Grating diffraction efficiency measuring system and method

Abstract

The embodiment of the invention provides a grating diffraction efficiency system and method, and the system measures a first energy value obtained by a first energy meter when a first laser beam enters a to-be-measured grating, and also measures a second energy value obtained by reflecting the first laser beam to a second energy meter. And meanwhile, a third energy value obtained by the first energy meter when the second laser beam enters the high-reflectivity plane mirror is measured, and a fourth energy value obtained by reflecting the second laser beam to the second energy meter is also measured. And respectively converting the second energy value and the fourth energy value obtained by the second energy meter into a fifth energy value and a sixth energy value according to a predetermined energy conversion relation of the energy values. According to the difference between the fifth energy value and the sixth energy value, the output energy value difference between the laser beam incident to the to-be-measured grating and the laser beam incident to the high-reflectivity plane mirror is determined, and therefore the accuracy of calculating the grating diffraction efficiency of the to-be-measured grating is improved.

Description

Technical Field

[0001] This application relates to the field of optical measurement technologies, and particularly relates to a grating diffraction efficiency measurement system and method. Background Art

[0002] Echelle gratings are a special type of grating, characterized by a low groove density, large incident angles, and high diffraction orders. Therefore, they have a high dispersion rate and resolution. In the field of semiconductor lithography, gratings play a crucial role in compressing the linewidth of lasers and enhancing energy.

[0003] The grating diffraction efficiency is one of the important performance indicators of echelle gratings. However, in the prior art when measuring the grating diffraction efficiency, a laser beam is respectively incident on the grating to be measured and a highly reflective flat mirror, and the ratio between the energy value returned by the grating to be measured and the energy value returned by the highly reflective flat mirror is used as the grating diffraction efficiency of the grating. However, the accuracy of the grating diffraction efficiency measured by the above prior art is relatively low.

[0004] Therefore, how to improve the accuracy of the measurement result of the grating diffraction efficiency is a technical problem to be solved. Summary of the Invention

[0005] Embodiments of this application provide a grating diffraction efficiency measurement system to improve the accuracy of the measurement result of the grating diffraction efficiency. Embodiments of this application are also related to a grating diffraction efficiency measurement method.

[0006] Embodiments of this application provide a grating diffraction efficiency measurement system, including: a laser energy measurement device, and a grating diffraction efficiency analysis device; the laser energy measurement device is used to record a first energy value of a diffracted beam generated by the grating to be measured for a first laser beam incident on a first energy meter, and record a second energy value of the first laser beam reflected to a second energy meter; record a third energy value of a reflected beam generated by the highly reflective flat mirror for a second laser beam incident on the first energy meter, and record a fourth energy value of the second laser beam reflected to the second energy meter; the grating diffraction efficiency analysis device is used to convert the second energy value obtained by the second energy meter into a fifth energy value and convert the fourth energy value obtained by the second energy meter into a sixth energy value according to a pre-determined energy conversion relationship for converting the energy value of the second energy meter into the energy value of the first energy meter; obtain the grating diffraction efficiency of the grating to be measured according to the first energy value, the third energy value, the fifth energy value, and the sixth energy value.

[0007] Optionally, the grating diffraction efficiency analysis device is specifically used to obtain the difference between the fifth energy value and the sixth energy value, perform an addition process on the third energy value and the difference to obtain a seventh energy value; use the ratio between the first energy value and the seventh energy value as the grating diffraction efficiency of the grating to be measured.

[0008] Optionally, the laser energy measurement device includes a laser light source, an adjustment component, a beam splitting component, and an optical path collimation component; the adjustment component includes a highly reflective flat mirror, a grating under test, a first energy meter, and a second energy meter; the beam splitting component is disposed in the optical path of the output beam of the laser light source for splitting the output beam into a transmitted beam and a reflected beam; the grating under test is disposed in the first optical path where the transmitted beam is located, the highly reflective flat mirror is disposed in the region between the beam splitting component and the grating under test, and the highly reflective flat mirror can be moved vertically into or out of the first optical path; the second energy meter is disposed in the second optical path where the reflected beam is located; the first energy meter is disposed in the third optical path, and the third optical path is the optical path where the beam returns after the transmitted beam incident on the highly reflective flat mirror or the grating under test is reflected by the beam splitting component again; the optical path collimation component is used to adjust the grating under test to the absolute zero position; the adjustment component is used to rotate the grating under test from the absolute zero position by a preset angle; based on the highly reflective flat mirror moving out of the first optical path, the first laser beam is incident on the grating under test through the transmitted beam after splitting, and the diffracted beam returned through the grating under test is incident on the first energy meter to obtain the first energy value, and the reflected beam after splitting of the first laser beam is incident on the second energy meter to obtain the second energy value; based on the highly reflective flat mirror moving into the first optical path, the second laser beam is incident on the highly reflective flat mirror through the transmitted beam after splitting, and the reflected beam returned through the highly reflective flat mirror is incident on the first energy meter to obtain the third energy value, and the reflected beam after splitting of the second laser beam is incident on the second energy meter to obtain the fourth energy value.

[0009] Optionally, the energy conversion relationship for converting the energy value of the pre-determined second energy meter into the energy value of the first energy meter is obtained in the following manner: Obtain multiple laser beams with known energy values, and the energy values of the multiple laser beams respectively present a preset change relationship. For each laser beam, perform the following operations: Incident the transmitted beam after splitting of the laser beam on the highly reflective flat mirror, and the beam reflected by the highly reflective flat mirror is incident on the first energy meter to obtain the eighth energy value, and incident the reflected beam after splitting of the laser beam on the second energy meter to obtain the ninth energy value; Use the eighth energy value and the ninth energy value as an energy value group of the laser beam; Obtain the energy value groups respectively corresponding to the multiple laser beams, and based on the obtained multiple energy value groups, analyze and obtain the energy conversion relationship for converting the energy value of the second energy meter into the energy value of the first energy meter.

[0010] Optionally, the adjustment component is used to rotate the grating under test by a preset angle from the absolute zero position, specifically, to adjust the turntable carrying the grating under test to rotate the grating under test by a preset angle from the absolute zero position, and the preset angle is the grating blazing angle of the grating under test.

[0011] Optionally, the optical path collimation component is used to adjust the grating under test to the absolute zero position, specifically, to perform preliminary optical path collimation processing on the grating under test; based on the obtained preliminary optical path collimation processing result, perform target optical path collimation processing on the grating under test; based on the obtained target optical path collimation processing result, determine the current position of the grating under test as the absolute zero position.

[0012] The embodiment of the present application also provides a method for measuring the diffraction efficiency of a grating, including: a first laser beam is incident on the grating under test, and a first energy value of the diffracted beam returned by the grating under test and incident on the first energy meter is recorded, and a second energy value of the first laser beam reflected to the second energy meter is recorded; a second laser beam is incident on the high-reflection flat mirror, and a third energy value of the reflected beam returned by the high-reflection flat mirror and incident on the first energy meter is recorded, and a fourth energy value of the second laser beam reflected to the second energy meter is recorded; according to the energy conversion relationship for converting the energy value of the second energy meter to the energy value of the first energy meter determined in advance, convert the second energy value obtained by the second energy meter into a fifth energy value, and convert the fourth energy value obtained by the second energy meter into a sixth energy value; according to the first energy value, the third energy value, the fifth energy value, and the sixth energy value, obtain the diffraction efficiency of the grating under test.

