Raster Diffraction Efficiency Testing Device and Method

Abstract

The present invention provides a grating diffraction efficiency testing device and method, which relates to the field of grating diffraction efficiency measurement and is designed to solve the problem that the scanning range of the existing grating diffraction efficiency is limited. The grating diffraction efficiency testing device includes a light source, a measuring head, a moving component, and a sample stage for placing the grating to be tested; the measuring head is installed on the moving component, and the moving component is used to drive the measuring head to linearly move in a plane parallel to the grating to be tested. The sample stage has at least a first position and a second position, and there is a phase difference around the Z-axis between the first position and the second position, and the Z-axis is perpendicular to the grating to be tested; the measuring head is used to receive the light beam emitted by the light source and irradiate the light beam to the grating to be tested at a set angle, and receive the light beam diffracted and returned by the grating to be tested. The present invention can realize the full-area diffraction efficiency test of the grating to be tested, and effectively solves the problem that the scanning range of the existing testing device is limited.

Description

Technical Field

[0001] The present invention relates to the field of grating diffraction efficiency measurement. Specifically, it relates to a grating diffraction efficiency test device and method. Background Technique

[0002] One of the important technical indicators of a grating is the diffraction efficiency, and the grating diffraction efficiency is closely related to the groove type and surface material of the grating. Among them, the grating diffraction efficiency is further divided into absolute diffraction efficiency and relative diffraction efficiency. Through theoretical calculation, the absolute diffraction efficiency of the grating under different groove types and surface materials can be obtained. However, in actual measurement, the grating diffraction efficiency usually refers to the relative diffraction efficiency, that is, the ratio of the diffracted light flux received by the detector at a specific order and wavelength to the reflected light flux of the standard mirror. The diffraction efficiency of the grating is different for different wavelengths and different orders of the same wavelength. Some specific systems (such as precision displacement measurement systems) have specific requirements for the diffraction efficiency of different polarization states of a certain order of a certain wavelength of the grating. Therefore, accurately measuring the relative diffraction efficiency of the grating has a very important guiding role in improving the grating manufacturing technology and the application of the grating.

[0003] Currently, the grating diffraction efficiency test devices at home and abroad generally adopt the structure form of a monochromator. Since most monochromators ensure the monochromaticity of the light beam incident on the grating to be measured through the entrance slit and the mirror group, the scanning range of the test device is limited due to the limited fixed positions of the optical elements. Summary of the Invention

[0004] The first object of the present invention is to provide a grating diffraction efficiency test device to solve the technical problem of the limited scanning range of the existing grating diffraction efficiency.

[0005] The grating diffraction efficiency test device provided by the present invention includes a light source, a measuring head, a moving component, and a sample stage. Among them, the sample stage is used to place the grating to be measured; the measuring head is installed on the moving component, and the moving component is used to drive the measuring head to linearly move in the parallel plane of the grating to be measured. The sample stage has at least a first position and a second position, and there is a phase difference around the Z-axis between the first position and the second position. The Z-axis is perpendicular to the grating to be measured; the measuring head is used to receive the light beam emitted by the light source and irradiate the light beam to the grating to be measured at a set angle, and receive the light beam diffracted and returned by the grating to be measured.

[0006] Further, the sample stage includes a turntable, and the turntable has a degree of freedom of rotation around the Z-axis, and the turntable is configured to place the grating to be measured.

[0007] Further, the turntable is provided with a clamping component, and the clamping component is used to fix the grating to be measured on the turntable.

[0008] Further, the phase difference between the first position and the second position is 90°.

[0009] Further, the moving component is used to drive the measuring head to move in the X direction and the Y direction, both the X direction and the Y direction being parallel to the grating to be measured; the moving component includes a first linear module, a second linear module and an adapter. The first linear module extends in the X direction, the fixed part of the second linear module is fixedly connected to the power output end of the first linear module, and the second linear module extends in the Y direction. The adapter is fixedly connected to the power output end of the second linear module, and the measuring head is fixedly connected to the adapter. The adapter is configured to irradiate the light beam emitted by the mirror group onto the grating to be measured at the set angle.

