Large-aperture nanosecond pulse laser flux high spatial resolution measurement method and system, electronic equipment and storage medium

Abstract

The invention relates to the technical field of laser flux measurement, in particular to a high-spatial-resolution measurement method and system for large-aperture nanosecond pulse laser flux, electronic equipment and a storage medium, and the method comprises the following steps: obtaining optical characteristic parameter spatial distribution of an original radiation developing film and light-proof paper; placing the radiation color developing film in a light path, and sequentially performing single irradiation on different positions of the radiation color developing film by using a plurality of groups of light beams with different laser fluxes; preprocessing the radiated radiation color developing film and extracting optical characteristic parameter spatial distribution of the preprocessed radiation color developing film; extracting net light density distribution before and after irradiation according to optical characteristic parameter spatial distribution of the original radiation color developing film, the light-proof paper and the preprocessed radiation color developing film; and fitting a relation curve of the laser flux and net light density distribution based on the net light density before and after irradiation. The objective of the invention is to realize accurate measurement of high-spatial-resolution large-aperture laser flux and reduce the measurement cost.

Description

Technical Field

[0001] The present invention relates to the technical field of laser flux measurement, and in particular to a high spatial resolution measurement method, system, electronic equipment and storage medium for large-aperture nanosecond pulse laser flux. Background Art

[0002] Laser technology is widely used in modern industry, medicine and daily life. In the field of high-power lasers and large-aperture laser devices, accurate measurement of beam quality is critical for system performance evaluation and optimization, and the flux distribution evaluation of the beam cross-section spot is the core element of measuring beam quality.

[0003] At present, the commonly used measurement methods in the existing technology are oscilloscope recording paper and beam quality analyzers based on scientific cameras; among them, oscilloscope recording paper is often used for preliminary evaluation of beam quality in small optical experiments due to its low cost and easy operation, but due to its inherent material properties and coloring mechanism, it is difficult to provide stable and high-precision flux distribution information, especially the insufficient ability to capture fine structures. On the other hand, although the beam quality analyzer can provide finer spatial resolution, its low laser-induced damage threshold and high cost limit its application in strong laser scenes and large-aperture laser devices; if the beam quality analyzer is deployed in a large laser system, not only is the equipment cost too high, but if it is placed in a complex optical path for low-energy, small-size spot processing and then detected, the reliability and accuracy of the information obtained will be reduced due to factors such as energy loss and spot distortion during the optical path conversion process, thus failing to meet the needs of strong lasers and large-aperture laser devices for accurate measurement of beam quality. Summary of the invention

[0004] The purpose of the present invention is to achieve accurate measurement of large-aperture laser flux with high spatial resolution and reduce measurement costs, and provide a high-spatial-resolution measurement method, system, electronic device and storage medium for large-aperture nanosecond pulse laser flux. The technical solutions adopted are as follows:

[0005] The technical solution of the first aspect of the present invention provides a high spatial resolution measurement method for large-aperture nanosecond pulse laser flux, the method comprising:

[0006] Obtaining the spatial distribution of optical characteristic parameters of the original radiochromic film and opaque paper;

[0007] The radiochromic film is placed in the optical path, and different positions of the radiochromic film are irradiated sequentially by using multiple groups of laser beams with different fluxes;

[0008] Preprocessing the irradiated radiochromic film and extracting the spatial distribution of optical characteristic parameters of the preprocessed radiochromic film;

[0009] Extract the net optical density distribution before and after irradiation based on the spatial distribution of optical characteristic parameters of the original radiochromic film, opaque paper and pre-treated radiochromic film;

[0010] The relationship curve between laser flux and net optical density distribution was fitted based on the net optical density before and after irradiation.

[0011] Furthermore, obtaining the spatial distribution of optical characteristic parameters of the original radiochromic film and the opaque paper includes:

[0012] Obtaining the brightness information and two-dimensional distribution of optical density values ​​of the original radiochromic film;

[0013] Obtain the two-dimensional distribution of brightness information of opaque paper.

