Optimization method and system for measuring beam diameter of solid laser by adopting trepanning method

Abstract

The invention provides an optimization method and system for measuring the beam diameter of a solid laser through a trepanning method, and belongs to the technical field of applied optics. A trepanning method for measuring the beam diameter of a solid laser is optimized, a light splitting type attenuator is selected, a second energy meter (or a second power meter) is added, and fluctuation change of output energy (or power) of the measured laser is monitored; diaphragms of various specifications are used for measurement, and least square fitting is carried out on test data to obtain the beam diameter.

Description

Technical Field

[0001] The present invention belongs to the technical field of applied optics, and particularly relates to an optimized method and system for measuring the beam diameter of a solid-state laser by using the aperture method. Background Art

[0002] The beam diameter is a very important parameter of the output beam of a solid-state laser. The national standard of China, GB / T 15175-2012, "Measuring Methods for Main Parameters of Solid-State Lasers" and the national military standard, GJB 5441-2005, "Testing Methods for Solid-State Lasers" both specify the measuring method for the beam diameter, specifically the aperture method. As Figure 1 shown, it generally includes a laser to be measured 1, an attenuator 2, a diaphragm 3, and an energy meter (or power meter) 4. The beam emitted from the laser to be measured 1 is attenuated and sampled by the attenuator 2. A diaphragm 3 with an appropriate diameter is placed between the attenuator 2 and the energy meter (or power meter) 4, and the position of the diaphragm is repeatedly adjusted in the direction perpendicular to the optical axis to make the energy (or power) received by the energy meter (or power meter) 4 the largest. At this time, it is considered that the diaphragm is coaxial with the laser beam, and the laser energy Q' (or power P') at this time is recorded. Compared with the energy Q (or power P) without the diaphragm, the diaphragm transmittance is calculated as shown in Equation (1) or Equation (2):

[0003]

[0004] When the aperture of the diaphragm is changed and when T = 86.5%, the measured diaphragm diameter d' is the beam diameter d; when the diaphragm transmittance T is close to 86.5%, the beam diameter d is calculated using Equation (3):

[0005]

[0006] In practical applications, there are the following two problems:

[0007] Firstly, it is very difficult to have a transmittance T of exactly 86.5% when using a certain diaphragm. Generally, the diaphragm transmittance T close to 86.5% is used, and the beam diameter d is calculated using Equation (3). In this way, two factors will increase the measurement error: 1) In each light output test, the output energy (or power) of the laser to be measured 1 cannot be made exactly the same, that is, Q and Q' (or P and P') are obtained under different light output energies (or powers) of the laser to be measured 1, and there is an error in the calculation of the diaphragm transmittance T; 2) Equation (3) is calculated using the test results of a single diaphragm sample, and the sample is too small, and the measurement accuracy is very limited.

[0008] Second, the detection aperture of the energy meter (or power meter) 4 should be at least twice the diameter d of the beam to be measured, ensuring that more than 99.9% of the beam energy (or power) enters the energy meter (or power meter) 4, so that the obtained data is valid. The detection apertures of off-the-shelf energy meters (or power meters) on the current market are limited, generally not exceeding Φ50mm. When the diameter d of the beam to be measured is large, the test requirements may not be met. Summary of the Invention

[0009] The object of the present invention is to provide an optimized method and system for measuring the beam diameter of a solid-state laser using the nested-hole method, so as to overcome the influence of factors such as the fluctuation of the output light energy (or power) of the laser to be measured and the single sample quantity on the measurement error, solve the problem of limited detection aperture of the energy meter (or power meter), and be conducive to improving the measurement accuracy and accuracy of the beam diameter of the solid-state laser.