[0013] Optionally, the step of obtaining the diffraction efficiency of the grating under test according to the first energy value, the third energy value, the fifth energy value, and the sixth energy value includes: obtaining the difference between the fifth energy value and the sixth energy value, and adding the third energy value and the difference to obtain a seventh energy value; taking the ratio between the first energy value and the seventh energy value as the diffraction efficiency of the grating under test.

[0014] Optionally, the incident of the first laser beam on the grating to be measured includes: moving the highly reflective flat mirror out of the first optical path, rotating the grating to be measured by a preset angle from the absolute zero position, and making the transmitted beam obtained by splitting the first laser beam by the beam splitting component incident on the grating to be measured; the incident of the second laser beam on the highly reflective flat mirror includes: moving the highly reflective flat mirror into the first optical path, and making the transmitted beam obtained by splitting the second laser beam by the beam splitting component incident on the highly reflective flat mirror; wherein, the first laser beam and the second laser beam are respectively laser beams at two different times emitted by a laser light source, the beam splitting component is arranged in the optical path of the emitted beam of the laser beam and is used for splitting the emitted beam into a transmitted beam and a reflected beam; the grating to be measured is arranged in the first optical path where the transmitted beam is located, the highly reflective flat mirror is arranged in the area between the optical path splitting component and the grating to be measured, and the highly reflective flat mirror can be moved into or out of the first optical path in the vertical direction.

[0015] Optionally, the energy conversion relationship for converting the energy value of the pre-determined second energy meter into the energy value of the first energy meter is obtained in the following manner: obtaining a plurality of laser beams with known energy values, the energy values of the plurality of laser beams respectively presenting a preset change relationship, and performing the following operations for each laser beam: making the transmitted beam after splitting the laser beam incident on the highly reflective flat mirror, making the beam reflected by the highly reflective flat mirror incident on the first energy meter to obtain an eighth energy value, and making the reflected beam after splitting the laser beam incident on the second energy meter to obtain a ninth energy value; taking the eighth energy value and the ninth energy value as an energy value group of the laser beam; obtaining the energy value groups respectively corresponding to the plurality of laser beams, and analyzing and obtaining the energy conversion relationship for converting the energy value of the second energy meter into the energy value of the first energy meter according to the obtained plurality of energy value groups.

[0016] Compared with the prior art, the embodiments of the present application have the following advantages:

[0017] An embodiment of the present application provides a grating diffraction efficiency measurement system, including: a laser energy measurement device and a grating diffraction efficiency analysis device; the laser energy measurement device is used to record a first energy value of a diffracted beam generated by a grating under test for a first laser beam incident on a first energy meter, and record a second energy value of the first laser beam reflected to a second energy meter; record a third energy value of a reflected beam generated by a high-reflection plane mirror for a second laser beam incident on the first energy meter, and record a fourth energy value of the second laser beam reflected to the second energy meter; the grating diffraction efficiency analysis device is used to convert the second energy value obtained by the second energy meter into a fifth energy value and the fourth energy value obtained by the second energy meter into a sixth energy value according to a pre-determined energy conversion relationship for converting the energy value of the second energy meter into the energy value of the first energy meter; and obtain the grating diffraction efficiency of the grating under test according to the first energy value, the third energy value, the fifth energy value and the sixth energy value.

[0018] This system measures the first energy value obtained by the first energy meter when the first laser beam is incident on the grating under test, and also measures the second energy value obtained when the first laser beam is reflected to the second energy meter. At the same time, when measuring the third energy value obtained by the first energy meter when the second laser beam is incident on the high-reflection plane mirror, it also measures the fourth energy value obtained when the second laser beam is reflected to the second energy meter. Here, when the two laser beams are incident on the grating under test or the high-reflection plane mirror, the paths of the two laser beams reflected and incident on the second energy meter are the same. Therefore, the difference between the second energy value and the fourth energy value obtained by the second energy meter is caused by the difference in the output energy values of the two laser beams. According to the pre-determined energy conversion relationship for converting the energy value of the second energy meter into the energy value of the first energy meter, the second energy value obtained by the second energy meter is converted into a fifth energy value, and the fourth energy value is converted into a sixth energy value. According to the fifth energy value and the sixth energy value, the influence of the error between the output energy values of the two laser beams on the grating diffraction efficiency is solved. According to the first energy value, the third energy value, the fifth energy value and the sixth energy value, the grating diffraction efficiency is calculated, improving the measurement accuracy of the grating diffraction efficiency. Description of the Drawings

[0019] Figure 1 It is a logic framework diagram of a grating diffraction efficiency measurement system provided by the first embodiment of the present application.

[0020] Figure 2 It is a schematic diagram of the laser energy measurement device provided by the first embodiment of the present application for measuring the energy value of the diffracted beam of the grating under test.

[0021] Figure 3 It is a schematic diagram of the laser energy measurement device provided by the first embodiment of the present application for measuring the energy value of the reflected beam of the high-reflection plane mirror.

[0022] Figure 4 Schematic diagram for optical path collimation processing of a grating under test provided in the first embodiment of the present application.

[0023] Figure 5 Structural diagram of a grating under test provided in the first embodiment of the present application. Among them, the non-grooved area 101 of the grating under test, the blazed surface 102 of the grooved area of the grating under test, and the engraved part 103 of the grooved area.

[0024] Figure 6 Schematic diagram for rotating the grating under test from the absolute zero position by a preset angle provided in the first embodiment of the present application.

[0025] Figure 7 Process diagram for determining the energy conversion relationship for converting the energy value of the second energy meter to the energy value of the first energy meter provided in the first embodiment of the present application.

[0026] Among them, Figures 2 to 4 , Figure 7 The following reference numerals are included in total:

[0027] Laser 110, highly reflective flat mirror 201, grating under test 202, first energy meter 203, second energy meter 204, first adjustment stage 205, rotating stage 206, second adjustment stage 207, fluorescence prism 208, first fluorescence cross plate 209, first observation window 210, fluorescence mirror 211, second fluorescence cross plate 212, second observation window 213, electric diaphragm 214, adjustable diaphragm 301, semi-transmissive and semi-reflective coated lens 302, beam splitter 303, output beam 401 of the laser light source, first optical path 402, second optical path 403, third optical path 404, fourth optical path 405, fifth optical path 406.

[0028] Figure 8 Schematic diagram of the fitting function for representing the energy conversion relationship for converting the energy value of the second energy meter to the energy value of the first energy meter provided in the first embodiment of the present application.

[0029] Figure 9 Flow schematic diagram of a method for measuring the diffraction efficiency of a grating provided in the second embodiment of the present application. Detailed implementation manners

[0030] Many specific details are set forth in the following description in order to provide a thorough understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application. Therefore, the present application is not limited by the specific implementations disclosed below.

[0031] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The descriptive methods used in this application and the appended claims, such as "a", "first", and "second", etc., are not intended to limit the quantity or the order, but to distinguish the same type of information from each other.

[0032] An embodiment of this application provides a grating diffraction efficiency measurement system and method, which will be described in detail below in conjunction with the drawings of the embodiments provided in this application.

