beam.
    The method disclosed by the present invention can be carried out by using a device according to the present invention, as described hereinbefore. Therefore, all the limitations and preferences described above related to the device of the present invention are also applicable to the method according to the second aspect of the present invention.
    In the practical example of embodiment described,
     made an impact  a beam of light on the diffuser, which
     spread the  incident to the four exits
     defined by  The waveguides. The power was measured in
    each of the mentioned outputs when the device was illuminated with light of a wavelength of 1550 nm, a power density of 1 mW / pm2 and six different EDPs, corresponding to horizontal linear polarization, vertical linear polarization, oblique linear polarization to
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    45 °, linear polarization oblique to 135 °, circular polarization to the right and circular polarization to the left. The coefficients bq, i at each output port (q) were determined for the six polarization states (i) and
    I configure the polarimetric measurement matrix W by the appropriate combination of said coefficients, as detailed at the beginning of the present document, the polarimetric measurement matrix being as follows
    W
     (W, H + W, V  W, H ~ W, V £ * 1.45 - £ * 1,135 £ * l, fi - £ * 1, L ^
     ^ 2, H + ^ 2, V  £ * 2, H ~ ^ 2, V £ * 2.45 - £ * £ 2,135 * 2, R _ £ * 2, L
     ^ 3, H +  £ * 3, H ~ b3, V £ * 3.45 - £ * 3.13 £ 5 * 3, fi _ £ * 3, L
      ^ 4, H + ^ 4, V  £ * 4, h ~ byv £ * 4.45 _ £ * £ 4,135 * 4, fi - Kl
    The result of the combinations, represented in magnitudes of effective area (pm), was the following:
    /58.16 —57.98 4.43 2.34
    W = m-3 I 63.47 60.74 -18.85 1.23
    167.66 -63.33 -22.94 -4.18 1
    '53 .02 52.56 -6.82 -2.74 /
    Once the polarimetric measurement matrix was calculated, the power in each of the outputs was measured for an incident beam with any polarization state, from which, and together with the inverse of the matrix of
    Polarimetric measurement W, the Stokes vector representative of the polarization state of the incident beam could be calculated.
    For example, we consider incidence with linear polarization at 50 ° with respect to the x-axis. For this incident beam and the configuration described, the result of the power received at the outputs taking two decimals was (in mW):
    image7
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    From the power measured at the four outputs
    for the light beam with linear polarization at 50 ° (P50) and the
    Inverse of the polarimetric measurement matrix W, the Stokes vector representative of the polarization state of the incident beam (in mW / pm2) could be calculated
    image8
    which fits very well to the Stokes vector representative of a beam of light with an ideal linear polarization state with an inclination of 50 degrees, with minimal differences due to truncating the calculations to two decimal places as well as to small instabilities in the reconstruction of the
    Stokes vector S by the measurement matrix
    polarimetric W. These instabilities can be corrected by conditioning the polarimetric measurement matrix. In the preferred configuration studied as an example we have a matrix conditioning number of k = 41.5, the conditioning number being
    optimal k ° p * ~~ ^ 20 ^
    As can be seen from the previous description, the present invention, and in particular the preferred embodiment thereof, provides a series of advantages over the devices known in the prior art, such as for example:
    - It allows to obtain the four parameters of Stokes.
    - The device is of universal application: in spite of the great interest of the EDP measurement of light, the device of the present invention can be applied to any frequency of the electromagnetic radiation under consideration.
    - The size of the active region in which the
    polarization is less than the incident wavelength (miniaturization of the measuring device).
    - It can be used to measure EDP in a huge spectral range, therefore its use is feasible in
    5 spectropolarimetry.
    - It can be manufactured using standard silicon micro-manufacturing technology, thus avoiding the inclusion of nanostructured metals, which will result in a low cost of large-scale manufacturing.
    10 - It does not need mechanical components, and allows for
    both EDP measurement in real time.
    - Allows the measurement of the EDP of light that propagates in free space as well as light within an optical fiber in online configuration.
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    权利要求:
    Claims (13)
    [1]
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    Device for measuring the polarization state of an incident beam (50) of electromagnetic radiation comprising:
    - two waveguides (10, 20) perpendicular to each other ^
    and perpendicular to the direction of propagation of the incident beam (50), formed by materials
    dielectrics or semiconductors that intersect in an intersection zone whose center represents an origin of coordinates on which the incident beam (50) falls;
    - two means (32, 34), also dielectric or
    semiconductors, which cover above and below said waveguides (10, 20) in such a way
    that its refractive indexes to the wavelength of the incident beam (50) are smaller than the refraction indexes of the waveguides (10, 20);
    - a diffuser (40) of the incident beam (50) located in
    the intersection zone of the waveguides (10, 20) and offset with respect to the origin of
    coordinates in different magnitudes with respect to each of the longitudinal axes of the waveguides (10, 20); Y
    - a sensor to measure the power of a beam of
    output arranged in each of the four output ports (1, 2, 3, 4) of the waveguides (10,
    twenty) .