[0010] The first aspect of the present invention discloses an optimized method for measuring the beam diameter of a solid-state laser using the nested-hole method. The optimized method includes:

[0011] Step S1: Attenuate and split the laser beam through a spectroscopic attenuator to obtain a first split beam and a second split beam;

[0012] Step S2: Measure the energy Q of the first split beam without a diaphragm using a first energy meter, and measure the energy Q of the second split beam without a diaphragm using a second energy meter c ;

[0013] Step S3: Set a diaphragm at a preset position, measure the energy Q' of the first split beam after passing through the diaphragm using a first energy meter, and measure the energy Q of the second split beam when the diaphragm is set at the preset position c ';

[0014] Step S4: Obtain the measurement results of Step S2 and Step S3 through a processing unit, and then calculate the transmittance of the current diaphragm based on the measurement results. Then, record the through-hole diameter and transmittance of the current diaphragm as a data point. The formula for calculating the transmittance T of the diaphragm is:

[0015]

[0016] Step S5: Replace the through-hole diameter of the diaphragm, and repeat Step S3 and Step S4 until n data points are obtained. According to the relationship between the diaphragm transmittance and the diaphragm diameter, perform least-squares data fitting on the n data points to obtain the beam diameter d; n is greater than or equal to 5.

[0017] Optionally, in Step S1, the energy of the first split beam is less than or equal to the energy of the second split beam.

[0018] Optionally, in the step S1, when the first split beam is a reflected beam, the reflected beam on the front surface of the spectroscopic attenuator is selected as the first split beam.

[0019] Optionally, in the step S1, when the first split beam is a transmitted beam, the parallelism of the front and rear surfaces of the spectroscopic attenuator is ≤ 10 arcseconds.

[0020] The second aspect of the present invention discloses an optimized method for measuring the beam diameter of a solid-state laser using the nested-hole method. The optimized method includes:

[0021] Step S10: Attenuate and split the laser beam through a spectroscopic attenuator to obtain a first split beam and a second split beam;

[0022] Step S20: Measure the power P of the first split beam without a diaphragm using a first power meter, and measure the power P of the second split beam without a diaphragm using a second power meter c ;

[0023] Step S30: Set a diaphragm at a preset position, measure the power P' of the first split beam passing through the diaphragm using a first power meter, and measure the power P of the second split beam when the diaphragm is set at the preset position c ';

[0024] Step S40: The processing unit obtains the measurement results of Step S20 and Step S30, and then calculates the transmittance of the current diaphragm based on the measurement results. Then, record the through-hole diameter and transmittance of the current diaphragm as a data point. The formula for calculating the transmittance T of the diaphragm is:

[0025]

[0026] Step S50: Replace the through-hole diameter of the diaphragm, and repeat Step S30 and Step S40 until n data points are obtained. According to the relationship between the diaphragm transmittance and the diaphragm diameter, perform least-squares data fitting on the n data points to obtain the beam diameter d; n is greater than or equal to 5.

[0027] Optionally, in the step S10, the energy of the first split beam is less than or equal to the energy of the second split beam.

[0028] The third aspect of the present invention discloses a test system for measuring the beam diameter of a solid-state laser using the nested-hole method. The test system includes: a laser to be measured, a spectroscopic attenuator, n diaphragms with different through-hole diameters, a first energy meter, a second energy meter, and a processing unit; n is greater than or equal to 5;

[0029] The laser to be measured is used to emit a laser beam;

[0030] The spectroscopic attenuator is used to attenuate and split a laser beam to obtain a first split beam and a second split beam;

[0031] The first energy meter is used to measure the energy Q of the first split beam without a diaphragm, or the first energy meter is used to measure the energy Q' of the first split beam after passing through a diaphragm arranged at a preset position;

[0032] The second energy meter is used to measure the energy Q of the second split beam without a diaphragm c , or the second energy meter is used to measure the energy Q c ' of the second split beam when a diaphragm is arranged at the preset position;

[0033] The processing unit is connected to the first energy meter and the second energy meter;

[0034] After replacing diaphragms with different through-hole diameters and performing n tests, the processing unit obtains the measurement results of the first energy meter and the second energy meter in each test. The processing unit is used to calculate the measurement results of the first energy meter and the second energy meter in each test to obtain the transmittance of each diaphragm, and then obtain n data points; among them, each data point is (D i , T i ); among them, D i is the through-hole diameter of the i-th diaphragm; T i is the transmittance of the i-th diaphragm, i = 1, 2,..., n; the formula for calculating the transmittance T of the diaphragm is:

[0035]

[0036] The processing unit is further used to perform least-squares data fitting on the n data points according to the relationship between the diaphragm transmittance and the diaphragm diameter to obtain the beam diameter d.

