Calibration device and method for a laser spot analyzer

Abstract

The application provides a kind of calibration device and method of laser spot analyzer, it is related to instrument metrology field.The device includes: laser, beam expander, first lens, rotating ground glass, second lens, reflective spatial light modulator, 4f imaging system;Beam expander is used to expand the laser beam emitted by laser;First lens is used to converge optical beam to ground glass surface;Rotating ground glass is used to convert optical beam into partially coherent beam;Second lens is used to project partially coherent beam onto spatial light modulator;Spatial light modulator is used to modulate optical beam;4f imaging system is used to image optical beam at light source surface.This device uses spatial light modulator to shape optical beam, can output stable, adjustable beam width laser beam at the same position, this device reduces the input laser spatial coherence to obtain partially coherent beam, reduces the influence of environmental disturbance on measurement results, and can be used for high-precision calibration of laser spot analyzer.

Description

Technical Field

[0001] This invention relates to the field of instrumentation technology, specifically to a calibration device and method for a laser spot analyzer. Background Technology

[0002] As the laser industry chain becomes increasingly sophisticated, various industries are placing greater emphasis on quality control in the manufacturing of laser products. For laser products, beam width is undoubtedly a crucial parameter, affecting the beam divergence angle and beam propagation speed. 2 Important spatial parameters such as beam width factor are also important. Currently, beam width is mainly defined by 1 / n, circumferential power, second moment, and Gaussian beamwidth. The definition of second moment established by the ISO standard has reached a general consensus; in this standard, the X-axis beam width is defined as four times the standard deviation of the X-axis transverse intensity spatial distribution. Currently, beam width is mainly measured using a laser beam analyzer (BPA). Based on this definition, it is essential and important to conduct traceability work on beam width measurements.

[0003] Currently, beam width measurement traceability is mainly performed through comparison, which involves measuring the same laser beam using a master standard and the device being calibrated to obtain the indication error. This method has been widely accepted by most metrology and calibration institutions and companies. However, this comparison method has the following drawbacks: each laser can only provide one beam width calibration value at the same location, making it impossible for users to understand the linearity of the equipment. A common solution is to change the measurement position or add a focusing lens to the optical path to obtain different standard values ​​for calibration. However, when there are many devices being calibrated, or when users want to understand the indication error of the equipment measuring different beam widths, it is usually necessary to remeasure the standard value for each parameter, increasing the workload of calibration personnel. Furthermore, the instability of laser output and environmental disturbances can increase the uncertainty of beam width measurement results. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the prior art by providing a calibration device and method for a laser spot analyzer, thereby solving the calibration problem of the laser spot analyzer.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a calibration device for a laser spot analyzer, the device comprising a laser, a beam expander, a first lens, a rotating frosted glass, a second lens, a reflective spatial light modulator, and a 4f imaging system;

[0007] Lasers are used to emit laser beams;

[0008] Beam expanders are used to expand the laser beam emitted by a laser.

[0009] The first lens is used to focus the expanded laser beam onto the rotating frosted glass surface;

[0010] The rotating frosted glass is located at the front focal plane of the second lens. The rotating frosted glass is used to convert the incident laser beam into a partially coherent beam.

[0011] The second lens is used to convert the partially coherent beam transmitted from the rotating frosted glass into a plane wave and project it onto the reflective spatial light modulator.

[0012] A Gaussian grating pattern is loaded onto the reflective spatial light modulator. The width of the Gaussian grating pattern is determined by preset parameters. The reflective spatial light modulator is used to modulate the incident partially coherent beam and form a modulated partially coherent beam.

[0013] The 4f imaging system includes a beam splitter, a third lens, and a fourth lens. The 4f imaging system is used to image a modulated partially coherent beam onto the light source surface, which is located at the back focal plane of the fourth lens. The light source surface is used to set up a standard laser spot analyzer or a laser spot analyzer to be calibrated.

[0014] Optionally, the modulation band of the reflective spatial light modulator is from 400 nm to 700 nm.

[0015] Optionally, a first aperture is provided between the second lens and the beam splitter.

[0016] Optionally, a second aperture is provided between the third lens and the fourth lens, and the second aperture is located at the rear focal plane of the third lens and at the front focal plane of the fourth lens.

[0017] Optionally, a reflector is provided between the third lens and the second aperture.