[0033] The first embodiment

[0034] Please refer to Figure 1 , which is a logical framework diagram of a grating diffraction efficiency measurement system provided by the first embodiment of this application. In Figure 1 , the grating diffraction efficiency measurement system includes a laser energy measurement device 100 and a grating diffraction efficiency analysis device 200.

[0035] Among them, when the laser beam is incident on the grating under test and the highly reflective flat mirror through the transmission of the semi-transmissive and semi-reflective coating lens and the beam splitter respectively, the laser energy measurement device 100 is used to record the first energy value E1 and the third energy value E3 of the first energy meter 203 respectively, and record the second energy value E2 and the fourth energy value E4 of the second energy meter 204 after the laser beam is reflected by the semi-transmissive and semi-reflective coating lens.

[0036] The grating diffraction efficiency analysis device 200 is used to calculate the grating diffraction efficiency of the grating under test. Specifically, according to the pre-determined energy conversion relationship (described in detail in the following point (2)), the second energy value E2 obtained by the second energy meter 204 is converted into a fifth energy value E5, and the fourth energy value E4 obtained by the second energy meter 204 is converted into a sixth energy value E6. The difference between the fifth energy value and the sixth energy value is obtained, and the third energy value E3 and this difference are added to obtain a seventh energy value E7; the ratio between the first energy value E1 and the seventh energy value E7 is used as the grating diffraction efficiency of the grating under test.

[0037] Here, when calculating the grating diffraction efficiency of the grating under test, the difference between the fifth energy value E5 and the sixth energy value E6 is used to determine the difference in the output energy between the laser beam incident on the grating under test and the laser beam incident on the highly reflective flat mirror, reducing the influence of the output energy difference between the two laser beams on the measurement accuracy of the grating diffraction efficiency, thereby improving the measurement accuracy of the grating diffraction efficiency.

[0038] The following is a specific analysis.

[0039] Please refer to Figure 2, which is a schematic diagram of the laser energy measurement device provided in the first embodiment of the present application for measuring the energy value of the diffracted beam of the grating to be measured. As Figure 2 shown, the laser light source can be the beam emitted by the laser 110, and the emitted beam of the laser light source is like the beam shown as 401 in Figure 2 . The beam splitting component is arranged in the optical path of the emitted beam of the laser light source and includes a semi-transmissive and semi-reflective coated lens 302 and a beam splitter 303. The emitted beam 401 of the laser light source is split into a transmitted beam and a reflected beam by the semi-transmissive and semi-reflective coated lens 302. The grating to be measured 202 is arranged in the first optical path 402 where the transmitted beam is located, and the highly reflective flat mirror 201 can be moved vertically into or out of the first optical path 402. The transmitted beam is transmitted through the beam splitter 303 to the grating to be measured 202, and the reflected beam is incident on the second energy meter 204.

[0040] Before the laser beam is incident on the grating to be measured, it is first necessary to perform optical path collimation processing on the grating to be measured to determine the absolute zero position of the grating to be measured. Then, the grating to be measured is rotated by a preset angle from the absolute zero position. The process of performing optical path collimation processing on the grating to be measured is described first below.

[0041] (1) Optical path collimation processing, which is used to determine the absolute zero position of the grating to be measured.

[0042] Please refer to Figure 4 , which is a schematic diagram of performing optical path collimation processing on the grating to be measured provided in the first embodiment of the present application.

[0043] The beam splitting component further includes an adjustable aperture 301, which is used to eliminate the influence of stray light of the laser and facilitate using the uniformly energized part of the laser output to test the energy value corresponding to the diffracted beam of the grating to be measured; the adjustable aperture 301 is also used to improve the accuracy of optical path collimation when performing optical path collimation processing on the grating to be measured.

[0044] The optical path collimation component is used to adjust the grating to be measured to the absolute zero position, specifically to perform preliminary optical path collimation processing on the grating to be measured; based on the obtained result of the preliminary optical path collimation processing, perform target optical path collimation processing on the grating to be measured; based on the obtained result of the target optical path collimation processing, determine the current position of the grating to be measured as the absolute zero position.

[0045] In Figure 4 , the optical path collimation component further includes an electric aperture 214 arranged between the semi-transmissive and semi-reflective coated lens 302 and the beam splitter 303; a fluorescence prism component arranged in the fourth optical path; a fluorescence mirror component arranged in the third optical path.

[0046] The fluorescence prism component includes a fluorescence prism 208, a first fluorescence cross plate 209, and a first observation window 210.

[0047] The fluoroscope assembly includes a fluoroscope 211, a second fluorescence cross plate 212, and a second observation window 213.

[0048] The optical path collimation process includes two steps. The first step is to perform a preliminary optical path collimation process on the grating to be measured, which is briefly called the initial adjustment of the optical path collimation. The second step is to perform a target optical path collimation process on the grating to be measured, which is briefly called the fine adjustment of the optical path collimation. The following is a description of each step respectively.

[0049] The first step is to perform the initial adjustment of the optical path collimation.

[0050] Move the first adjustment stage 205 in the vertical direction to move the high-reflection plane mirror 201 out of the first optical path 402.

[0051] The outgoing beam of the laser beam passes through the semi-transparent and semi-reflective coated lens 302 to obtain a transmitted beam, which reaches the beam splitter 303 through the electro-optical diaphragm 214. Adjust the position of the grating to be measured so that the transmitted beam after being split by the beam splitter 303 is vertically incident on the first position of the grooved area of the grating to be measured, such as Figure 4 the position pointed to by the first optical path 402 in Figure 4 the grating to be measured; the reflected beam after being split by the beam splitter 303 is reflected to the fluorescence prism 208, and then is reflected by the fluorescence prism 208 to the second position of the non-grooved area of the grating to be measured, such as

[0052] the position pointed to by the fifth optical path 406 in

[0053] The second step is to perform the fine adjustment of the optical path collimation.

[0054] Move the first energy meter 203 in the horizontal direction to move it out of the third optical path 404.

[0055] Continue to adjust the second adjustment stage 207 so that the beam reflected back from the second position of the non-grooved area of the grating to be measured passes through the fluorescence prism 208, is reflected by the beam splitter 303, and enters the fluoroscope 211 through the electro-optical diaphragm 214.

[0056] Obtain the position and shape of the laser spot on the second fluorescence cross plate 212 through the second observation window 213, and adjust the adjustment knob of the adjustment bracket of the grating to be measured until the laser spot is located at the center position of the second fluorescence cross plate 212 and the shape of the laser spot is a dot shape, then the fine adjustment of the optical path collimation is completed.

[0057] The above is the process of collimating the absolute zero position of the grating to be measured before measuring the grating diffraction efficiency of the grating to be measured. Based on the above preliminary optical path collimation processing and target optical path collimation processing of the grating to be measured, the accuracy of obtaining the absolute zero position of the grating to be measured is improved.

[0058] After the optical path collimation processing of the absolute zero position of the grating to be measured, adjust the aperture of the electric diaphragm 214 to the maximum aperture to avoid the laser beam in the first optical path 402 being blocked.