[0037] Optionally, the test system further includes: a first focusing element and a second focusing element;

[0038] The first focusing element is arranged between the preset position of the diaphragm and the first energy meter and is used to focus the first split beam;

[0039] The second focusing element is arranged between the spectroscopic attenuator and the second energy meter and is used to focus the second split beam.

[0040] A fourth aspect of the present invention discloses a test system for measuring the beam diameter of a solid-state laser by the nested-hole method. The test system includes: a laser to be measured, a spectroscopic attenuator, n diaphragms with different through-hole diameters, a first power meter, a second power meter, and a processing unit; n is greater than or equal to 5;

[0041] The laser to be measured is used to emit a laser beam;

[0042] The spectroscopic attenuator is used to attenuate and split a laser beam to obtain a first split beam and a second split beam;

[0043] The first power meter is used to measure the power P of the first split beam without a diaphragm, or the first power meter is used to measure the power P' of the first split beam after passing through a diaphragm set at a preset position;

[0044] The second power meter is used to measure the power P of the second split beam without a diaphragm c , or the second power meter is used to measure the power P of the second split beam when a diaphragm is set at the preset position c ';

[0045] The processing unit is connected to the first power meter and the second power meter;

[0046] After replacing the diaphragms with different through-hole diameters and performing n tests, the processing unit obtains the measurement results of the first power meter and the second power meter in each test. The processing unit is used to calculate the measurement results of the first power meter and the second power meter in each test to obtain the transmittance of each diaphragm, and then obtain n data points; where each data point is (D i , T i ); where D i is the through-hole diameter of the i-th diaphragm; T i is the transmittance of the i-th diaphragm, i = 1, 2,..., n; the formula for calculating the transmittance T of the diaphragm is:

[0047]

[0048] The processing unit is also used to perform least-squares data fitting on the n data points according to the relationship between the diaphragm transmittance and the diaphragm diameter to obtain the beam diameter d.

[0049] Optionally, the test system further includes: a first converging element and a second converging element;

[0050] The first converging element is arranged between the preset position of the diaphragm and the first power meter for converging the first split beam;

[0051] The second converging element is arranged between the spectroscopic attenuator and the second power meter for converging the second split beam.

[0052] In summary, the solution proposed by the present invention has the following technical effects: The present invention optimizes the aperture method for measuring the beam diameter of a solid-state laser, selects a spectroscopic attenuator and adds a second energy meter (or second power meter) to monitor the fluctuation of the output energy (or power) of the laser under test; uses diaphragms of various specifications for measurement, and performs least-squares fitting on the test data to obtain the beam diameter; adds a first focusing element and a second focusing element to reduce the beam diameter injected into the first energy meter (or first power meter) and the second energy meter (or second power meter). Through the above optimization measures, the problems of the influence of factors such as the fluctuation of the output light energy (or power) of the laser under test and the single sample quantity on the measurement accuracy are solved, and the problem of the limited detection aperture of the energy meter (or power meter) is solved, which is beneficial to improving the measurement accuracy and accuracy of the beam diameter of the solid-state laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0054] Figure 1 FIG. is a test system diagram adopted by the aperture method for measuring the beam diameter specified in the existing national standards and national military standards;

[0055] Figure 2 FIG. is a test system diagram adopted by the optimized method for measuring the beam diameter by the aperture method in the embodiment of the present invention;

[0056] Figure 3 FIG. is a schematic flow diagram of an optimized method for measuring the beam diameter by the aperture method in an embodiment of the present invention;

[0057] Figure 4 FIG. is a schematic flow diagram of another optimized method for measuring the beam diameter by the aperture method in an embodiment of the present invention;