[0010] Further, the number of the first linear modules is two, and the two first linear modules are arranged at intervals in the Y direction. The fixed part of the second linear module is slidably connected to the power output ends of the two first linear modules at the same time.

[0011] Further, the grating diffraction efficiency testing device further includes a transmission optical fiber, which connects the light source and the measuring head, and is used to guide the light beam emitted by the light source to the measuring head.

[0012] Further, the grating diffraction efficiency testing device further includes a power meter head and a computer. The measuring head is electrically connected to the power meter head, and the power meter head is electrically connected to the computer.

[0013] Further, the measuring head includes a receiving part, a beam splitting box and a light energy detection part. The receiving part is used to receive the light beam emitted by the light source. A mirror group is arranged inside the beam splitting box, and the mirror group is used to irradiate the light beam received by the receiving part onto the grating to be measured at a set angle. The light energy detection part is used to receive the light beam diffracted and returned by the grating to be measured.

[0014] Further, the lens group includes a first polarization beam splitter prism, a second polarization beam splitter prism, and a beam splitter prism. The light energy detection unit includes a first light energy detector, a second light energy detector, and a third light energy detector. Among them, the first polarization beam splitter prism is configured to split the light beam received by the receiving unit into a P-polarized light beam and an S-polarized light beam; the beam splitter prism can split the P-polarized light beam. The linearly transmitted light beam of the P-polarized light beam after being split by the beam splitter prism is incident on the first light energy detector, and the reflected light of the P-polarized light beam after being split by the beam splitter prism is incident on the grating under test at the set angle. The second light energy detector is configured to receive the P-polarized light beam diffracted and returned by the grating under test; the beam splitter prism can also split the S-polarized light beam. The linearly transmitted light beam of the S-polarized light beam after being split by the beam splitter prism is incident on the first light energy detector, and the reflected light of the S-polarized light beam after being split by the beam splitter prism is incident on the grating under test at the set angle. The third light energy detector is configured to receive the S-polarized light beam diffracted and returned by the grating under test.

[0015] Further, the receiving unit includes a collimator, and the collimator is configured to collimate the light beam emitted by the light source into a parallel light beam.

[0016] The beneficial effects brought by the grating diffraction efficiency testing device of the present invention are:

[0017] By providing a grating diffraction efficiency testing device mainly composed of a light source, a measurement head, a moving component, and a sample stage, when it is necessary to test the diffraction efficiency of a one-dimensional planar grating, the grating under test can be placed on the sample stage, and the sample stage is in the first position; the light beam emitted by the light source is incident through the measurement head, and the received light beam is irradiated on the grating under test at a set angle, and then the measurement head is used to receive the light beam diffracted and returned by the grating under test, and the diffraction efficiency of the grating under test is calculated; the moving component is used to linearly move the measurement head in the parallel plane of the grating under test for scanning to achieve the full-area diffraction efficiency test of the grating under test. When it is necessary to test the diffraction efficiency of a two-dimensional planar grating, the sample stage can be used to place the grating under test in a second position with a phase difference from the first position around the Z-axis, and the diffraction efficiency of the grating under test in another grating line direction can be tested.

[0018] The grating diffraction efficiency testing device can achieve the full-area diffraction efficiency test of the grating under test by moving the measurement head, effectively solving the problem of limited scanning range of the existing testing device. Moreover, in this process, it is the measurement head that moves, and there is no need for the grating under test to move. The movement flexibility is good, avoiding problems such as high load requirement for the displacement stage, high test time cost, poor test repeatability and reproducibility caused by repeatedly moving the grating, and reducing the potential safety hazards existing in the test process.

[0019] In addition, by providing the sample stage with a first position and a second position with a phase difference around the Z direction, it is possible to simultaneously meet the test requirements of the diffraction efficiency in multiple grating line directions of a one-dimensional plane grating and a two-dimensional plane grating without moving the grating to be tested.

[0020] The second object of the present invention is to provide a grating diffraction efficiency testing method to solve the technical problem of the limited scanning range of the existing grating diffraction efficiency.