    Device according to claim 1, characterized in that the diffuser (40) is located on the waveguides (10, 20).
    Device according to claim 1, characterized in that the diffuser (40) is located within the area of
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    [7]
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    [8]
    8.
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    [9]
    9.
    intersection between the two waveguides (10, 20). Device according to claim 3, characterized in that the diffuser (40) is of a material other than the waveguides (10, 20).
    Device according to any of the preceding claims, characterized in that the diffuser (40) of the incident beam (50) has revolution symmetry about an axis corresponding to the direction of propagation of the incident beam (50).
    Device according to any of the preceding claims, characterized in that it further comprises calculation means for determining the polarization state of the incident beam (50) by means of the
    Stokes vector calculation S from the inverse
    of the polarimetric measurement matrix W and the vector
    of power P, determined in turn by the sensors, according to the following equation:
    image 1
    Device according to any one of claims 1 to 5, characterized in that it further comprises connection means with an external calculation device to send the power values detected by the sensors to said external calculation device. Device according to any of the preceding claims, characterized in that the diffuser (40) is of a material selected from the group comprising gold and aluminum.
    Device according to any of the preceding claims, characterized in that the waveguides (10, 20) are made of a transparent material at the wavelength of the incident beam (50).
    5
    10
    fifteen
    twenty
    25
    30
    [10]
    10. Device according to any of the claims
    above, characterized in that the waveguides
    (10, 20) are of a material selected from the group comprising silicon and silicon nitride.
    [11]
    11. Device according to any of the claims
    above, characterized in that the means (32) that
    Overlay the waveguides (10, 20) is air.
    [12]
    12. Device according to any of the claims
    above, characterized in that the medium (34) that
    cover below the waveguides (10, 20) is
    s ^ ice dioxide.
    [13]
    13. Device according to any of the claims
    above, characterized in that the diffuser (40) is a cylinder whose diameter D and height h are smaller than the wavelength of the incident beam (50).
    [14]
    14. Device according to any of the claims
    above, characterized in that the waveguides
    (10, 20) have a rectangular section whose
    width w and height t are less than the wavelength of the incident beam (50).
    [15]
    15. Device according to any of the claims
    above, characterized in that the incident beam (50) is a beam of light.
    [16]
    16. Method for measuring the polarization state of an incident beam of electromagnetic radiation comprising the steps of:
    a) make an electromagnetic radiation beam strike a diffuser;
    b) diffusing the incident beam, by means of said diffuser, along four directions defined by two perpendicular waveguides;
    c) measuring the power of an output beam at each of the four outputs of said two waveguides;
    10
    fifteen
    d) calculate the polarimetric measurement matrix W and the
    power vector P corresponding to the incident beam from the power measured at the waveguide output; Y
    e) calculate the Stokes vector S from the inverse of the polarimetric measurement matrix W and the power vector P calculated in step d),
    the Stokes vector S being representative of the state of polarization of the incident beam.
    [17]
    17. Method according to claim 16, characterized in that the incident beam is a beam of light.
    [18]
    18. Method according to any of claims 16 and 17, characterized in that it is carried out by using a device according to any one of claims 1 to 15.
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    同族专利:
    公开号 | 公开日
    ES2566684B2|2016-09-26|
    WO2017137646A1|2017-08-17|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US7158231B1|1995-09-20|2007-01-02|J.A. Woollam Co., Inc.|Spectroscopic ellipsometer and polarimeter systems|
    US6211957B1|2000-03-03|2001-04-03|Lucent Technologies, Inc.|In-line all-fiber polarimeter|
    US7327456B1|2000-03-21|2008-02-05|J.A. Woollam Co., Inc.|Spectrophotometer, ellipsometer, polarimeter and the like systems|
    JP2010263021A|2009-04-30|2010-11-18|Panasonic Corp|Polarization plane detection sensor, semiconductor integrated circuit and method of controlling the polarization plane detection sensor|
    CN106768345B|2016-11-23|2018-04-06|上海理工大学|Method based on surface plasma direct measurement vertically polarized light polarization state|
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    PCT/ES2017/070067| WO2017137646A1|2016-02-11|2017-02-06|Device and method for measuring the polarisation state of an incident beam|
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