[0018] Optionally, the distance between the first lens and the rotating frosted glass can be adjusted so that the coherence length of the partially coherent beam formed after transmission through the rotating frosted glass ranges from 2 mm to 4 mm.

[0019] In a second aspect, the present invention provides a calibration method for a laser spot analyzer, the method being applied to a calibration apparatus for a laser spot analyzer according to the first aspect, the method comprising:

[0020] Calibration steps: Place a standard laser beam analyzer at the light source surface. Use multiple different preset parameters to load Gaussian grating patterns of different widths onto the reflective spatial light modulator. Then, use the standard laser beam analyzer to determine the different beam widths corresponding to the light source surface, thus establishing the correspondence between the beam width and the preset parameters. Remove the standard laser beam analyzer. Calibration is generally performed once a year. The calibration frequency can be adjusted appropriately according to the usage frequency of the device. Quarterly checks can be performed to check whether the output value of the beam width corresponding to the preset parameters has deviated. If the deviation exceeds the set value, recalibration should be performed in time.

[0021] Calibration steps: Place the laser spot analyzer to be calibrated on the light source surface, switch between the multiple different preset parameters and select the preset parameter, obtain the standard value of the beam width corresponding to the selected preset parameter according to the correspondence, and complete the calibration of the laser spot analyzer to be calibrated.

[0022] Repeat the above calibration steps to complete the calibration of the next laser spot analyzer to be calibrated.

[0023] The beneficial effects of this invention include:

[0024] The calibration device for the laser spot analyzer provided by this invention includes a laser, a beam expander, a first lens, a rotating frosted glass, a second lens, a reflective spatial light modulator, and a 4f imaging system. The laser emits a laser beam; the beam expander expands the laser beam emitted by the laser; the first lens focuses the expanded laser beam onto the surface of the rotating frosted glass; the rotating frosted glass is located at the front focal plane of the second lens and converts the incident laser beam into a partially coherent beam; the second lens transmits the partially coherent beam from the rotating frosted glass. The beam is transformed into a plane wave and projected onto a reflective spatial light modulator. A Gaussian grating pattern is loaded onto the reflective spatial light modulator, the width of which is determined by preset parameters. The reflective spatial light modulator modulates the incident partially coherent beam, forming a modulated partially coherent beam. The 4f imaging system includes a beam splitter, a third lens, and a fourth lens. The 4f imaging system images the modulated partially coherent beam onto the light source surface, located at the back focal plane of the fourth lens. The light source surface is used to set up a standard laser spot analyzer or a laser spot analyzer to be calibrated. This device utilizes a spatial light modulator for beam shaping, enabling the output of a stable, beam-width-adjustable laser beam at the same location. It uses a direct measurement method rather than a comparison method to calibrate the laser spot analyzer under test. This device reduces the spatial coherence of the input laser beam to obtain a partially coherent beam. Utilizing the resistance of partially coherent beams to atmospheric turbulence and environmental disturbances, it reduces the impact of environmental disturbances on the measurement results by addressing the beam properties, enabling high-precision calibration of laser spot analyzers. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A schematic diagram of the calibration device for the laser spot analyzer provided in an embodiment of the present invention is shown;

[0027] Figures 2A to 2C This invention provides Gaussian grating patterns with different beam widths loaded on an SLM.

[0028] Figures 3A to 3C The calibration device provided in this embodiment of the invention shows the result obtained at the light source surface compared to... Figures 2A to 2C The light intensity simulation diagram corresponding to the Gaussian grating pattern;

[0029] Figure 4 The graph showing the relationship between beam transmission factor and coherence length is shown.

[0030] Figures 5A to 5C This invention provides a beam pattern generated by capturing a light source surface using a BPA image, as shown in an embodiment of the invention.

[0031] Figure 6A and Figure 6B The linear beam emitted by the laser of the calibration device provided in the embodiment of the present invention and the beam pattern generated by the light source surface using BPA are shown respectively.