[0021] The grating diffraction efficiency testing method provided by the present invention uses the above-mentioned grating diffraction efficiency testing device to test the diffraction efficiency of the grating to be tested, and comprises the following steps:

[0022] S100: placing the grating to be measured on the sample stage, so that the sample stage is in a first position;

[0023] S200: allowing a light beam emitted by a light source to be incident on a measuring head, and irradiating the received light beam to the grating to be measured at a set angle, and then using the measuring head to receive a light beam diffracted and returned by the grating to be measured, and calculating the diffraction efficiency of the grating to be measured;

[0024] S300: The moving component drives the measuring head to move linearly in a plane parallel to the grating to be measured for scanning;

[0025] S400: Place the sample stage in the second position, and continue to repeat the above steps S200-S300.

[0026] The beneficial effects brought by the grating diffraction efficiency testing method of the present invention are:

[0027] The grating diffraction efficiency testing method utilizes the above-mentioned grating diffraction efficiency testing device to test the diffraction efficiency of the grating to be tested. Accordingly, the grating diffraction efficiency testing method has all the advantages of the above-mentioned grating diffraction efficiency testing device, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0029] Figure 1 A schematic diagram of the structure of a grating diffraction efficiency testing device provided by an embodiment of the present invention;

[0030] Figure 2 A schematic diagram of the structure of a measuring head of a grating diffraction efficiency testing device provided by an embodiment of the present invention after an adapter is installed;

[0031] Figure 3 Schematic diagram of the working principle of the mirror group of the measuring head of the grating diffraction efficiency testing device provided by the embodiment of the present invention;

[0032] Figure 4 Schematic diagram of the two-dimensional scanning path of the grating diffraction efficiency testing device provided by the embodiment of the present invention.

[0033] Description of reference numerals:

[0034] 13 - Light source; 14 - Transmission optical fiber; 15 - Collimator; 16 - Measuring head; 17 - Clamping member; 18 - First optical energy detector; 19 - Second optical energy detector; 20 - Third optical energy detector; 21 - First linear module; 22 - Power meter head; 23 - Drag chain; 24 - Computer; 28 - Second linear module; 26 - Sample stage; 29 - Adapter; 31 - Scanning trajectory; 32 - Grating to be measured; 33 - First polarization beam splitter prism; 34 - Second polarization beam splitter prism; 35 - Beam splitting prism; 36 - Beam splitting box. Detailed implementation manners

[0035] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the following will describe the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Figure 1 Schematic diagram of the structure of the grating diffraction efficiency testing device provided by this embodiment. As Figure 1 shown, this embodiment provides a grating diffraction efficiency testing device, including a light source 13, a measuring head 16, a moving assembly and a sample stage 26. Among them, the sample stage 26 is used to place the grating 32 to be measured; the measuring head 16 is installed on the moving assembly, and the moving assembly is used to drive the measuring head 16 to linearly move in a plane parallel to the grating 32 to be measured. The sample stage 26 has at least a first position and a second position, and there is a phase difference around the Z direction between the first position and the second position, and the Z direction is perpendicular to the grating 32 to be measured; the measuring head 16 is used to receive the light beam emitted by the light source 13 and irradiate the light beam to the grating 32 to be measured at a set angle, and receive the light beam diffracted and returned by the grating 32 to be measured.

[0037] When it is necessary to test the diffraction efficiency of a one-dimensional planar grating, the grating to be tested 32 can be placed on the sample stage 26, and the sample stage 26 is in the first position; the light beam emitted by the light source 13 is incident through the measuring head 16, and the received light beam is irradiated onto the grating to be tested 32 at a set angle, and then the measuring head 16 is used to receive the light beam diffracted and returned by the grating to be tested 32, and the diffraction efficiency of the grating to be tested 32 is calculated; the measuring head 16 is linearly moved in the parallel plane of the grating to be tested by using the moving component for scanning, so as to realize the full-area diffraction efficiency test of the grating to be tested 32. When it is necessary to test the diffraction efficiency of a two-dimensional planar grating, the sample stage 26 can be used to place the grating to be tested 32 in a second position with a phase difference around the Z direction from the first position, and the diffraction efficiency of the grating to be tested 32 in another grating line direction is tested.