[0014] Further, placing the radiochromic film in the optical path, and sequentially irradiating different positions of the radiochromic film with a plurality of groups of different laser flux beams include:

[0015] Place the radiochromic film in the optical path and calibrate the laser spot to be measured;

[0016] A single irradiation operation is performed on the radiochromic film in sequence based on a preset interval and using a plurality of groups of different laser flux beam pairs.

[0017] Further, preprocessing the irradiated radiochromic film and extracting the spatial distribution of optical characteristic parameters of the preprocessed radiochromic film includes:

[0018] The irradiated radiochromic film is stored and processed according to preset conditions;

[0019] Extract and save the brightness information and two-dimensional distribution of optical density values ​​of the processed radiochromic film.

[0020] Furthermore, the net optical density distribution before and after irradiation is extracted according to the spatial distribution of the optical characteristic parameters of the original radiochromic film, the opaque paper and the pre-treated radiochromic film, including:

[0021] The net optical density value was calculated using the average background fog subtraction method according to the relevant parameters of the target laser flux under different irradiation conditions.

[0022] Furthermore, the expression of the net optical density value is:

[0023]

[0024] In the formula, netOD represents the net optical density; OD exposed It indicates the optical density value of the radiochromic film after pretreatment; The average optical density of the original radiochromic film; PV exposedRGB values ​​of radiochromic film after preprocessing; Represents the mean RGB value of the original radiochromic film; Indicates the average RGB value of opaque paper.

[0025] The technical solution of the second aspect of the present invention provides a high spatial resolution measurement system for a large-aperture nanosecond pulse laser flux, using the high spatial resolution measurement method for a large-aperture nanosecond pulse laser flux described in the technical solution of the first aspect of the present invention, and the system comprises:

[0026] A first optical characteristic parameter acquisition module is used to acquire the spatial distribution of the optical characteristic parameters of the original radiochromic film and the opaque paper;

[0027] An irradiation device, used to sequentially irradiate different positions of the radiochromic film with a plurality of different laser fluxes;

[0028] A second optical characteristic parameter acquisition module is used to extract the spatial distribution of the optical characteristic parameters of the pre-processed radiochromic film;

[0029] A net optical density distribution extraction module is used to extract the net optical density distribution before and after irradiation according to the spatial distribution of optical characteristic parameters of the original radiochromic film and the radiochromic film after pretreatment;

[0030] A curve fitting module, used to fit the relationship curve between laser flux and net light density distribution based on the net light density before and after irradiation;

[0031] The laser flux acquisition module is used to determine the flux distribution of the laser to be measured based on the relationship curve between the laser flux and the net light density distribution.

[0032] Furthermore, the irradiation device includes a laser and a radiation chromogenic film, wherein the laser is arranged at intervals on one side of the radiation chromogenic film, and the laser is configured to perform a single irradiation operation on the radiation chromogenic film in sequence based on a preset interval and using multiple groups of different laser fluxes.

[0033] The technical solution of the second aspect of the present invention provides an electronic device, comprising: a processor and a memory communicatively connected to the processor; wherein the memory stores instructions executable by the processor, and the instructions are executed by the processor so that the processor can execute the steps of the high spatial resolution measurement method of large-aperture nanosecond pulse laser flux described in the technical solution of the first aspect of the present invention.

[0034] The technical solution of the second aspect of the present invention provides a computer-readable storage medium, on which is stored a program for implementing a high spatial resolution measurement method for a large-aperture nanosecond pulse laser flux. The program for implementing a high spatial resolution measurement method for a large-aperture nanosecond pulse laser flux is executed by a processor to implement the steps of the high spatial resolution measurement method for a large-aperture nanosecond pulse laser flux described in the technical solution of the first aspect of the present invention.