[0032] Figure 7 A schematic flowchart of the calibration method for the laser spot analyzer provided in an embodiment of the present invention is shown. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] As the laser industry chain becomes increasingly sophisticated, various industries are placing greater emphasis on quality control in the manufacturing of laser products. For laser products, beam width is undoubtedly a crucial parameter, affecting the beam divergence angle and beam propagation speed. 2Important spatial parameters such as beam width factor are also important. Currently, beam width is mainly defined by 1 / n, circumferential power, second moment, and Gaussian beamwidth. The definition of second moment established by the ISO standard has reached a general consensus; in this standard, the X-axis beam width is defined as four times the standard deviation of the X-axis transverse intensity spatial distribution. Currently, beam width is mainly measured using a laser beam analyzer (BPA). Based on this definition, it is essential and important to conduct traceability work on beam width measurements.

[0035] Currently, beam width measurement traceability is mainly performed through comparison, which involves measuring the same laser beam using a master standard and the device being calibrated to obtain the indication error. This method has been widely accepted by most metrology and calibration institutions and companies. However, this comparison method has the following drawbacks: each laser can only provide one beam width calibration value at the same location, making it impossible for users to understand the linearity of the equipment. A common solution is to change the measurement position or add a focusing lens to the optical path to obtain different standard values ​​for calibration. However, when there are many devices being calibrated, or when users want to understand the indication error of the equipment measuring different beam widths, it is usually necessary to remeasure the standard value for each parameter, increasing the workload of calibration personnel. Furthermore, the instability of laser output and environmental disturbances can increase the uncertainty of beam width measurement results.

[0036] To meet the traceability requirements of the laser industry for beam width measurement devices and improve the laser beam width calibration capability, this application designs a calibration device and method based on a spatial light modulator (SLM) with adjustable laser beam width for beam quality analyzers or laser spot measurement instruments, addressing the need for calibration of different beam widths of lasers in the same wavelength band.

[0037] In a first aspect, the present invention provides a calibration device for a laser spot analyzer, such as... Figure 1As shown, the device includes a laser 100, a beam expander (BE) 101, a first lens 102, a rotating ground glass (RGGD) 103, a second lens 104, a reflective spatial light modulator (SLM) 105, and a 4f imaging system. The laser 100 emits a laser beam; the beam expander 101 expands the laser beam emitted by the laser 100; the first lens 102 focuses the expanded laser beam onto the surface of the rotating ground glass 103; the rotating ground glass 103 is located at the front focal plane of the second lens 104, and the rotating ground glass 103 converts the incident laser beam into a partially coherent beam; the second lens 104 focuses the laser beam from the rotating ground glass onto the surface of the rotating ground glass 103. The partially coherent beam transmitted through the frosted glass 103 is converted into a plane wave and projected onto the reflective spatial light modulator 105. A Gaussian grating pattern is loaded onto the reflective spatial light modulator 105, the width of which is determined by preset parameters. The reflective spatial light modulator 105 is used to modulate the incident partially coherent beam and form a modulated partially coherent beam. The 4f imaging system includes a beam splitter (BS) 106, a third lens 107, and a fourth lens 108. The 4f imaging system is used to image the modulated partially coherent beam onto the light source surface, which is located at the back focal plane of the fourth lens 108. A laser spot analyzer (BPA) 109 is set at the light source surface. The laser spot analyzer 109 can be a standard laser spot analyzer or a laser spot analyzer to be calibrated.

[0038] Specifically, the laser emitted by laser 100 passes through beam expander (BE) 101 and is focused by first lens 102 onto the surface of rotating frosted glass (RGGD) 103. After transmission through the rotating frosted glass 103, the laser beam is dispersed, and the resulting partially coherent beam passes through second lens 104, becoming a plane wave that is projected onto reflective spatial light modulator (SLM) 105. A Gaussian grating pattern is loaded onto the reflective spatial light modulator 105, the width of which is determined by preset parameters. For example, by changing the preset parameters, the SLM can be loaded with... Figures 2A to 2C The Gaussian grating patterns with different widths shown are as follows. Figures 2A to 2C The Gaussian envelope width ratio is 1:2:4. The beam modulated by the reflective spatial light modulator 105 reaches the light source surface after passing through a 4f imaging system consisting of a beam splitter (BS) 106, a third lens 107, and a fourth lens 108. For example, when a beam is loaded onto an SLM... Figures 2A to 2C In the case of Gaussian grating patterns of different widths shown, the BPA 109 at the light source surface can be measured as follows: Figures 3A to 3C Partially coherent Gaussian beams of different widths are shown. Figures 3A to 3C The theoretically calculated beam width ratio is 1:2:4. This beam retains the advantages of fully coherent lasers, such as high directionality and good monochromaticity, and can also reduce its speckle effect, making it suitable for use in imaging optical metrology.