[0058] Figure 5 FIG. is a schematic diagram of the calculation example results of the experiment and fitting calculation in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0060] Figure 2 This is a test system adopted by the optimization method for measuring the beam diameter using the nested hole method provided by the present invention. Figure 2 It includes a laser 1 to be measured, a spectroscopic attenuator 20, a diaphragm 3, a first energy meter (or first power meter) 40, a second energy meter (or second power meter) 50, a first converging element 60 (if necessary), and a second converging element 70 (if necessary). The beam emitted from the laser 1 to be measured is split by the attenuator 2. The beam with higher energy (or power) is incident on the second energy meter (or second power meter) 50 to monitor the change in the output energy (or power) of the laser 1 to be measured; the beam with lower energy (or power) passes through the diaphragm 3 and is incident on the first energy meter (or first power meter) 40 to measure the beam energy (or power) passing through the diaphragm 3. When the detection apertures of the first energy meter (or first power meter) 40 and the second energy meter (or second power meter) 50 are less than twice the diameter d of the beam to be measured, the first converging element 60 and the second converging element 70 are respectively added in front of the first energy meter (or first power meter) 40 and the second energy meter (or second power meter) 50 to reduce the beam diameter and make it match the detection apertures of the first energy meter (or first power meter) 40 and the second energy meter (or second power meter) 50.

[0061] The attenuator 2 is selected as the spectroscopic attenuator 20, and the second energy meter (or second power meter) 50 is added. The spectroscopic attenuator 20 is a beam splitter. After one beam of laser is incident on the spectroscopic attenuator 20, a part of the laser passes through the spectroscopic attenuator 20, and a part of the laser is reflected by the spectroscopic attenuator 20, that is, the spectroscopic attenuator 20 divides the output beam of the laser 1 to be measured into two or more beams. One beam passes through the diaphragm 3 and is incident on the first energy meter (or first power meter) 40 to measure the beam energy (or power) passing through the diaphragm, and the other beam is incident on the second energy meter (or second power meter) 50 to monitor the change in the output energy (or power) of the laser 1 to be measured.

[0062] When the diaphragm is not added, the first energy meter (or first power meter) 40 measures the energy Q (or power P), and the second energy meter (or second power meter) 50 measures the energy Q c (or power P c) After adding the aperture 3, the first energy meter (or the first power meter) 40 measures the energy Q′ (or the power P′), and the second energy meter (or the second power meter) 50 measures the energy Q c ′ (or the power P c ′). Then the corrected aperture transmittance is shown in Equation (4) or Equation (5):

[0063]

[0064] By monitoring the change of the output energy (or power) of the laser 1 under test through the second energy meter (or the second power meter) 50, the calculation of the aperture transmittance T is corrected, and the problem that the fluctuation of the output light energy (or power) of the laser under test affects the measurement accuracy is solved.

[0065] Furthermore, select apertures of multiple specifications, and the aperture diameters are D1, D2, ……, D n , conduct tests using the above apertures, and obtain the corresponding aperture transmittances T1, T2, ……, T n respectively. Then, according to the relationship formula (6) between the diameter and the transmittance, use the n data points (D i , T i )(i = 1, 2, ……, n) obtained from the test to perform least squares data fitting to obtain the beam diameter d.

[0066]

[0067] By conducting tests using apertures of multiple specifications and performing data fitting on the test data to obtain the beam diameter, the problem that the single sample quantity affects the measurement accuracy is solved.

[0068] Furthermore, when the beam diameter d to be measured is large and the detection apertures of the first energy meter (or the first power meter) 40 and the second energy meter (or the second power meter) 50 are less than 2 times the beam diameter d to be measured, first converging elements 60 and second converging elements 70 are respectively added in front of the first energy meter (or the first power meter) 40 and the second energy meter (or the second power meter) 50, generally convex lenses or concave mirrors, to reduce the beam diameter to match the detection apertures of the first energy meter (or the first power meter) 40 and the second energy meter (or the second power meter) 50, and inject them into the first energy meter (or the first power meter) 40 and the second energy meter (or the second power meter) 50 for energy (or power) measurement.

[0069] Furthermore, the spectral attenuator 20 should be selected such that the beam energy (or power) is attenuated to a level acceptable to the aperture 3, avoiding excessive energy (or power) of the downstream beam blocked by the aperture 3, which may damage the aperture 3 or cause thermal deformation of the aperture 3, increasing the measurement error. To reduce the energy (or power) of the beam blocked by the aperture 3, generally, the beam with smaller energy (or power) in the reflected beam and transmitted beam of the spectral attenuator 20 is selected for the measurement of the aperture transmittance, and the beam with larger energy (or power) is used for energy (or power) monitoring.