[0035] The present invention has the following beneficial effects:

[0036] The high spatial resolution measurement method of large-aperture nanosecond pulse laser flux provided by the present invention obtains the spatial distribution of optical characteristic parameters of the original radiation chromogenic film and opaque paper as a reference, and uses multiple groups of different laser flux beams to irradiate the radiation chromogenic film during the irradiation process, so that the method has a high spatial resolution at the micron level and can accurately locate the distribution of laser flux in a small area; at the same time, the high laser damage threshold of the radiation chromogenic film at the Joule level ensures the reliability when measuring high-energy laser flux, and will not damage the measurement equipment or affect the measurement results due to excessive laser energy. On the other hand, this method has no size restrictions on large-aperture spot measurement, and can be widely used in flux measurement tasks of various large-aperture laser systems, providing an efficient, accurate and reliable measurement method for the research and application of large-aperture and high-energy lasers in the field of laser flux measurement technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 A method flow chart of a method for measuring a large-aperture nanosecond pulse laser flux with high spatial resolution provided by one embodiment of the present invention;

[0039] Figure 2 A schematic diagram of the structure of a high spatial resolution measurement system for large-aperture nanosecond pulse laser flux provided by one embodiment of the present invention;

[0040] Figure 3 A schematic diagram of an optical path for measuring laser flux distribution provided by an embodiment of the present invention;

[0041] Figure 4 A schematic diagram of a curve showing the relationship between NetOD and laser flux at 355 nm provided by an embodiment of the present invention;

[0042] Figure 5 A schematic diagram of a curve showing the relationship between NetOD and laser flux at 532 nm provided by an embodiment of the present invention;

[0043] Figure 6 A schematic diagram of an absorption curve of an original RCF scanned by a spectrophotometer provided by an embodiment of the present invention;

[0044] Icon: 100-Laser, 200-Radiochromic Film. DETAILED DESCRIPTION

[0045] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the high spatial resolution measurement method, system, electronic device and storage medium of a large-aperture nanosecond pulse laser flux proposed by the present invention, its specific implementation, structure, features and effects in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0046] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0047] The following is a detailed description of a high spatial resolution measurement method, system, electronic device and storage medium for large-aperture nanosecond pulse laser flux provided by the present invention in conjunction with the accompanying drawings.

[0048] See also Figure 1 , which shows a method flow chart of a method for measuring a large-aperture nanosecond pulse laser flux with high spatial resolution provided by an embodiment of the present invention, the method comprising:

[0049] Step S100: obtaining the spatial distribution of optical characteristic parameters of the original radiation color developing film and the opaque paper; the opaque paper is preferably opaque black paper;

[0050] Step S100 specifically includes:

[0051] Step S110: Obtain the brightness information and two-dimensional distribution of the optical density value of the original radiation chromogenic film; specifically, use a scanner and a densitometer to obtain the two-dimensional distribution of the RGB value and optical density value of the original radiation chromogenic film that has not been irradiated by laser; first, place the original radiation chromogenic film that has not been irradiated by laser flat on the detection platform of the scanner to ensure that the film is wrinkle-free, stain-free and completely covers the detection area; after starting the scanning program, the light source of the scanner emits light to illuminate the original radiation chromogenic film, and the light reflected by the original radiation chromogenic film is received by the photoelectric sensor and converted into a digital signal, and the two-dimensional distribution data of the RGB value of the original radiation chromogenic film is obtained after processing; the densitometer emits a light beam with a specific intensity and spectral distribution through the original radiation chromogenic film according to its standard measurement process, and calculates the two-dimensional distribution data of the optical density value by detecting the transmitted light intensity and combining with the built-in algorithm and stores it;