[0059] In addition, to measure the grating diffraction efficiency of the grating to be measured, the laser beam at the first moment is incident on the grating to be measured, and the energy value of the diffracted beam returned by the grating to be measured is obtained through the first energy meter 203; the laser beam at the second moment is incident on the high-reflection flat mirror, and the energy value of the reflected beam returned by the high-reflection flat mirror is obtained through the first energy meter 203. The ratio between the energy value of the diffracted beam returned by the grating to be measured and the energy value of the reflected beam returned by the high-reflection flat mirror is used as the grating diffraction efficiency. The influence of the difference between the output energy values of the laser beams at the two moments on the calculated grating diffraction efficiency is not considered in this process.

[0060] Among them, in order to avoid the difference between the output energy values of the laser beams at the two moments from affecting the measurement accuracy of the grating diffraction efficiency, the present application also adds a second energy meter 204 to respectively record the energy values of the laser beams at the two moments reflected to the second energy meter after being split by the semi-transmissive and semi-reflective coating lens 302, and fit the change of the measured output energy value of the laser.

[0061] (2) Fitting the change of the measured output energy value of the laser, that is, determining the energy conversion relationship for converting the energy value of the second energy meter into the energy value of the first energy meter.

[0062] The energy conversion relationship for converting the energy value of the second energy meter determined in advance into the energy value of the first energy meter is obtained through the following method:

[0063] Obtain multiple laser beams with known energy values, and the energy values of the multiple laser beams respectively present a preset change relationship. For each laser beam, perform the following operations: Incident the transmitted beam after splitting the laser beam on the high-reflection flat mirror, and the beam reflected by the high-reflection flat mirror is incident on the first energy meter to obtain the eighth energy value. Incident the reflected beam after splitting the laser beam on the second energy meter to obtain the ninth energy value; use the eighth energy value and the ninth energy value as an energy value group of the laser beam; obtain the energy value groups respectively corresponding to the multiple laser beams, and analyze and obtain the energy conversion relationship for converting the energy value of the second energy meter into the energy value of the first energy meter according to the obtained multiple energy value groups.

[0064] Please refer to Figure 7, which is a process diagram of the energy conversion relationship for determining the energy value of the second energy meter to be converted into the energy value of the first energy meter provided in the first embodiment of the present application.

[0065] The high-reflection plane mirror 201 is moved into the first optical path 402 .

[0066] The laser 110 outputs laser beams at different times according to a certain energy output rule, and the output energy values of the laser beams output at multiple different times present a preset change relationship. For example, the laser is set to output the laser beam in a constant energy change increasing manner, or the laser is set to output the laser beam according to other energy ratio relationships.

[0067] Multiple groups of energy values corresponding to different moments are obtained through the first energy meter 203 and the second energy meter 204 .

[0068] The first energy meter 203 measures the energy value of the laser beam after it passes through the semi-transparent and semi-reflective coated lens 302 and the beam splitter 303 of the beam splitter component and then enters the high-reflection plane mirror 201, is then reflected by the high-reflection plane mirror 201, is transmitted again through the beam splitter 303, and is reflected by the semi-transparent and semi-reflective coated lens 302, which is recorded as the eighth energy value Y.

[0069] The second energy meter 204 measures the energy value of the laser beam after it is reflected by the semi-transparent and semi-reflective coated lens 302 , which is recorded as the ninth energy value X.

[0070] The eighth energy value and the ninth energy value are taken as the energy value group corresponding to the laser light beam at one moment, and multiple energy value groups (X1, Y1), (X2, Y2), (X3, Y3), (X4, Y4), and (X5, Y5) are obtained.

[0071] Please refer to Figure 8 , which is a schematic diagram of a fitting function for representing the energy conversion relationship of converting the energy value of the second energy meter into the energy value of the first energy meter provided in the first embodiment of the present application.

[0072] exist Figure 8 In the above, the obtained energy value groups (X1, Y1), (X2, Y2), (X3, Y3), (X4, Y4), (X5, Y5) are linearly fitted according to Formula 1.

[0073] Y=kX+b (Formula 1)

[0074] Thus, the k value and the b value in Formula 1 can be obtained, thereby obtaining an energy conversion relationship for converting the energy value obtained by the second energy meter into the energy value obtained by the first energy meter.

[0075] The above is the process of predetermining the energy conversion relationship for converting the energy value of the second energy meter into the energy value of the first energy meter.

[0076] (3) Measure the grating diffraction efficiency of the grating under test.

[0077] First, describe the structural distribution relationship and functions of each component of the laser energy measurement device: The laser energy measurement device includes a laser light source, an adjustment component, a beam splitting component, and an optical path collimation component.

[0078] As Figure 2 shown, the laser light source is the laser beam emitted by the laser 110. The adjustment component includes a highly reflective flat mirror 201, the grating under test 202, a first energy meter 203, and a second energy meter 204. The beam splitting component is disposed in the optical path 401 of the outgoing beam of the laser light source for splitting the outgoing beam into a transmitted beam and a reflected beam. The grating under test 202 is disposed in the first optical path 402 where the transmitted beam is located. The highly reflective flat mirror 201 is disposed in the region between the beam splitting component and the grating under test 202. The highly reflective flat mirror 201 can be moved vertically into or out of the first optical path 402.

[0079] The second energy meter 204 is disposed in the second optical path 403 where the reflected beam is located. The first energy meter 203 is disposed in the third optical path 404. The third optical path 404 is the optical path where the beam that returns after the transmitted beam incident on the highly reflective flat mirror 201 or the grating under test 202 passes through the beam splitting component again after reflection.

[0080] The optical path collimation component is used to adjust the grating under test to the absolute zero position (as Figure 4 shown).

[0081] The adjustment component is used to rotate the grating under test from the absolute zero position by a preset angle (as Figure 2 shown). Based on the highly reflective flat mirror 201 moving out of the first optical path 402, the first laser beam is incident on the grating under test 202 through the transmitted beam after splitting. The diffracted beam returning through the grating under test 202 is incident on the first energy meter 203 to obtain the first energy value E1. The reflected beam after splitting of the first laser beam is incident on the second energy meter 204 to obtain the second energy value E2. Based on the highly reflective flat mirror 201 moving into the first optical path 402, the second laser beam is incident on the highly reflective flat mirror 201 through the transmitted beam after splitting. The reflected beam returning through the highly reflective flat mirror 201 is incident on the first energy meter 203 to obtain the third energy value E3. The reflected beam after splitting of the second laser beam is incident on the second energy meter 204 to obtain the fourth energy value E4.

[0082] The above is the structural distribution relationship of each component in the laser energy measurement device and the description of the functions of each component.

[0083] The following specifically describes the laser energy measurement device for measuring the diffraction beam energy process of the grating to be measured and the reflected beam energy process of the high-reflection plane mirror.

[0084] 1. Measure the energy values respectively obtained by the first energy meter 203 and the second energy meter 204 during the process of the laser beam incident on the grating to be measured.

[0085] Specifically, the laser energy measuring device records the first energy value E1 of the diffracted light beam returned by the grating to be measured and incident on the first energy meter 203 , and records the second energy value E2 of the first laser beam reflected by the second energy meter 204 .

[0086] The following combination Figure 2 The process of obtaining the first energy value E1 and the second energy value E2 is described in detail.