[0070] Furthermore, when the reflected beam is selected for the measurement of the aperture transmittance, the reflected beam from the front surface of the spectral attenuator 20 should be selected to avoid the change in the diameter of the reflected beam from the rear surface affecting the measurement result; when the transmitted beam is selected for the measurement of the aperture transmittance, the parallelism of the front and rear surfaces of the spectral attenuator 20 should be ≤ 10 arcseconds to avoid the change in the diameter of the transmitted beam.

[0071] Furthermore, when the output beam of the laser 1 to be measured contains multiple spectral line components or a continuous spectrum, the transmittance difference of the spectral attenuator 20 at each spectral line position or interval should be ≤ 10%, ensuring the effectiveness of the beam attenuation sampling by the spectral attenuator 20.

[0072] Furthermore, for the selection of the diameter of the aperture 3, the beam diameter can be pre-estimated as d0. In the range of approximately [d0 / 5, d0*2], an aperture is selected at intervals of approximately d0 / 5 or d0 / 10. It is recommended that the number of apertures is not less than 5, and there should be apertures in both the >d0 and <d0 intervals. The interval can be reduced near d0 to densify the measurement points.

[0073] Furthermore, the outer diameter of the aperture should be large enough to be greater than the measurement aperture of the first energy meter (or first power meter) 40 and the light passing aperture of the first focusing element 60 to ensure the blocking of the beam.

[0074] Furthermore, for the selection of the first energy meter (or first power meter) 40 and the second energy meter (or second power meter) 50, their parameters need to match the corresponding beam. The range of measurement is generally 1.2 - 10 times the energy Q (or power P) of the corresponding beam, and the detection aperture is generally more than 2 times the diameter of the corresponding beam. If the first focusing element 60 and the second focusing element 70 are used, the detection apertures of the first energy meter (or first power meter) 40 and the second energy meter (or second power meter) 50 should be more than 2 times the diameter of the converged beam.

[0075] Further, the first energy meter (or the first power meter) 40 and the second energy meter (or the second power meter) 50 generally should not be placed at the focal positions of the first focusing element 60 and the second focusing element 70 to avoid damaging the first energy meter (or the first power meter) 40 and the second energy meter (or the second power meter) 50 due to excessive energy density (or power density). It is recommended to place them at the corresponding positions where the diameter of the converged beam is 1 / 2 to 1 / 3 of the detection aperture of the first energy meter (or the first power meter) 40 and the second energy meter (or the second power meter) 50.

[0076] Please refer to Figure 3 or Figure 4 , and the test process is as follows:

[0077] Step a), set up the test optical path according to the Figure 2 shown measurement system;

[0078] Step b), without adding the aperture 3, measure the beam energy Q (or power P) received by the first energy meter (or the first power meter) 40 and the beam energy Q c (or power P c ) received by the second energy meter (or the second power meter) 50 at this time;

[0079] Step c), add the aperture 3 with a diameter of D, repeatedly adjust the position of the aperture along the direction perpendicular to the optical axis to make the energy (or power) received by the first energy meter (or the first power meter) 40 the maximum. At this time, it is considered that the aperture 3 is coaxial with the laser beam;

[0080] Step d), conduct the test, measure the beam energy Q′ (or power P′) received by the first energy meter (or the first power meter) 40 and the beam energy Q c ′ (or power P c ′) received by the second energy meter (or the second power meter) 50 at this time, and calculate the corrected transmittance T corresponding to the aperture 3 with a diameter of D according to Equation (4) or Equation (5);

[0081] Step e), select n apertures 3 with aperture diameters of D i (i = 1, 2,..., n). Each time, select 1 aperture 3 and place it at the same position as the aperture 3 in Step c), and repeat Step d) to obtain the transmittance T i corresponding to the aperture 3 with a diameter of D i ;

[0082] Step f), according to the relationship formula (6) between the diameter and the transmittance, use the n data points (D i , T i )(i = 1, 2,..., n) obtained from the experiment to perform least - squares data fitting to obtain the beam diameter d.

[0083] It should be noted that the above steps b), c) and d) can be executed sequentially, or steps c) and d) can be executed first and then step b).