[0052] Step S120: Obtain the two-dimensional distribution of the brightness information of the opaque paper; specifically, opaque light paper The opaque paper generally refers to a paper material with extremely low transmittance to visible light, and its material is specially treated, such as the surface is coated with a light-absorbing material or it is composed of a multi-layer structure, which can effectively block the penetration of light. In this measurement method, the brightness information of the opaque paper is mainly used as a background reference and interference source identification. Although the opaque paper is theoretically opaque, it may have a certain brightness signal due to weak reflection, scattering or the influence of ambient light in the actual measurement environment. In the measurement of large-aperture nanosecond pulse laser flux, these brightness signals from the opaque paper may interfere with the analysis of the measurement results of the radiochromic film, especially under the measurement requirements of high spatial resolution, even a small interference may cause measurement errors. By obtaining the two-dimensional distribution of the brightness information of the opaque paper, it can be deducted as a background signal in the subsequent measurement data processing of the radiochromic film, thereby improving the accuracy and precision of the measurement, and more accurately obtaining the real effect of laser irradiation on the radiochromic film. Furthermore, when analyzing the changes in the optical properties of radiochromic films caused by laser irradiation, the background brightness interference caused by opaque paper can be effectively eliminated, thereby improving the accuracy and reliability of the entire large-aperture nanosecond pulse laser flux measurement, and making the measurement results more truly reflect the interaction between the laser and the radiochromic film, especially in high spatial resolution measurement scenarios, which helps to accurately identify and locate subtle distribution changes of the laser flux on the film.

[0053] Step S200: placing the radiochromic film in the optical path, and sequentially irradiating different positions of the radiochromic film with a plurality of groups of different laser flux beams;

[0054] Step S200 specifically includes:

[0055] Step S210: placing the radiation chromogenic film in the optical path, and calibrating the laser spot to be measured; specifically, first, according to the experimental design and the expected laser irradiation range and accuracy requirements, select the radiation chromogenic film of appropriate size and specification; the radiation chromogenic film can be placed on the carrying platform in the laser optical path; then, turn on the laser light source, and emit a low-power guide laser beam for spot positioning and optical path calibration, so that the laser spot is completely within the effective range of the radiation chromogenic film; in this embodiment, the image information fed back by the spot detection sensor can be used to adjust the spot position through computer control software or manual operation, so that the laser can accurately act on the predetermined area of ​​the radiation chromogenic film, avoiding the situation where the irradiation data is inaccurate or part of the film area is not effectively irradiated due to the deviation of the spot position, thereby ensuring the integrity and reliability of the measurement data, which is conducive to improving the precision and accuracy of the entire large-aperture nanosecond pulse laser flux measurement;

[0056] Step S220: Based on the preset interval and using multiple groups of different laser flux beams, perform a single radiation operation on the radiation chromogenic film in sequence; specifically, the number of beams should be increased as much as possible to ensure the accuracy of subsequent fitting, and the preset interval is based on preventing crosstalk between irradiation spots; the required multiple groups of different laser flux values ​​are determined according to the experimental plan, and the laser flux value can be adjusted by the laser energy adjustment device. Then, according to the preset starting position, the radiation chromogenic film is moved to a suitable position by computer-controlled mobile platform or manual adjustment to ensure that each laser irradiation is performed at a different predetermined position of the film; a laser beam is emitted to irradiate the radiation chromogenic film once, and the position information and laser flux parameters of this irradiation are recorded; after the irradiation is completed, the laser flux value is adjusted again, and the radiation chromogenic film is moved to the next position to be irradiated according to the preset interval. The preset interval can be determined according to factors such as the size of the laser spot, the divergence angle of the laser, and the photosensitivity characteristics of the film to ensure that the distance between adjacent irradiation spots is not less than several times the spot diameter to prevent crosstalk. By repeating the above steps, the laser flux is continuously changed and the film position is moved until the operations of all predetermined laser flux groups and irradiation positions are completed.

[0057] In this embodiment, a single irradiation operation is performed on the radiochromic film using multiple groups of different laser flux beams based on preset intervals. On the one hand, the increased number of beams can provide abundant data samples, so that there is a more sufficient data basis for subsequent data fitting, thereby improving the accuracy and reliability of the fitting curve, and more accurately reflecting the relationship between the laser flux and the change in the optical properties of the radiochromic film. On the other hand, a reasonable preset interval effectively prevents crosstalk between irradiation spots, ensures the independence and accuracy of data in each irradiation area, avoids data confusion and error increase caused by crosstalk, and helps to accurately obtain the distribution information of the laser flux on the radiochromic film at high spatial resolution, thereby improving the spatial resolution and measurement accuracy of the entire measurement method for large-aperture nanosecond pulse laser flux measurement.