[0039] The reflective spatial light modulator 105 is communicatively connected to the first computer terminal 110, through which preset parameters are set. The laser spot analyzer 109 is communicatively connected to the second computer terminal 111, through which the laser spot image and related data captured by the laser spot analyzer 109 are acquired.

[0040] Figure 1 In the figure, f2, f3 and f4 represent the focal lengths of the second lens 104, the third lens 107 and the fourth lens 108, respectively. Figure 1 The dashed line in the image represents the optical path of the laser beam.

[0041] Optionally, the modulation band of the reflective spatial light modulator 105 is from 400 nm to 700 nm.

[0042] Optionally, a first aperture 112 is provided between the second lens 104 and the beam splitter 106.

[0043] Optionally, a second aperture 113 is provided between the third lens 107 and the fourth lens 108, and the second aperture 113 is located at the rear focal plane of the third lens and at the front focal plane of the fourth lens 108. Optionally, a reflector 114 is provided between the third lens 107 and the second aperture 113 to facilitate the optical path setting.

[0044] Optionally, the distance l1 between the first lens 102 and the rotating frosted glass 103 can be adjusted so that the coherence length of the partially coherent beam formed after transmission through the rotating frosted glass 103 is in the range of 2 mm to 4 mm. Specifically, for example, the distance l1 can be changed by adjusting the position of the first lens 102 along the optical axis.

[0045] Spatial light modulators are generally classified into transmissive spatial light modulators and reflective spatial light modulators. Compared to transmissive spatial light modulators, reflective spatial light modulators offer more precise light wave modulation. Reflective spatial light modulators are further divided into reflective amplitude modulation spatial light modulators and reflective phase modulation spatial light modulators. Among them, reflective amplitude modulation spatial light modulators offer more direct and simple modulation, while reflective phase modulation spatial light modulators have a more complex modulation procedure and optical path. In this application, the reflective spatial light modulator 105 employs a reflective amplitude modulation spatial light modulator, which simplifies the beam modulation required for laser spot analyzer calibration. Through repeated experiments, it was found that the 4f imaging system used in conjunction with the reflective amplitude modulation spatial light modulator achieves the best imaging quality and high long-term system stability when the lens focal length is 14-16 cm.

[0046] In conventional calibration methods, each calibration requires separate measurements using a master standard and the device under test for the same laser beam. Frequent repositioning is cumbersome, and misalignment between the master standard and the device under test can affect measurement accuracy. However, this calibration device only requires the use of a standard laser spot analyzer during the initial acquisition of preset parameters for the reflective spatial light modulator. By measuring with the standard laser spot analyzer, multiple preset parameters are determined. Because this calibration device is stable (described in detail below), subsequent calibration processes no longer require the standard laser spot analyzer; instead, the preset parameters are directly input to output a standard beam, thus enabling direct calibration of the device under test.

[0047] This device uses a spatial light modulator for beam shaping, which can output a stable, beam-width-adjustable laser beam at the same position. This device reduces the spatial coherence of the input laser beam to obtain a partially coherent beam. By utilizing the characteristics of partially coherent beams to resist atmospheric turbulence and environmental disturbances, the influence of environmental disturbances on measurement results is reduced from the beam properties. It can be used for high-precision calibration of laser spot analyzers.

[0048] The theoretical basis for this calibration device is as follows:

[0049] In the spatiotemporal domain, the statistical properties of a partially coherent beam, neglecting polarization characteristics, are expressed by the mutual coherence function (MCF).

[0050] J0(r1,r2)= <E * (r1)E(r2)> (1)

[0051] Where E represents the electric field fluctuation in the direction perpendicular to the transmission axis, r1 and r2 are the transverse positions of the light source surface, and vector brackets denote ensemble averaging. The traditional correlation function for partially coherent beams is the Gauss-Schelle model (GSM) function, which has been studied in detail both theoretically and experimentally over the past few decades. The MCF of the GSM is expressed as...