[0084] Figure 5 are the example results of experiments and fitting calculations using the present invention. The test optical path is as Figure 2 shown. The laser 1 to be measured outputs continuously, the output beam power is about 280 W, and the diameter is estimated to be between 90 mm and 100 mm. In the experiment, a beam splitter with a transmittance-to-reflectance ratio of 3:1 is selected as the beam splitting type attenuator 20 to split the output beam of the laser 1 to be measured. The proportion of the transmitted beam power is about 75%. After being focused by the converging element 70, it is incident on the second power meter 50 to monitor the change of the output power of the laser 1 to be measured; the proportion of the reflected beam power is about 25%. After passing through the aperture 3, it is focused by the first converging element 60 and incident on the first power meter 40 to measure the beam power passing through the aperture 3. The ranges of the first power meter 40 and the second power meter 50 are 200 W and 1000 W respectively.

[0085] The above experiments are carried out without an aperture and with apertures with diameters of 60 mm, 70 mm, 80 mm, 90 mm, 95 mm, 100 mm, 110 mm, 120 mm, 130 mm, and 140 mm respectively. Among them, one measurement point 95 mm is encrypted between 90 mm and 100 mm. The power values collected by the first power meter 40 and the second power meter 50 are shown in the following table. Based on this, the aperture transmittance is calculated as follows:

[0086] Table 1 Detection power and aperture transmittance

[0087]

[0088] According to Equation (6), the least squares data fitting is performed using Matlab, and the beam diameter d = 99.7 mm corresponding to a power proportion of 86.5% is obtained. As Figure 5 shown, where the abscissa is the aperture diameter, the ordinate is the aperture transmittance, the red cross points are the experimental data points, and the black line is the curve fitted according to the experimental data points. Thus, the beam diameter corresponding to a power proportion of 86.5% is Φ99.7 mm.

[0089] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An optimized method for measuring the beam diameter of a solid-state laser using the nested-hole method, characterized in that, The optimization method includes: Step S1: Attenuate and split the laser beam through a spectroscopic attenuator to obtain a first split beam and a second split beam. Step S2, measure the energy Q of the first split beam without the diaphragm through the first energy meter, and measure the energy Q of the second split beam without the diaphragm through the second energy meter c ; Step S3, set a diaphragm at a preset position, measure the energy Q′ of the first split beam after passing through the diaphragm with a first energy meter, and measure the energy Q of the second split beam when the diaphragm is set at the preset position with a second energy meter c ′; Step S4: Obtain the measurement results of Step S2 and Step S3 through a processing unit, and then calculate the transmittance of the current aperture based on the measurement results. Then, record the through-hole diameter and transmittance of the current aperture as a data point. The formula for calculating the transmittance T of the aperture is: Step S5: Replace the through-hole diameter of the aperture and repeat Step S3 and Step S4 until n data points are obtained. According to the relationship between the aperture transmittance and the aperture diameter, perform least-squares data fitting on the n data points to obtain the beam diameter d; n is greater than or equal to 5.

2. The method according to claim 1, characterized in that, In Step S1, the energy of the first split beam is less than or equal to the energy of the second split beam.

3. The method according to claim 1, wherein In Step S1, if the first split beam is a reflected beam, select the reflected beam from the front surface of the spectroscopic attenuator as the first split beam.

4. The method according to claim 1, characterized in that, In Step S1, if the first split beam is a transmitted beam, the parallelism of the front and rear surfaces of the spectroscopic attenuator ≤ 10 arcseconds.

5. An optimized method for measuring the beam diameter of a solid-state laser using the nested-hole method, characterized in that, The optimization method includes: Step S10: Attenuate and split the laser beam through a spectroscopic attenuator to obtain a first split beam and a second split beam. Step S20, measure the power P of the first split beam without a diaphragm using a first power meter, and measure the power P of the second split beam without a diaphragm using a second power meter c ; Step S30, set a diaphragm at a preset position, measure the power P′ of the first split beam passing through the diaphragm with a first power meter, and measure the power P of the second split beam when the diaphragm is set at the preset position with a second power meter c ′; Step S40: Obtain the measurement results of Step S20 and Step S30 through a processing unit, and then calculate the transmittance of the current aperture based on the measurement results. Then, record the through-hole diameter and transmittance of the current aperture as a data point. The formula for calculating the transmittance T of the aperture is: Step S50: Replace the through-hole diameter of the aperture and repeat Step S30 and Step S40 until n data points are obtained. According to the relationship between the aperture transmittance and the aperture diameter, perform least-squares data fitting on the n data points to obtain the beam diameter d; n is greater than or equal to 5.