[0058] Step S300: pre-processing the irradiated radiochromic film and extracting the spatial distribution of optical characteristic parameters of the pre-processed radiochromic film;

[0059] Step S300 specifically includes:

[0060] Step S310: the irradiated radiochromic film is stored according to preset conditions; specifically, the preset conditions are to store it away from light at room temperature for at least 24 hours; that is, after the irradiation operation of the radiochromic film is completed, it is taken out of the light path and placed in a specially prepared storage container for storage to avoid further influence of environmental factors on the film, so that the photochemical changes of the film after irradiation can be fully stabilized, reduce the measurement uncertainty caused by immediate changes, and provide a stable and reliable sample basis for the subsequent accurate extraction of the spatial distribution of its optical characteristic parameters;

[0061] Step S320: extract and save the brightness information and two-dimensional distribution of the radiation chromogenic film after processing; specifically, the extraction of the brightness information and two-dimensional distribution of the radiation chromogenic film can refer to the relevant content in step S100, and will not be repeated again; extracting and saving the brightness information and two-dimensional distribution of the radiation chromogenic film after processing can comprehensively obtain the changes in the optical properties of the film after laser irradiation; the brightness information reflects the changes in the reflection or transmission characteristics of light in different areas of the film surface, and the optical density value more deeply reveals the changes in the light absorption characteristics of the film caused by laser irradiation; these two-dimensional distribution data are helpful to accurately analyze the microscopic process of interaction between laser and radiation chromogenic film at high spatial resolution, and further improve the accuracy and spatial resolution of large-aperture nanosecond pulse laser flux measurement.

[0062] Step S400: extracting the net optical density distribution before and after irradiation according to the spatial distribution of the optical characteristic parameters of the original radiochromic film, the opaque paper and the pre-processed radiochromic film;

[0063] Step S400 specifically includes:

[0064] Step S410: using the average background fog subtraction method, the net optical density value is calculated according to the relevant parameters of the target laser flux under different irradiation conditions; specifically, the expression of the net optical density value is:

[0065]

[0066] In the formula, netOD represents the net optical density; OD exposed It indicates the optical density value of the radiochromic film after pretreatment; The average optical density of the original radiochromic film; PV exposed RGB values ​​of radiochromic film after preprocessing; Represents the mean RGB value of the original radiochromic film; Represents the mean RGB value of opaque paper; in the calculation process, for the measured RGB values ​​and optical density values, it is also necessary to check whether there are abnormal values ​​or data points with large errors, which may be caused by accidental errors of the measuring equipment or defects of the film itself. If necessary, re-measure or correct the data; to ensure the accuracy of the calculation results, so as to obtain the net optical density values ​​corresponding to each position, and finally form the net optical density distribution data before and after irradiation. This implementation uses the mean background fog subtraction (MBS) method to calculate the net optical density value, which can effectively remove the interference of the original film and the environmental background (with opaque black paper as a reference) on the optical density measurement of the film after irradiation. This method comprehensively considers the relevant parameters under different irradiation conditions, so that the calculated net optical density distribution can more truly reflect the changes in the optical density of the radiochromic film caused by laser irradiation. In high spatial resolution measurements, accurate net optical density distribution data helps to accurately analyze the effect of laser flux at different positions of the film, and improves the accuracy and reliability of the entire laser flux measurement method for the analysis of laser-matter interactions.