[0038] By moving the measuring head 16, the full-area diffraction efficiency test of the grating to be tested 32 can be realized, effectively solving the problem of limited scanning range of the existing test device. Moreover, in this process, it is the measuring head 16 that moves, and there is no need for the grating to be tested 32 to move, so the moving flexibility is good, avoiding problems such as high load-bearing requirements for the displacement stage, high test time cost, poor test repeatability and reproducibility caused by repeatedly moving the grating, and reducing the potential safety hazards in the test process.

[0039] In addition, by making the sample stage 26 have a first position and a second position with a phase difference around the Z direction, it is also possible to meet the test requirements for the diffraction efficiency of multiple grating line directions of one-dimensional and two-dimensional planar gratings without moving the grating to be tested 32.

[0040] Please continue to refer to Figure 1 , in this embodiment, the sample stage 26 includes a turntable, the turntable has a degree of freedom of rotation around the Z direction, and the turntable is configured to place the grating to be tested 32. That is to say, the turntable can rotate 360° around the Z direction.

[0041] When testing the diffraction efficiency of the grating to be tested 32, the direction of different grating lines of the grating to be tested 32 and the incident light relative to the grating lines can be changed by rotating the turntable. This form of using the turntable to realize the switching between the first position and the second position of the grating to be tested 32 has a simple structure and is easy to implement.

[0042] Please continue to refer to Figure 1 , in this embodiment, the turntable is provided with a clamping member 17, and the clamping member 17 is used to fix the grating to be tested 32 on the turntable.

[0043] By providing the clamping member 17 on the turntable, the effective fixation of the grating to be tested 32 can be realized, preventing the grating to be tested 32 from shifting during the test, thus ensuring the accuracy of the test.

[0044] Specifically, in this embodiment, the clamping member 17 can be a stress-free fixture. With this arrangement, damage to the grating under test 32 during the clamping process can be effectively avoided.

[0045] It should be noted that in this embodiment, the grating under test 32 is horizontally placed on the sample stage 26, and the sample stage 26 is located below the measuring head 16. It can be understood that during actual use, the sample stage 26 can also be placed vertically so that the grating under test 32 is placed perpendicular to the horizontal plane.

[0046] In other embodiments, a fixture having only a first position and a second position can also be set according to the shape of the grating under test 32 to fix the grating under test 32 rotated to the required position.

[0047] In this embodiment, the phase difference between the first position and the second position is 90°. With this arrangement, the test requirements for the diffraction efficiencies of two mutually perpendicular grating line directions of a two-dimensional planar grating are met.

[0048] Figure 2 It is a schematic structural diagram of the measuring head 16 of the grating diffraction efficiency testing device provided in this embodiment after installing the adapter 29. Please continue to refer to Figure 1 and in combination with Figure 2 In this embodiment, the moving assembly is used to drive the measuring head 16 to move in the X direction and the Y direction, and both the X direction and the Y direction are parallel to the grating under test 32; the moving assembly can include a first linear module 21, a second linear module 28, and an adapter 29. Specifically, the first linear module 21 extends in the X direction, the fixed part of the second linear module 28 is fixedly connected to the power output end of the first linear module 21, and the second linear module 28 extends in the Y direction. The adapter 29 is fixedly connected to the power output end of the second linear module 28, and the measuring head 16 is fixedly connected to the adapter 29. The adapter 29 is configured to make the light beam emitted by the lens group irradiate the grating under test 32 at a set angle.

[0049] When the grating diffraction efficiency testing device works, the first linear module 21 works to drive the second linear module 28 to move in the X direction to realize the scanning of the light beam in the X direction; at the same time, the second linear module 28 works to drive the adapter 29 to drive the measuring head 16 to move in the Y direction to realize the scanning of the light beam in the Y direction. Through the movement of the first linear module 21 and the second linear module 28, the purpose of two-dimensional full-frame scanning of the grating under test 32 by the measuring head 16 in the X direction and the Y direction can be achieved.

[0050] It should be noted that in this embodiment, the grating is a large-size grating, where the large-size grating can be a grating with a diagonal size reaching the meter level; the Z direction is perpendicular to both the X direction and the Y direction at the same time.

[0051] Please continue to refer to Figure 1, in this embodiment, the moving component may further include a drag chain 23. The drag chain 23 can hide and protect the wire harnesses of the first linear module 21 and the second linear module 28, preventing the situation where the moving component cannot work properly due to the wire harnesses being entangled or damaged.