[0087] (1) Move the high-reflection plane mirror 201 out of the first optical path 402.

[0088] (2) The grating 202 to be measured is adjusted from the absolute zero position to a preset angle.

[0089] By adjusting the rotating stage 206 carrying the grating to be measured 202, the grating to be measured 202 is adjusted from the absolute zero position to a preset angle, and the following is obtained: Figure 2 The process of adjusting the grating to be measured from the absolute zero position to the preset angle can be referred to Figure 6 , which is a schematic diagram of rotating the grating to be measured from the absolute zero position to a preset angle provided by the first embodiment of the present application. Figure 6 In the embodiment, the grating to be measured is adjusted by a preset angle, that is, adjusted from the first direction to the second direction, wherein the preset angle at which the grating to be measured is adjusted is the grating blaze angle θ of the grating to be measured. B The structure diagram of the grating to be tested can be found in Figure 5 , which is a structural diagram of the grating to be measured provided by the first embodiment of the present application. Figure 5 501 in the figure represents the left view of the grating to be measured. Figure 5 502 in FIG. 5 represents the front view of the grating to be measured. Figure 5 From 501 in FIG. 1 , it can be seen that the blazing surface of the grooved area of the grating to be measured is the surface shown in 102, and the blazing angle is θ B .Depend on Figure 5 As can be seen from 502 , the surrounding area of the grating to be measured is the non-grooved area 101 , and the remaining part is the grooved area of the grating to be measured, which includes a plurality of groups of notched parts 103 and a blazing surface 102 .

[0090] (3) The grating to be measured is calibrated by adjusting the preset angle from the absolute zero position.

[0091] Move the first energy meter 203 horizontally out of the third optical path 404. After adjusting the grating under test to a preset angle, when the transmitted beam after splitting of the first laser beam is incident on the grating under test, the diffracted beam returned by the grating under test passes through the center of the electro - optical aperture 214, and is reflected to the center of the second fluorescence cross - plate after passing through the semi - transparent and semi - reflecting coating lens 302, indicating that the grating under test 202 is adjusted to the preset angle. At this time, the position of the grating under test is the target measurement position. Adjust the aperture of the electro - optical aperture 214 to the maximum aperture, and move the first energy meter 203 horizontally into the third optical path 404 to measure the energy value of the diffracted beam of the grating under test. As Figure 2 shown, the first energy meter 203 moves horizontally from the dotted area on the right to the solid area on the left, indicating that it moves into the third optical path 404.

[0092] (4) Measure the first energy value E1 obtained by the first energy meter 203 and the second energy value E2 obtained by the second energy meter.

[0093] At the target measurement position of the grating under test, after the first laser beam passes through the semi - transparent and semi - reflecting coating lens 302, the electro - optical aperture 214, and the beam splitter 303 for transmission, it is vertically incident on the blaze surface of the grooved area of the grating under test 202 to obtain the diffracted beam returned by the blaze surface of the grating under test 202. At this time, the diffracted beam of the blaze surface of the grating under test and the transmitted beam of the first laser beam coincide and are both in the first optical path 402. The diffracted beam passes through the transmission of the beam splitter 303 again, and then is reflected by the semi - transparent and semi - reflecting coating lens 302 and incident on the first energy meter 203 to obtain the first energy value E1 at this time.

[0094] While the first laser beam passes through the semi - transparent and semi - reflecting coating lens for transmission, there is also a part of the beam reflected by the semi - transparent and semi - reflecting coating lens and reaches the second energy meter to obtain the second energy value E2. Since the transmitted beam of the first laser beam and the diffracted beam of the grating under test coincide and there is no angle between them, there is no deviation between the transmitted beam of the first laser beam and the diffracted beam of the grating under test, and the loss difference of the energy value of the laser beam obtained by the first energy meter is reduced, thereby improving the measurement result of the grating diffraction efficiency of the grating under test.

[0095] The above process describes the process in which a laser beam is incident on a grating to be measured at a certain moment, and the first energy meter obtains the first energy value E1 and the second energy meter obtains the second energy value E2. Among them, the first laser beam can represent the laser beam at at least one moment incident on the grating to be measured. When the laser beams at multiple moments are respectively incident on the grating to be measured, the first energy value E1 can be the average value of the multiple energy values obtained by the first energy meter for the multiple laser beams according to the above process, or the value obtained by calculating the multiple energy values of the first energy meter in the above process in other ways, which is not specifically limited here. Correspondingly, the second energy value E2 can also be the average value of the multiple energy values obtained by the second energy meter for the multiple laser beams respectively according to the above process, or the value obtained by calculating the multiple energy values of the second energy meter in the above process in other ways, which is not specifically limited here.

[0096] 2. The energy values respectively obtained by the first energy meter and the second energy meter during the measurement of the laser beam incident on the high-reflection flat mirror.

[0097] Specifically, the laser energy measurement device is based on the second laser beam being transmitted and then incident on the high-reflection flat mirror 201, records the third energy value E3 of the reflected beam returned by the high-reflection flat mirror incident on the first energy meter, and records the fourth energy value E4 of the second laser beam reflected to the second energy meter.

[0098] The following combines Figure 3 Specifically describe the acquisition process of the third energy value E3 and the fourth energy value E4. Figure 3 It is a schematic diagram of the laser energy measurement device provided by the first embodiment of the present application for measuring the energy value of the reflected beam of the high-reflection flat mirror.

[0099] (1) Move the high-reflection flat mirror 201 into the first optical path 402.

[0100] (2) Perform optical path collimation processing on the high-reflection flat mirror 201.

[0101] Move the first energy meter 203 out of the third optical path 404, and move the high-reflection flat mirror 201 into the first optical path 402. Incident the transmitted beam after splitting the second laser beam on the high-reflection flat mirror 201, and the obtained reflected beam passes through the electric diaphragm 214 and is reflected by the semi-transparent and semi-reflective coating lens 302 and then reaches the center of the second fluorescence cross plate, indicating that the high-reflection flat mirror 201 has completed the optical path collimation processing. Adjust the aperture of the electric diaphragm 214 to the maximum aperture, and move the first energy meter 203 horizontally into the third optical path 404 to perform the measurement of the energy value of the reflected beam of the high-reflection flat mirror 201.

[0102] (3) Measure the third energy value E3 obtained by the first energy meter and the fourth energy value E4 obtained by the second energy meter.

[0103] After the second laser beam is transmitted through the semi-transmissive and semi-reflective coating lens 302, the electro-optical diaphragm 214, and the beam splitter 303, it is vertically incident on the surface of the highly reflective flat mirror 201 to obtain the reflected beam returned by the highly reflective flat mirror 201. At this time, the reflected beam of the highly reflective flat mirror and the transmitted beam of the second laser beam coincide and are both located in the first optical path 402. The reflected beam passing through the highly reflective flat mirror 201 is transmitted through the beam splitter 303 respectively, and then reflected by the semi-transmissive and semi-reflective coating lens 302 and incident on the first energy meter 203 to obtain the third energy value E3.

[0104] While the second laser beam is transmitted through the semi-transmissive and semi-reflective coating lens, there is also a part of the beam reflected by the semi-transmissive and semi-reflective coating lens and reaches the second energy meter to obtain the fourth energy value E4.