[0067] Step S500: Fitting the relationship curve between laser flux and net light density distribution based on the net light density before and after irradiation; specifically, professional mathematical fitting software (such as Origin, Matlab, etc.) can be selected to fit the relationship curve between laser flux and net light density distribution; the net light density distribution data is used as the dependent variable, and the corresponding laser flux data is used as the independent variable, and input into the selected fitting tool; when fitting, different fitting function forms (such as linear function, polynomial function, exponential function, etc.) can be tried according to the data distribution characteristics, and the best fitting function is determined by observing the degree of fit between the fitting curve and the actual data points and the evaluation indicators such as the determination coefficient of the fitting. The subsequent processing of the laser irradiation to be measured is as follows: use the laser to be measured to irradiate the radiochromic film once; after the irradiation is completed, store it in a light-proof environment at room temperature for 24 hours; then use the same measurement method to obtain the two-dimensional distribution of the RGB value and optical density value of the radiochromic film after irradiation, and then calculate the net optical density distribution through the similar net optical density calculation method in step S400; finally, bring the calculated net optical density distribution data into the known laser flux-net optical density relationship curve that has been fitted. According to the functional relationship corresponding to the curve, the laser flux value corresponding to the measured light spot is inferred by calculation, and then the flux distribution of the measured light spot is obtained.

[0068] See also Figure 4 and Figure 5 As shown, the laser flux-net optical density relationship curve under known different wavelengths and pulse widths is recorded in this application. Figure 4 The relationship curve diagram for a given "355nm, 10ns laser irradiation" is recorded in; Figure 5 The relationship curve for a given "532nm, 10ns laser irradiation" is recorded in: Figure 4 and Figure 5 As the curve calibrated in the present invention (i.e., the reference curve), it can be understood that within a certain range, the relationship curve can be approximately a linear relationship, specifically:

[0069] For 355nm, 10ns laser irradiation: R scanning channel netOD = 0.5326×F2+0.3509×F-0.0108; where F is the laser flux, the unit is J / cm 2 ; The coefficient of determination of the fit is R2 = 0.999;

[0070] For 532nm, 10ns laser irradiation: R scanning channel netOD = 0.1017×F2+0.1082×F-0.0068; where F is the laser flux in J / cm 2; The fitting determination coefficient R2 = 0.998; It can be seen that RCF still has a good response at the wavelengths of 355nm and 532nm commonly used in nanosecond lasers; at the same time, RCF has micron-level high resolution, excellent coloring stability, relatively low price, and supports large-diameter beams up to square meters.

[0071] Step S500 constructs a relationship curve between laser flux and net light density distribution by fitting based on the net light density distribution before and after irradiation, and then uses this relationship curve in combination with the processing and data calculation of the film after laser irradiation to be measured, and finally obtains the flux distribution of the measured light spot; fully utilizes a large amount of previous measurement data and accurate fitting relationship, so that the corresponding laser flux distribution can be accurately inferred from the measured changes in the optical properties of the film (net light density distribution), and realizes the effective conversion from measurable optical parameters to the key physical quantity of target laser flux; greatly improves the accuracy and operability of large-aperture nanosecond pulse laser flux measurement, especially under the requirement of high spatial resolution, and can analyze in detail the distribution of laser flux at different spatial positions.

[0072] In summary, the high spatial resolution measurement scheme of large-aperture nanosecond pulse laser flux provided by the present invention is based on the measurement of laser flux distribution by radiochromic film (RCF). RCF is a hundred-micron thick film for quantitative measurement of high-energy photons, including an active layer containing a dye and a polyester substrate; it has micron-level high resolution, excellent coloring stability, and can support a theoretically infinite beam size by splicing multiple films, and has a relatively low price; the inventors have found in actual work that RCF responds reliably to ultrashort lasers and applied it to the measurement of laser energy. Compared with X-rays with wavelengths less than 10nm, common lasers with wavelengths of hundreds of nanometers have lower photon energy, which manifests as 2-4 photon ionization in the process of multi-photon ionization. As the number of photons required for one ionization increases, its probability will drop significantly. The threshold value of RCF coloring through the barrier suppression ionization (BSI) process is Iapp≈3.26×10 10 W / cm 2 ; Ultrashort and intense laser pulses can easily meet the coloring conditions.