[0052] In this embodiment, the set angle is the Littrow angle. On the one hand, the adapter 29 serves to connect the measuring head 16 and the second linear module 28. On the other hand, it also causes the light beam to irradiate the grating under test 32 at the set angle, so as to form an effective diffraction at the grating lines of the grating under test 32.

[0053] Please continue to refer to Figure 1 , in this embodiment, the number of the first linear modules 21 is two. The two first linear modules 21 are arranged at intervals along the Y direction. The fixed part of the second linear module 28 is slidably connected to the power output ends of the two first linear modules 21 at the same time.

[0054] With such a setting, the two first linear modules 21 can support the second linear module 28, making the force balance of the second linear module 28 better, so that its movement is more stable.

[0055] It should be noted that, in this embodiment, the two first linear modules 21 and one second linear module 28 form an H-shaped layout structure to realize the two-dimensional scanning of the measuring head 16. It can be understood that an L-shaped layout structure can also be adopted with one first linear module 21 and one second linear module 28, which can also achieve the purpose of two-dimensional scanning of the measuring head 16.

[0056] In this embodiment, the measuring head 16 includes a receiving part, a beam splitting box 36 and a light energy detecting part. The receiving part is used to receive the light beam emitted by the light source 13. A mirror group is arranged inside the beam splitting box 36, and the mirror group is used to irradiate the light beam received by the receiving part to the grating under test 32 at a set angle. The light energy detecting part is used to receive the light beam diffracted and returned by the grating under test 32.

[0057] Please continue to refer to Figure 1 , in this embodiment, the grating diffraction efficiency testing device may further include a transmission optical fiber 14. Specifically, the transmission optical fiber 14 connects the light source 13 and the receiving part, and the transmission optical fiber 14 is used to guide the light beam emitted by the light source 13 to the receiving part.

[0058] By setting the transmission optical fiber 14, the light beam emitted by the light source 13 is transported to the receiving part of the measuring head 16 by using the transmission optical fiber 14, so that the light beam emitted by the light source 13 can be utilized as much as possible, effectively solving the problem of low utilization rate of the light beam caused by the transmission method of coupling spatial light into the optical fiber in the prior art.

[0059] Please continue to refer to Figure 1, in this embodiment, the grating diffraction efficiency testing device may further include a power meter head 22 and a computer 24. Specifically, the optical energy detection unit is electrically connected to the power meter head 22, and the power meter head 22 is electrically connected to the computer 24.

[0060] During the operation of the grating diffraction efficiency testing device, the optical energy detection unit feeds back the received beam signal to the power meter head 22. The power meter head 22 serves as an interface to provide communication between the optical energy detection unit and the computer 24 or other external control devices, enabling the computer 24 to process the received information in a timely manner and automatically obtain the diffraction efficiency of the grating 32 to be measured.

[0061] Please continue to refer to Figure 2 , in this embodiment, the receiving unit includes a collimator 15, and the collimator 15 is used to collimate the beam emitted by the light source 13 into a parallel beam. With such a setting, the beam emitted by the light source 13 can enter the beam splitting box 36 as much as possible to participate in the diffraction test of the grating 32 to be measured.

[0062] Figure 3 It is a schematic diagram of the working principle of the lens group of the measuring head 16 of the grating diffraction efficiency testing device provided in this embodiment. Please continue to refer to Figure 2 , and in combination with Figure 3 , in this embodiment, the lens group may include a first polarization beam splitter prism 33, a second polarization beam splitter prism 34, and a beam splitting prism 35. The optical energy detection unit includes a first optical energy detector 18, a second optical energy detector 19, and a third optical energy detector 20. Specifically, the first polarization beam splitter prism 33 is used to split the beam received by the collimator 15 into a P-polarized light and an S-polarized light; the beam splitting prism 35 can split the P-polarized light. The linearly transmitted beam of the P-polarized light after being split by the beam splitting prism 35 is incident on the first optical energy detector 18, and the reflected light of the P-polarized light after being split by the beam splitting prism 35 is incident on the grating 32 to be measured at the Littrow angle. The second optical energy detector 19 is configured to receive the P-polarized light diffracted back by the grating 32 to be measured; the beam splitting prism 35 can also split the S-polarized light. The linearly transmitted beam of the S-polarized light after being split by the beam splitting prism 35 is incident on the first optical energy detector 18, and the reflected light of the S-polarized light after being split by the beam splitting prism 35 is incident on the grating 32 to be measured at the Littrow angle. The third optical energy detector 20 is configured to receive the S-polarized light diffracted back by the grating 32 to be measured.