[0052] J0(r1,r2)=G0A(r1,r2)μ(r1,r2) (2)

[0053] In the formula, G0 is a constant, and the last two terms, A(r1,r2) and μ(r1,r2), represent the intensity distribution and coherence distribution of the beam, respectively, and are expressed as follows:

[0054]

[0055]

[0056] In the formula, σ0 represents the beam width of the generated GSM, and δ0 represents the coherence length of the beam. Equation 4 gives the coherence distribution of the light source surface, which is the Fourier transform of the light intensity distribution on the frosted glass.

[0057] In many practical applications, the beam propagation factor (also known as M) 2 The beam quality factor (M) is an important characteristic of a beam, considered as a beam quality factor. In free space, the M of a GSM beam... 2 Factors are represented as

[0058]

[0059] For a laser beam, if it is considered to be completely coherent, then δ0 = ∞, that is, M 2 =1 represents the transmission factor of an optimal, perfectly coherent Gaussian beam. However, in reality, since the coherence length of the laser output cannot be infinitely large, the M-value of the coherent laser beam... 2 The factor is always greater than 1. Figure 4 The relationship between the beam transmission factor and the coherence length (σ0 = 1 mm) is given. It is easy to see that over a long period of time when the coherence length gradually decreases, the beam quality factor of a partially coherent GSM beam will not increase much. This indicates that a partially coherent GSM beam retains the characteristics of a fully coherent laser.

[0060] Using a laser spot analyzer (model: BGS-USB3-LT665, manufacturer: Spiricon) traced back to the National Institute of Metrology of China, the measurement result uncertainty U rel =3%, k=2), the adjustability, short-term instability, long-term instability, and beam shaping capability of the device were monitored, and the results were obtained in Tables 1 to 3 and Figures 5 to 6 (the laser used on the calibration device and the reference laser are the same laser). X and Y represent the transverse and longitudinal beam widths of the Gaussian grating loaded on the SLM; x and y represent the transverse and longitudinal beam widths of the beam generated by the device as measured by BPA; instability η Represented as

[0061]

[0062] In the formula d max d represents the maximum measured beam width within the monitoring period. min This indicates the minimum beam width measurement within the monitoring period. This represents the average beam width measurement over the monitoring period.

[0063] Table 1 shows the calibration data for this calibration device, illustrating the adjustability of the laser beam width adjustment mechanism. The width of the Gaussian grating loaded onto the SLM can be adjusted by changing the width parameter in the control program. This calibration device can generate a Gaussian beam of the corresponding width at the light source surface (as shown in Figure 5, laser beam wavelength 633nm). Figures 5A to 5CThe beam width ratio shown is 1:2:4. Tables 2 and 3 compare the short-term and long-term instabilities of the laser beam width adjustment device and the reference laser source, respectively. When the reference laser is used as the source for this calibration device, both short-term and long-term instabilities are reduced by more than 3%. Figure 6A and Figure 6B This demonstrates the device's beam shaping capability, referencing the linear beam input from the laser. Figure 6A After passing through the device, a circular beam of light was output. Figure 6B Table 4 provides the traceability information for this calibration device.

[0064] Table 1. Adjustability of the device (unit: mm)

[0065]

[0066] Table 2 Short-term instabilities of calibration device and reference laser

[0067]

[0068] Table 3. Long-term instability of the device and reference laser over 6 hours

[0069]

[0070] Table 4. Traceability Table of Laser Beam Width Adjustment Device

[0071]

[0072]

[0073] The experimental results show that the calibration device is continuously adjustable within a width range of 0.1 mm to 5.0 mm. Utilizing the strong resistance to environmental disturbances inherent in partially coherent beams, the device exhibits short-term and long-term stability reductions of over 3% compared to the reference laser. Furthermore, based on the superior beam shaping capability of the SLM, the calibration device can output a Gaussian beam from an input irregular beam.

[0074] Secondly, the present invention provides a calibration method for a laser spot analyzer, which is applied to a calibration device for a laser spot analyzer as described in the first aspect above, such as... Figure 7 As shown, the method includes:

[0075] Step 701: Place the standard laser spot analyzer at the light source surface. Use multiple different preset parameters to load Gaussian grating patterns of different widths onto the reflective spatial light modulator. Then, use the standard laser spot analyzer to determine the different beam widths corresponding to the light source surface, thereby establishing the correspondence between the beam width and the preset parameters. Remove the standard laser spot analyzer. Step 701 is the calibration step. The calibration step is generally performed once a year. The calibration frequency can be adjusted appropriately according to the frequency of device use. It can also be checked quarterly to check whether the output value of the beam width corresponding to the preset parameters has deviated. If the deviation is found to exceed the set value, recalibrate in time.