[0073] Use a spectrophotometer to scan the absorption curve of the original RCF. Figure 6 shown; from Figure 6 It can be seen that Figure 6When the wavelength is less than 310nm, the OD curve rises rapidly until it exceeds the range; (the larger the OD, the higher the absorptivity and the smaller the transmittance); the 355nm and 532nm commonly used by the nanosecond laser used in this embodiment have relatively low OD values; indicating that the color development mechanism of the 355nm laser is different from that of X-rays; it is understandable that the existing RCF can achieve a high spatial resolution of less than 5μm when used in scenes such as X-rays; this method uses an EPSON scanner with an optical resolution of 6400dpi (the minimum resolvable size is about 4μm); under the test of visible light and near-ultraviolet nanosecond lasers, the minimum resolution obtained by the test is 30lp / mm, about 33μm. The selected radiochromic film (RCF) itself has a high resolution of micrometers, and can achieve a high spatial resolution of less than 5μm when used in scenes such as X-rays. Even though the optical resolution of the EPSON scanner used in this method is 6400dpi (corresponding to a minimum resolvable size of approximately 4μm), the minimum resolution can reach 30lp / mm (approximately 33μm) under visible light and near-ultraviolet nanosecond laser testing, which means that this measurement method can accurately distinguish the spatial distribution of laser flux at the microscopic level. For research scenarios that require a detailed understanding of the interaction between lasers and matter, the characteristics of microscopic transfer of laser energy, etc., this high spatial resolution provides a strong guarantee for obtaining accurate measurement data, and helps to deeply explore the subtle changes and distribution patterns of laser flux.

[0074] The present invention has at least the following beneficial effects:

[0075] (1) Coping with various photon ionization situations: When facing lasers of different wavelengths, whether it is two-photon ionization generated by near-ultraviolet lasers or single-photon ionization generated by far-ultraviolet lasers, this method can be applied and can analyze the contribution of each photon ionization and the intrinsic absorption of the material in the RCF coloring process; the compatibility of this method with lasers of different photon energies and different ionization mechanisms enables it to be widely used in the flux measurement of nanosecond lasers of various wavelengths, broadening the scope of application of the measurement method;

[0076] (2) The measurable flux range corresponding to different wavelengths of lasers is clearly defined, and the measurement range for near-ultraviolet light is 0.02 to 0.8 J / cm 2 The net optical density is approximately linearly related to the laser flux, which is convenient for rough evaluation of the beam before scanning the film and data processing; the measurable range corresponding to 532nm visible light is 0.08~2.0J / cm 2 ; This understanding of the range of laser flux at different wavelengths enables this method to accurately measure lasers at various energy levels. Whether it is a laser with a low flux or a relatively high flux, the corresponding flux distribution information can be effectively obtained to meet the diverse experimental and practical application needs;

[0077] (3) Support for large-aperture beam measurement: By splicing multiple films, RCF can support theoretically infinite beam sizes, and can actually support large-aperture beams up to square meters. This makes the measurement method not limited by the size of the beam aperture, and is particularly suitable for flux measurement scenarios of large-aperture nanosecond pulse lasers. For example, in some large-scale laser processing equipment, large-scale laser scientific research equipment, etc. involving large-aperture laser beams, it can still reliably obtain its flux distribution information, which has strong practicality.

[0078] (4) Simple optical path and reliable information: When acquiring beam information, the optical path is simple and there is no interference from upstream or downstream components. This greatly reduces the various error factors caused by the complexity of the optical path, making the final information such as laser flux highly reliable, ensuring the accuracy and credibility of the measurement results;

[0079] (5) Cost advantage: RCF has a relatively low price. Compared with some other high-precision, high-performance laser measurement components or equipment, using RCF as the beam information receiving end has obvious advantages in cost control. This makes this measurement method easier to accept and adopt in actual promotion and application, whether for large-scale experiments in scientific research institutions or quality inspection in related laser application fields, thus reducing the measurement cost.