[0105] The above process describes the process in which the first energy meter obtains the third energy value E3 and the second energy meter obtains the fourth energy value E4 when the laser beam is incident on the highly reflective flat mirror at a certain moment. Among them, the second laser beam can be expressed as the laser beam at at least one moment incident on the highly reflective flat mirror. When the laser beams at multiple moments are respectively incident on the highly reflective flat mirror, the third energy value E3 can be the average value of the multiple energy values obtained by the multiple laser beams reaching the first energy meter according to the above process, or the value obtained by calculating the multiple energy values of the first energy meter in the process in other ways, and no specific limitation is made here. Correspondingly, the fourth energy value E4 can also be the average value of the multiple energy values obtained by the multiple laser beams respectively reaching the second energy meter according to the above process, or the value obtained by calculating the multiple energy values of the second energy meter in the process in other ways, and no specific limitation is made here.

[0106] Among them, there is no sequence requirement for the process of measuring the diffraction energy of the grating to be measured in the above point 1 and the process of measuring the reflection energy of the highly reflective flat mirror in point 2. The first process can be carried out first and then the second process, and vice versa.

[0107] 3. The grating diffraction efficiency analysis device analyzes and calculates the grating diffraction efficiency of the grating to be measured.

[0108] The grating diffraction efficiency analysis device is used to convert the energy value of the second energy meter into the energy value of the first energy meter according to the pre-determined energy conversion relationship, convert the second energy value obtained by the second energy meter into the fifth energy value, and convert the fourth energy value obtained by the second energy meter into the sixth energy value; obtain the grating diffraction efficiency of the grating to be measured according to the first energy value, the third energy value, the fifth energy value, and the sixth energy value.

[0109] Specifically, obtain the difference between the fifth energy value and the sixth energy value, and add the third energy value to the difference to obtain the seventh energy value; use the ratio between the first energy value and the seventh energy value as the grating diffraction efficiency of the grating to be measured.

[0110] The following is a specific description:

[0111] To improve the accuracy of calculating the grating diffraction efficiency of the grating to be measured, in this application, the output energy value of the laser is fitted through the above (2), and the energy conversion relationship for converting the energy value of the second energy meter to the energy value of the first energy meter is determined, that is, the k value and b value in Formula 1 are obtained.

[0112] According to Formula 1, X is E2, Y is E5, E5 = kE2 + b, and E5 is the energy value obtained by converting the second energy value E2 obtained by the second energy meter to the corresponding energy value of the first energy meter.

[0113] Correspondingly, X is E4, Y is E6, E6 = kE4 + b, and E6 is the energy value obtained by converting the fourth energy value E4 obtained by the second energy meter to the corresponding energy value of the first energy meter.

[0114] Obtain the difference between the fifth energy value E5 and the sixth energy value E6, add the third energy value E3 to the difference to obtain the seventh energy value E7; use the ratio between the first energy value E1 and the seventh energy value E7 as the grating diffraction efficiency of the grating to be measured.

[0115] Please refer to Formula 2:

[0116]

[0117] Among them, μ represents the grating diffraction efficiency;

[0118] E1 represents the first energy value of the diffracted beam after the transmitted beam corresponding to the first laser beam is incident on the grating to be measured;

[0119] E3 represents the third energy value of the reflected beam after the transmitted beam corresponding to the second laser beam is incident on the high-reflection plane mirror;

[0120] E5 represents the fifth energy value obtained by converting the second energy value of the reflected beam corresponding to the first laser beam incident on the second energy meter to the first energy meter;

[0121] E6 represents the sixth energy value obtained by converting the fourth energy value of the reflected beam corresponding to the second laser beam incident on the second energy meter to the first energy meter.

[0122] If the value of (E5 - E6) is 0, it indicates that the output energy values of the first laser beam and the second laser beam are the same. At this time, E7 = E3 + 0, that is, the third energy value E3 is equal to E7. Calculating the grating diffraction efficiency is to calculate the ratio of the first energy value E1 to the third energy value E3.

[0123] If the value of (E5 - E6) is not 0, it is discussed in two cases:

[0124] Case 1: The value of (E5 - E6) is greater than 0, indicating that the output energy value of the first laser beam is greater than that of the second laser beam. Therefore, in order to improve the measurement accuracy of calculating the grating diffraction efficiency, an energy difference is added to the third energy value E3 measured for the highly reflective flat mirror. At this time, the energy difference is positive, and the seventh energy value E7 is obtained. At this time, E7 is greater than E3. Then, the ratio of the first energy value E1 to the seventh energy value E7 is used as the grating diffraction efficiency.

[0125] Case 2: The value of (E5 - E6) is less than 0, indicating that the output energy value of the first laser beam is less than that of the second laser beam. Therefore, in order to improve the measurement accuracy of calculating the grating diffraction efficiency, an energy difference is added to the third energy value E3 measured for the highly reflective flat mirror. At this time, the energy difference is negative, and the seventh energy value is obtained. Here, E7 is less than E3. Then, the ratio of the first energy value E1 to the seventh energy value E7 is used as the grating diffraction efficiency.

[0126] The above is the detailed explanation of Formula 2. When the embodiment of the present application measures the grating diffraction efficiency of the grating to be measured, the absolute zero position of the grating to be measured is first determined, which initially improves the measurement accuracy of the grating diffraction efficiency. Then, in the process of calculating the grating diffraction efficiency based on the energy value corresponding to the diffracted beam of the grating to be measured and the energy value corresponding to the reflected beam of the highly reflective flat mirror, in order to avoid the difference between the energy value of the laser beam incident on the grating to be measured and the energy value of the laser beam incident on the highly reflective flat mirror, the energy values of the reflected beams corresponding to the two laser beams incident on the second energy meter are converted into the energy values corresponding to the first energy meter, and the energy difference between the two energy values is compared. Combining the energy difference with the third energy value reduces the influence of the energy value difference between the two laser beams on the measurement accuracy of the grating diffraction efficiency, thereby improving the measurement accuracy of calculating the grating diffraction efficiency.

[0127] Second Embodiment

[0128] Please refer to Figure 9 , which is a schematic flowchart of a method for measuring grating diffraction efficiency provided by the second embodiment of the present application. The method provided by the second instance of the present application is applied to a system for measuring grating diffraction efficiency provided by the first embodiment. For specific reference, please refer to the description of the system embodiment, which will not be elaborated here. The method includes steps S901 to S904.

[0129] As shown Figure 9 In step S901, a first laser beam is incident on a grating under test, and a first energy value of the diffracted beam returned by the grating under test and incident on a first energy meter is recorded, and a second energy value of the first laser beam reflected to a second energy meter is recorded.

[0130] This step is used to direct the first laser beam in the manner shown Figure 2 In the figure, through the transmission of a semi-transmissive and semi-reflective coating lens, an electro-optical diaphragm, and a beam splitter, it is vertically incident on the blaze surface of the grooved area of the grating under test, obtaining the diffracted beam returned by the blaze surface of the grating under test. After passing through the transmission of the beam splitter again and the reflection of the semi-transmissive and semi-reflective coating lens, it is incident on the first energy meter to obtain a first energy value E1. At the same time, while the first laser beam is transmitted through the semi-transmissive and semi-reflective coating lens, another part of the first laser beam is reflected by the semi-transmissive and semi-reflective coating lens and incident on the second energy meter to obtain a second energy value E2.