[0076] Step 702: Place the laser spot analyzer to be calibrated at the light source surface, switch between and select the preset parameters from the multiple different preset parameters, and complete the calibration of the laser spot analyzer to be calibrated according to the correspondence between the beam width and the preset parameters. Step 702 is the calibration step. By repeating the above calibration steps, the calibration of the next laser spot analyzer to be calibrated is completed.

[0077] In summary, this application constructs a laser spot analyzer calibration device and method based on a spatial light modulator. This calibration device features adjustable output beam width, and the generated partially coherent laser beam does not suffer beam quality loss due to reduced spatial coherence, exhibiting better output stability and excellent resistance to environmental disturbances. Due to its powerful beam shaping capability, this calibration device is suitable for most 400nm–700nm milliwatt-level laser sources. The device has a complete traceability chain and can be used for high-precision calibration of laser spot analyzers. The output standard beam width of this calibration device is adjustable. During calibration, the device being calibrated is placed at the calibration location (i.e., at the light source surface) without needing to move; different beam widths can be calibrated by switching preset parameters on the reflective spatial light modulator.

[0078] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A calibration device for a laser spot analyzer, characterized in that, The device includes a laser, a beam expander, a first lens, a rotating frosted glass, a second lens, a reflective spatial light modulator, and a 4f imaging system. The laser is used to emit a laser beam; The beam expander is used to expand the laser beam emitted by the laser. The first lens is used to focus the expanded laser beam onto the rotating frosted glass surface; The rotating frosted glass is located at the front focal plane of the second lens, and the rotating frosted glass is used to convert the incident laser beam into a partially coherent beam. The second lens is used to convert a partially coherent beam transmitted from the rotating frosted glass into a plane wave and project it onto the reflective spatial light modulator. The reflective spatial light modulator is loaded with a Gaussian grating pattern, the width of which is determined by a preset parameter. The reflective spatial light modulator is used to modulate the incident partial coherent beam and form a modulated partial coherent beam. The 4f imaging system includes a beam splitter, a third lens, and a fourth lens. The 4f imaging system is used to image a modulated partially coherent beam onto a light source surface. The light source surface is located at the back focal plane of the fourth lens. The light source surface is used to set up a standard laser spot analyzer or a laser spot analyzer to be calibrated.

2. The calibration device for the laser spot analyzer according to claim 1, characterized in that, The modulation band of the reflective spatial light modulator is 400nm to 700nm.

3. The calibration device for the laser spot analyzer according to claim 1, characterized in that, A first aperture is provided between the second lens and the beam splitter.

4. The calibration device for the laser spot analyzer according to claim 3, characterized in that, A second aperture is provided between the third lens and the fourth lens, and the second aperture is located at the rear focal plane of the third lens and at the front focal plane of the fourth lens.

5. The calibration device for the laser spot analyzer according to claim 4, characterized in that, A reflector is provided between the third lens and the second aperture.

6. The calibration device for the laser spot analyzer according to claim 1, characterized in that, The distance between the first lens and the rotating frosted glass is adjustable so that the coherence length of the partially coherent beam formed after transmission through the rotating frosted glass ranges from 2 mm to 4 mm.

7. A calibration method for a laser spot analyzer, characterized in that, The method is applied to the calibration apparatus of a laser spot analyzer according to any one of claims 1 to 6, and the method comprises: A standard laser spot analyzer is placed at the light source surface, and multiple different preset parameters are used to load Gaussian grating patterns with different widths onto the reflective spatial light modulator. Then, the standard laser spot analyzer is used to determine the different beam widths corresponding to the light source surface, thereby establishing the correspondence between the beam width and the preset parameters. The standard laser spot analyzer is then removed. Place the laser spot analyzer to be calibrated on the light source surface, switch between and select preset parameters from multiple different preset parameters, obtain the standard value of the beam width corresponding to the selected preset parameter according to the correspondence, and complete the calibration of the laser spot analyzer to be calibrated.

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