[0063] During the operation of the grating diffraction efficiency test device, the light beam emitted by the light source 13 is input into the measuring head 16 through the transmission optical fiber 14. After being collimated by the collimator 15, it becomes a parallel light beam. This parallel light beam is split by the first polarization beam splitter prism 33 to obtain P-polarized light and S-polarized light. Among them, the P-polarized light passes through the beam splitter prism 35, and the light beam that maintains a straight-line transmission is incident into the first light energy detector 18 as the compensation path of the input light beam. The light reflected downward by the P-polarized light through the beam splitter prism 35 is incident on the grating under test 32 at the Littrow angle. After being diffracted by the grating under test 32, it returns to the measuring head 16 along the original path. After passing through the beam splitter prism 35, it is incident upward into the second light energy detector 19 as the light intensity of the diffraction of the P-polarized light by the grating under test 32. The S-polarized light obtained by splitting the incident light beam collimated by the collimator 15 by the first polarization beam splitter prism 33 is reflected by the second polarization beam splitter prism 34. The light reflected downward by it through the beam splitter prism 35 is incident on the grating under test 32 at the Littrow angle. After being diffracted by the grating under test 32, it returns to the measuring head 16 along the original path. After passing through the beam splitter prism 35, it is incident upward into the third light energy detector 20 as the light intensity of the diffraction of the S-polarized light by the grating under test 32.

[0064] As described above, the calculation method of the diffraction efficiency of the grating under test 32 is as follows:

[0065] Denote the output power of the collimator 15 as P0, the power of the compensation path of the input light beam detected by the first light energy detector 18 as P1, and the transmittance of the mirror group of the measuring head 16 to the incident light beam of the collimator 15 as M. Then:

[0066] P0 = P1 / M

[0067] Denote the transmittances of the mirror group of the measuring head 16 to the incident light of the P-polarized light and the S-polarized light as M P and M S , and denote the grating incident powers of the P-polarized light and the S-polarized light as λ P and λ S . Then:

[0068] λ P = P0 * M P = (P1 / M) * M P

[0069] λ S = P0 * M S = (P1 / M) * M S

[0070] Denote the readings of the second light energy detector 19 and the third light energy detector 20 as P2 and P3 respectively, and denote the diffraction efficiencies of the incident light beams of the P-polarized light and the S-polarized light by the grating under test 32 as N P and N S, the diffraction light transmittances of the measuring head 16 for P-polarized light and S-polarized light are respectively denoted as K P and K S , then:

[0071] N P = P2 / K P / λ P = (P2 * M) / (K P * P1 * M P )

[0072] N S = P3 / K S / λ S = (P3 * M) / (K S * P1 * M S )

[0073] wherein, the light transmittance of the lens group of the measuring head 16 for the incident light of the collimator 15 is M, and the incident light transmittances of the lens group of the measuring head 16 for P-polarized light and S-polarized light are respectively M P and M S , and the diffraction transmittances of the measuring head 16 for P-polarized light and S-polarized light are denoted as K P and K S , which are known parameters. According to the values of the first light energy detector 18, the second light energy detector 19, and the third light energy detector 20 recorded by the computer 24 at the same moment, the diffraction efficiencies of the P-polarized light and S-polarized light at the corresponding positions of the grating to be measured 32 can be obtained.

[0074] Figure 4 is a schematic diagram of the two-dimensional scanning path of the grating diffraction efficiency test device provided in this embodiment. As Figure 4 shown, under the action of the moving component, the measuring head 16 performs a full-area scan on the grating to be measured 32, and the scanning trajectory 31 is as shown in the figure, so as to obtain the diffraction efficiencies of the grating to be measured 32 for P-polarized light and S-polarized light at each position.