6. The method according to claim 5, wherein In Step S10, the energy of the first split beam is less than or equal to the energy of the second split beam.

7. A test system for measuring the beam diameter of a solid-state laser using the nested-hole method, characterized in that, The test system includes: a laser under test, a spectroscopic attenuator, n apertures with different through-hole diameters, a first energy meter, a second energy meter, and a processing unit; n is greater than or equal to 5; The laser under test is used to emit a laser beam. The spectroscopic attenuator is used to attenuate and split the laser beam to obtain a first split beam and a second split beam. The first energy meter is used to measure the energy Q of the first split beam without an aperture, or the first energy meter is used to measure the energy Q' of the first split beam after passing through the aperture set at a preset position. The second energy meter is used to measure the energy Q of the second split beam without a diaphragm c , or the second energy meter is used to measure the energy Q of the second split beam when a diaphragm is set at a preset position c '; The processing unit is connected to the first energy meter and the second energy meter. After replacing the diaphragms with different through-hole diameters and conducting n tests, the processing unit obtains the measurement results of the first energy meter and the second energy meter in each test. The processing unit is used to calculate the measurement results of the first energy meter and the second energy meter in each test to obtain the transmittance of each diaphragm, and then obtain n data points; where each data point is (D i , T i ); where D i is the through-hole diameter of the i-th diaphragm; T i is the transmittance of the i-th diaphragm, i = 1, 2,..., n; the formula for calculating the transmittance T of the diaphragm is: The processing unit is also used to perform least-squares data fitting on the n data points according to the relationship between the aperture transmittance and the aperture diameter to obtain the beam diameter d.

8. The test system according to claim 7, wherein The test system further includes: a first focusing element and a second focusing element; The first focusing element is arranged between the preset position of the aperture and the first energy meter and is used to focus the first split beam. The second focusing element is arranged between the spectroscopic attenuator and the second energy meter and is used to focus the second split beam.

9. A test system for measuring the beam diameter of a solid-state laser by using the nested hole method, characterized in that, The test system includes: a laser under test, a spectroscopic attenuator, n apertures with different through-hole diameters, a first power meter, a second power meter, and a processing unit; n is greater than or equal to 5; The laser under test is used to emit a laser beam; The spectroscopic attenuator is used to attenuate and split the laser beam to obtain a first split beam and a second split beam; The first power meter is used to measure the power P of the first split beam without a diaphragm, or the first power meter is used to measure the power P' of the first split beam after passing through the diaphragm set at a preset position; The second power meter is used to measure the power P of the second split beam without a diaphragm c , or, the second power meter is used to measure the power P' of the second split beam when a diaphragm is set at a preset position c '; The processing unit is connected to the first power meter and the second power meter; After replacing the diaphragms with different through-hole diameters and performing n tests, the processing unit obtains the measurement results of the first power meter and the second power meter in each test. The processing unit is used to calculate the measurement results of the first power meter and the second power meter in each test to obtain the transmittance of each diaphragm, and then obtain n data points; where each data point is (D i , T i ); where D i is the through-hole diameter of the i-th diaphragm; T i is the transmittance of the i-th diaphragm, i = 1, 2,..., n; the formula for calculating the transmittance T of the diaphragm is: The processing unit is further used to perform least-squares data fitting on n data points according to the relationship between the diaphragm transmittance and the diaphragm diameter to obtain the beam diameter d.

10. The test system according to claim 9, characterized in that, The test system further includes: a first focusing element and a second focusing element; The first focusing element is arranged between the preset position of the diaphragm and the first power meter and is used to focus the first split beam; The second focusing element is arranged between the spectroscopic attenuator and the second power meter and is used to focus the second split beam.

Images