[0131] Among them, in the process of performing the above step S901 on the grating under test, the first laser beam is incident on the grating under test, which is specifically achieved in the following manner:

[0132] Move the highly reflective plane mirror out of the first optical path, rotate the grating under test by a preset angle from the absolute zero position, and the transmitted beam obtained by splitting the first laser beam by the beam splitting component is incident on the grating under test; among them, the beam splitting component is arranged in the optical path of the output beam of the laser beam and is used to split the output beam into a transmitted beam and a reflected beam; the grating under test is arranged in the first optical path where the transmitted beam is located, and the highly reflective plane mirror is arranged in the area between the optical path splitting component and the grating under test, and the highly reflective plane mirror can be moved vertically into or out of the first optical path.

[0133] Among them, when the highly reflective plane mirror is moved out of the first optical path and the grating under test is rotated by a preset angle to obtain the target measurement position of the grating under test, as Figure 2 shown in the figure, for specific details, reference can be made to the description in Part 1 of the process of measuring the grating diffraction efficiency of the grating under test in the first embodiment, which will not be elaborated here.

[0134] As Figure 9 shown in the figure, in step S902, a second laser beam is incident on the highly reflective plane mirror, and a third energy value of the reflected beam returned by the highly reflective plane mirror and incident on the first energy meter is recorded, and a fourth energy value of the second laser beam reflected to the second energy meter is recorded.

[0135] This step is used to direct the second laser beam in accordance with Figure 3In the manner shown, through the transmission of the semi-transmissive and semi-reflective coated lens, the electro-optical diaphragm, and the beam splitter, it is vertically incident on the plane of the highly reflective flat mirror to obtain the reflected beam of the highly reflective flat mirror. Then, it passes through the transmission of the beam splitter again and the reflection of the semi-transmissive and semi-reflective coated lens, and is incident on the first energy meter to obtain the third energy value E3. At the same time, while the second laser beam passes through the transmission of the semi-transmissive and semi-reflective coated lens, another part of the second laser beam is reflected by the semi-transmissive and semi-reflective coated lens and is incident on the second energy meter to obtain the fourth energy value E4.

[0136] Among them, in the process of performing the above step S902 on the highly reflective flat mirror, the second laser beam is incident on the highly reflective flat mirror, which is specifically realized in the following manner:

[0137] The highly reflective flat mirror is moved into the first optical path, and the transmitted beam obtained by splitting the second laser beam by the beam splitting assembly is incident on the highly reflective flat mirror.

[0138] Among them, the process of moving the highly reflective flat mirror into the first optical path, measuring the second laser beam incident on the highly reflective flat mirror, and obtaining the energy values of the first energy meter and the second energy meter can refer to the description in Part 2 of the process of measuring the grating diffraction efficiency of the grating to be measured in the first embodiment, which will not be elaborated here.

[0139] As Figure 9 shown, in step S903, according to the energy conversion relationship for converting the energy value of the second energy meter determined in advance into the energy value of the first energy meter, the second energy value obtained by the second energy meter is converted into the fifth energy value, and the fourth energy value obtained by the second energy meter is converted into the sixth energy value.

[0140] In this step, the energy conversion relationship for converting the energy value of the second energy meter determined in advance into the energy value of the first energy meter is obtained in the following manner:

[0141] Obtain multiple laser beams with known energy values, and the energy values of the multiple laser beams respectively present a preset change relationship. For each laser beam, perform the following operations: Make the transmitted beam after splitting the laser beam incident on the highly reflective flat mirror, and the beam reflected by the highly reflective flat mirror is incident on the first energy meter to obtain the eighth energy value. Make the reflected beam after splitting the laser beam incident on the second energy meter to obtain the ninth energy value; Take the eighth energy value and the ninth energy value as an energy value group of the laser beam; Obtain the energy value groups corresponding to the multiple laser beams respectively, and based on the obtained multiple energy value groups, analyze and obtain the energy conversion relationship for converting the energy value of the second energy meter into the energy value of the first energy meter.

[0142] The determination process of the above energy conversion relationship can refer to the specific description in part (2) of the first embodiment for fitting the measured output energy value of the laser, which will not be elaborated here.

[0143] The determination process of the above energy conversion relationship is the process of determining the k value and b value in formula 1 in the first embodiment. After determining the k value and b value in formula 1, according to formula 1, the second energy value E2 is converted into the fifth energy value E5, and the fourth energy value E4 is converted into the sixth energy value E6. Thus, the difference between the fifth energy value E5 and the sixth energy value E6 is considered to determine the difference between the output energy value of the laser beam incident on the grating under test and the output energy value of the laser beam incident on the high-reflection flat mirror, thereby improving the accuracy of calculating the grating diffraction efficiency of the grating under test.

[0144] As Figure 9 shown, in step S904, according to the first energy value, the third energy value, the fifth energy value, and the sixth energy value, the grating diffraction efficiency of the grating under test is obtained.

[0145] This step is used to calculate the grating diffraction efficiency of the grating under test. According to the first energy value, the third energy value, the fifth energy value, and the sixth energy value, the grating diffraction efficiency of the grating under test is obtained. Specifically, it can be achieved in the following way:

[0146] Obtain the difference between the fifth energy value and the sixth energy value, and perform an addition process on the third energy value and the difference to obtain the seventh energy value; take the ratio between the first energy value and the seventh energy value as the grating diffraction efficiency of the grating under test.

[0147] The process of the grating diffraction efficiency of the grating under test described above is obtained by calculating according to formula 2 in the first embodiment. When testing the grating diffraction efficiency of the grating under test in the embodiment of the present application, first, the grating under test is adjusted to a preset angle to ensure that the transmission beam corresponding to the laser beam is incident on the grating under test in the same direction as the diffraction beam of the grating under test for the transmission beam, thereby improving the data accuracy of obtaining the energy value of the diffraction beam (which can be called the diffraction energy value of the grating under test). Then, when calculating the grating diffraction efficiency according to the diffraction energy value of the grating under test and the reflection energy value corresponding to the reflected beam of the high-reflection flat mirror, in order to avoid the difference between the output energy value of the laser beam incident on the grating under test and the output energy value of the laser beam incident on the high-reflection flat mirror, the energy values of the reflected beams corresponding to the two laser beams incident on the second energy meter are converted into the energy values corresponding to the first energy meter, and the energy difference between the two energy values is compared. Combine the energy difference with the third energy value to reduce the influence of the energy value difference between the two laser beams on the measurement accuracy of the grating diffraction efficiency, thereby improving the accuracy of calculating the grating diffraction efficiency.

[0148] Although the present application is disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application shall be subject to the scope defined by the claims of the present application.