[0075] This grating diffraction efficiency test device can simultaneously complete the measurement of the diffraction efficiencies of P-polarized light and S-polarized light, and while obtaining the diffraction efficiencies of the grating to be measured 32 for incident light of different polarization states, the test time and test cost are greatly reduced.

[0076] It should be noted that in this embodiment, the relative positions of the P-polarized light and S-polarized light emitted by the measuring head 16 can be changed by changing the combination mode of the lens groups in the measuring head 16.

[0077] In addition, this embodiment also provides a method for testing the diffraction efficiency of a grating, which uses the above grating diffraction efficiency test device to test the diffraction efficiency of the grating to be measured 32, and includes the following steps:

[0078] S100: Place the grating 32 to be measured on the sample stage 26, and position the sample stage 26 at the first position;

[0079] S200: Cause the light beam emitted by the light source 13 to be incident by the measuring head 16, and irradiate the received light beam onto the grating 32 to be measured at a set angle. Then, use the measuring head 16 to receive the light beam diffracted and returned by the grating 32 to be measured, and calculate the diffraction efficiency of the grating 32 to be measured;

[0080] S300: The moving assembly drives the measuring head 16 to linearly move and scan in a parallel plane of the grating 32 to be measured;

[0081] S400: Position the sample stage 26 at the second position, and continue to repeat the above steps S200 - S300.

[0082] This method for testing the diffraction efficiency of a grating uses the above - mentioned device for testing the diffraction efficiency of a grating to test the diffraction efficiency of the grating to be measured. Correspondingly, this method for testing the diffraction efficiency of a grating has all the advantages of the above - mentioned device for testing the diffraction efficiency of a grating, which will not be elaborated one by one here.

[0083] Specifically, in the above step S200, the light beam emitted by the light source 13 is incident through the receiving part of the measuring head 16. The mirror group is used to irradiate the light beam received by the receiving part onto the grating 32 to be measured at a set angle, and the light energy detection part is used to receive the light beam diffracted and returned by the grating 32 to be measured, and calculate the diffraction efficiency of the grating 32 to be measured. In the above step S300, the moving assembly drives the measuring head 16 to perform a step - by - step scan along the X - direction and the Y - direction, and the scanning trajectory is as Figure 4 shown.

[0084] Using this method for testing the diffraction efficiency of a grating, not only can the diffraction efficiency of a one - dimensional planar grating under P - polarized light and S - polarized light be tested, but also the diffraction efficiency of a two - dimensional planar grating under P - polarized light and S - polarized light can be tested. It has a wide range of applications, strong versatility, reduces the test cost of the diffraction efficiency, saves the test time, and the entire test process does not require the grating 32 to be measured to move repeatedly, with good flexibility and further reduced test time.

[0085] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

[0086] Finally, it should also be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0087] In the above embodiments, descriptions of orientations such as "upper" and "lower" are all based on the figures shown.

[0088] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A grating diffraction efficiency testing device, characterized in that It includes a light source (13), a measuring head (16), a moving component, and a sample stage (26). Among them, the sample stage (26) is used to place the grating to be measured (32); the measuring head (16) is installed on the moving component, and the moving component is used to drive the measuring head (16) to linearly move in the parallel plane of the grating to be measured (32). The sample stage (26) has at least a first position and a second position, and there is a phase difference around the Z-axis between the first position and the second position. The Z-axis is perpendicular to the grating to be measured (32); the measuring head (16) is used to receive the light beam emitted by the light source (13) and irradiate the light beam to the grating to be measured (32) at a set angle, and receive the light beam diffracted and returned by the grating to be measured (32); the grating diffraction efficiency testing device further includes a power meter head (22) and a computer (24). The measuring head (16) is electrically connected to the power meter head (22), and the power meter head (22) is electrically connected to the computer (24); the measuring head (16) includes a receiving part, a beam splitting box (36), and a light energy detecting part. The receiving part is used to receive the light beam emitted by the light source (13). A mirror group is arranged inside the beam splitting box (36), and the mirror group is used to irradiate the light beam received by the receiving part to the grating to be measured (32) at a set angle. The light energy detecting part is used to receive the light beam diffracted and returned by the grating to be measured (32); the mirror group includes a first polarization beam splitting prism (33), a second polarization beam splitting prism (34), and a beam splitting prism (35). The light energy detecting part includes a first light energy detector (18), a second light energy detector (19), and a third light energy detector (20). Among them, the first polarization beam splitting prism (33) is used to split the light beam received by the receiving part to obtain P-polarized light and S-polarized light; the beam splitting prism (35) can split the P-polarized light. The linearly transmitted light beam of the P-polarized light after being split by the beam splitting prism (35) is incident on the first light energy detector (18). The reflected light of the P-polarized light after being split by the beam splitting prism (35) is incident on the grating to be measured (32) at the set angle. The second light energy detector (19) is configured to receive the P-polarized light diffracted and returned by the grating to be measured (32); the beam splitting prism (35) can also split the S-polarized light. The linearly transmitted light beam of the S-polarized light after being split by the beam splitting prism (35) is incident on the first light energy detector (18). The reflected light of the S-polarized light after being split by the beam splitting prism (35) is incident on the grating to be measured (32) at the set angle. The third light energy detector (20) is configured to receive the S-polarized light diffracted and returned by the grating to be measured (32).

2. The grating diffraction efficiency testing device according to claim 1, wherein The sample stage (26) includes a turntable, the turntable has a degree of freedom of rotating around the Z-axis, and the turntable is configured to place the grating to be measured (32).

3. The grating diffraction efficiency testing device according to claim 2, characterized in that, The turntable is provided with a clamping member (17) for fixing the grating to be measured (32) on the turntable.

4. The grating diffraction efficiency testing device according to claim 1, wherein The phase difference between the first position and the second position is 90°.

5. The grating diffraction efficiency testing device according to claim 1, wherein The moving assembly is used to drive the measuring head (16) to move along the X direction and the Y direction, both the X direction and the Y direction being parallel to the grating to be measured (32); the moving assembly includes a first linear module (21), a second linear module (28) and an adapter (29), the first linear module (21) extends along the X direction, the fixed part of the second linear module (28) is fixedly connected to the power output end of the first linear module (21), and the second linear module (28) extends along the Y direction, the adapter (29) is fixedly connected to the power output end of the second linear module (28), the measuring head (16) is fixedly connected to the adapter (29), and the adapter (29) is configured to irradiate the light beam emitted by the lens group to the grating to be measured (32) at the set angle.

6. The grating diffraction efficiency testing device according to claim 5, characterized in that The number of the first linear modules (21) is two, and the two first linear modules (21) are arranged at intervals along the Y direction, and the fixed part of the second linear module (28) is slidably connected to the power output ends of the two first linear modules (21) at the same time.

7. The grating diffraction efficiency testing device according to claim 1, characterized in that The grating diffraction efficiency testing device further includes a transmission optical fiber (14) connecting the light source (13) and the measuring head (16), and the transmission optical fiber (14) is used to guide the light beam emitted by the light source (13) to the measuring head (16).

8. The grating diffraction efficiency testing device according to claim 1, wherein The grating diffraction efficiency testing device further includes a power meter head (22) and a computer (24), the measuring head (16) is electrically connected to the power meter head (22), and the power meter head (22) is electrically connected to the computer (24).

9. The grating diffraction efficiency testing device according to claim 1, wherein The receiving part includes a collimator (15) for collimating the light beam emitted by the light source (13) into a parallel light beam.

10. A method for testing the diffraction efficiency of a grating, characterized in that, Testing the diffraction efficiency of the grating to be measured (32) by using the grating diffraction efficiency testing device according to any one of claims 1-9, comprising the following steps: S100: Place the grating to be measured (32) on the sample stage (26) to make the sample stage (26) in the first position; S200: Make the light beam emitted by the light source (13) enter through the measuring head (16), irradiate the received light beam to the grating to be measured (32) at a set angle, and then use the measuring head (16) to receive the light beam diffracted and returned by the grating to be measured (32), and calculate the diffraction efficiency of the grating to be measured (32); S300: The moving assembly drives the measuring head (16) to linearly move and scan in the parallel plane of the grating to be measured (32); S400: Make the sample stage (26) in the second position, and continue to repeat the above steps S200-S300.

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