Claims

1. A grating diffraction efficiency measurement system, characterized in that, Comprising: A laser energy measurement device and a grating diffraction efficiency analysis device; the laser energy measurement device is used to record the first energy value of the diffracted beam generated by the grating under test for the first laser beam incident on the first energy meter, and record the second energy value of the first laser beam reflected to the second energy meter; record the third energy value of the reflected beam generated by the highly reflective flat mirror for the second laser beam incident on the first energy meter, and record the fourth energy value of the second laser beam reflected to the second energy meter; The grating diffraction efficiency analysis device is used to convert the second energy value obtained by the second energy meter into a fifth energy value and the fourth energy value obtained by the second energy meter into a sixth energy value according to the pre-determined energy conversion relationship for converting the energy value of the second energy meter into the energy value of the first energy meter; obtain the grating diffraction efficiency of the grating under test according to the first energy value, the third energy value, the fifth energy value and the sixth energy value.

2. The system according to claim 1, wherein The grating diffraction efficiency analysis device is used to obtain the difference between the fifth energy value and the sixth energy value, and perform an addition process on the third energy value and the difference to obtain a seventh energy value; use the ratio between the first energy value and the seventh energy value as the grating diffraction efficiency of the grating under test.

3. The system according to claim 1, wherein The laser energy measurement device includes a laser light source, an adjustment component, a beam splitting component, and an optical path collimation component; The adjustment component includes a highly reflective flat mirror, a grating under test, a first energy meter, and a second energy meter; The beam splitting component is arranged in the optical path of the output beam of the laser light source and is used to split the output beam into a transmitted beam and a reflected beam; the grating under test is arranged in the first optical path where the transmitted beam is located, the highly reflective flat mirror is arranged in the area between the beam splitting component and the grating under test, and the highly reflective flat mirror can be moved vertically into or out of the first optical path; The second energy meter is arranged in the second optical path where the reflected beam is located; the first energy meter is arranged in the third optical path, and the third optical path is the optical path where the beam returns after the transmitted beam incident on the highly reflective flat mirror or the grating under test passes through the beam splitting component again after reflection; The optical path collimation component is used to adjust the grating under test to the absolute zero position; the adjustment component is used to rotate the grating under test from the absolute zero position by a preset angle; based on the highly reflective flat mirror moving out of the first optical path, the first laser beam is incident on the grating under test through the transmitted beam after splitting, and the diffracted beam returning through the grating under test is incident on the first energy meter to obtain the first energy value, and the reflected beam after splitting of the first laser beam is incident on the second energy meter to obtain the second energy value; based on the highly reflective flat mirror moving into the first optical path, the second laser beam is incident on the highly reflective flat mirror through the transmitted beam after splitting, and the reflected beam returning through the highly reflective flat mirror is incident on the first energy meter to obtain the third energy value, and the reflected beam after splitting of the second laser beam is incident on the second energy meter to obtain the fourth energy value.

4. The system according to claim 1, wherein The energy conversion relationship for converting the energy value of the pre-determined second energy meter into the energy value of the first energy meter is obtained in the following manner: Obtain multiple laser beams with known energy values, where the energy values of the multiple laser beams respectively exhibit a preset variation relationship. For each laser beam, perform the following operations: Let the transmitted beam after splitting the laser beam be incident on the highly reflective flat mirror. The beam reflected by the highly reflective flat mirror is incident on the first energy meter to obtain an eighth energy value, and the reflected beam after splitting the laser beam is incident on the second energy meter to obtain a ninth energy value; Take the eighth energy value and the ninth energy value as an energy value group of the laser beam; Obtain the energy value groups corresponding to the multiple laser beams respectively. Based on the obtained multiple energy value groups, analyze and obtain the energy conversion relationship for converting the energy value of the second energy meter into the energy value of the first energy meter.

5. The system according to claim 3, characterized in that, The adjustment component is used to rotate the grating under test by a preset angle from the absolute zero position. Specifically, it adjusts the rotating table carrying the grating under test to rotate the grating under test by a preset angle from the absolute zero position, and the preset angle is the grating blazing angle of the grating under test.

6. The system according to claim 3, wherein The optical path collimation component is used to adjust the grating under test to the absolute zero position. Specifically, it performs a preliminary optical path collimation process on the grating under test; Based on the obtained preliminary optical path collimation processing result, perform a target optical path collimation process on the grating under test; Based on the obtained target optical path collimation processing result, determine the current position of the grating under test as the absolute zero position.

7. A method for measuring the diffraction efficiency of a grating, characterized in that, Comprising: The first laser beam is incident on the grating under test. Record the first energy value of the diffracted beam returned by the grating under test when it is incident on the first energy meter, and record the second energy value of the first laser beam when it is reflected to the second energy meter; The second laser beam is incident on the highly reflective flat mirror. Record the third energy value of the reflected beam returned by the highly reflective flat mirror when it is incident on the first energy meter, and record the fourth energy value of the second laser beam when it is reflected to the second energy meter; According to the energy conversion relationship for converting the energy value of the pre-determined second energy meter into the energy value of the first energy meter, convert the second energy value obtained by the second energy meter into a fifth energy value, and convert the fourth energy value obtained by the second energy meter into a sixth energy value; Based on the first energy value, the third energy value, the fifth energy value, and the sixth energy value, obtain the grating diffraction efficiency of the grating under test.

8. The method according to claim 7, characterized in that The obtaining of the grating diffraction efficiency of the grating under test based on the first energy value, the third energy value, the fifth energy value, and the sixth energy value includes: Obtain the difference between the fifth energy value and the sixth energy value, and perform an addition process on the third energy value and the difference to obtain a seventh energy value; Take the ratio between the first energy value and the seventh energy value as the grating diffraction efficiency of the grating under test.

9. The method according to claim 7, characterized in that The incidence of the first laser beam on the grating to be measured includes: moving the high-reflection plane mirror out of the first optical path, rotating the grating to be measured by a preset angle from the absolute zero position, and making the transmitted beam obtained after the first laser beam is split by the beam splitting component incident on the grating to be measured; The incidence of the second laser beam on the high-reflection plane mirror includes: moving the high-reflection plane mirror into the first optical path, and making the transmitted beam obtained after the second laser beam is split by the beam splitting component incident on the high-reflection plane mirror; Wherein, the first laser beam and the second laser beam are respectively laser beams at two different times emitted by a laser light source, the beam splitting component is arranged in the optical path of the emitted beam of the laser beam and is used for splitting the emitted beam into a transmitted beam and a reflected beam; the grating to be measured is arranged in the first optical path where the transmitted beam is located, the high-reflection plane mirror is arranged in the area between the optical path splitting component and the grating to be measured, and the high-reflection plane mirror can be moved into or out of the first optical path in the vertical direction.

10. The method according to claim 7, wherein The energy conversion relationship for converting the energy value of the pre-determined second energy meter into the energy value of the first energy meter is obtained through the following method: Obtain a plurality of laser beams with known energy values, and the energy values of the plurality of laser beams respectively present a preset change relationship. For each laser beam, perform the following operations: Make the transmitted beam after splitting the laser beam incident on the high-reflection plane mirror, and make the beam reflected by the high-reflection plane mirror incident on the first energy meter to obtain an eighth energy value. Make the reflected beam after splitting the laser beam incident on the second energy meter to obtain a ninth energy value; Take the eighth energy value and the ninth energy value as an energy value group of the laser beam; Obtain the energy value groups respectively corresponding to the plurality of laser beams, and based on the obtained plurality of energy value groups, analyze and obtain the energy conversion relationship for converting the energy value of the second energy meter into the energy value of the first energy meter.

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