[0080] (6) Good coloring stability: RCF's excellent coloring stability ensures the stability of its optical property changes after laser irradiation, which can provide a stable and reliable basis for the subsequent accurate extraction of optical property parameters such as optical density and analysis of laser flux distribution, reducing the measurement error and uncertainty caused by the unstable factors of the material itself, which is conducive to improving the accuracy and repeatability of the entire measurement method;

[0081] In summary, this high spatial resolution measurement method of large-aperture nanosecond pulse laser flux has demonstrated advantages such as good adaptability, high precision and high reliability in the field of laser flux measurement technology, and has high application value.

[0082] See also Figure 2 As shown, the technical solution of the second aspect of the present invention provides a high spatial resolution measurement system for a large-aperture nanosecond pulse laser flux, using the high spatial resolution measurement method for a large-aperture nanosecond pulse laser flux described in the technical solution of the first aspect of the present invention, and the system comprises:

[0083] The first optical characteristic parameter acquisition module is used to obtain the spatial distribution of the optical characteristic parameters of the original radiation chromogenic film and the opaque paper; specifically, the first optical characteristic parameter acquisition module is equipped with a high-precision scanner, and its resolution must be able to distinguish the changes in the microscopic optical characteristics of the radiation chromogenic film; a professional densitometer can accurately measure the optical density values ​​at different positions of the film, and a reflected light measuring instrument is used to measure the reflected light of the opaque paper; the scanner, densitometer and other equipment are connected to the computer, and the corresponding drivers and control software are installed to ensure that the equipment can be parameterized, operated and controlled, and data collected through the computer; for opaque paper, a reflected light measuring instrument can be used, the opaque paper can be fixed on the measuring platform, the angle and position of the measuring instrument probe can be adjusted to be vertically aligned with the paper surface, the reflected light is received after the light is emitted, the reflected light intensity is converted into brightness information, and the two-dimensional distribution of its brightness information is obtained and stored according to the preset sampling points or scanning paths.

[0084] The irradiation device is used to perform single irradiation on different positions of the radiochromic film in sequence using multiple groups of different laser fluxes; specifically, a large-aperture nanosecond pulse laser is used, and multiple groups of different laser flux values ​​are set according to experimental requirements, and the laser flux output by the laser is adjusted by a computer-controlled energy adjustment device; the radiochromic film is placed on a two-dimensional mobile platform, the guide laser is turned on, and the spot detection device is used in combination with the optical path adjustment to make the laser spot completely fall within the range of the radiochromic film, and the spot position and shape are calibrated; then a laser beam of corresponding flux is emitted to perform a single irradiation on the film, and the position, flux and other parameters of this irradiation are recorded. Repeat the above steps, change the flux value and irradiation position in sequence, and complete multiple groups of single irradiation operations on different positions of the film;

[0085] The second optical characteristic parameter acquisition module is used to extract the spatial distribution of the optical characteristic parameters of the radiochromic film after pretreatment; specifically, after the first irradiation is completed, the radiochromic film is placed at room temperature for 24 hours for preservation treatment to stabilize the photochemical changes on the film caused by laser irradiation; then, the operation process of scanning and obtaining the optical density value and the two-dimensional distribution of the RGB value in the first optical characteristic parameter acquisition module is repeated;

[0086] The net optical density distribution extraction module is used to extract the net optical density distribution before and after irradiation according to the spatial distribution of the optical characteristic parameters of the original radiochromic film and the radiochromic film after pretreatment; specifically, the corresponding algorithm program is written according to the calculation formula of the net optical density value, and the optical density mean value, RGB value mean value and RGB value mean value of the opaque paper and other data of the original radiochromic film are retrieved from the computer storage, and the optical density value and RGB value data of the radiochromic film after pretreatment are obtained at the same time, and the program is run to perform point-by-point calculation to obtain the net optical density distribution data of the entire film area, and to perform visual display;

[0087] The curve fitting module is used to fit the relationship curve between laser flux and net light density distribution based on the net light density before and after irradiation; specifically, the net light density distribution data is used as the dependent variable, and the corresponding laser flux data is used as the independent variable, which are imported into the fitting software or program; different fitting function types are tried for fitting operations, and the degree of fit between the fitting curve and the actual data points is observed at the same time, and the quality of the fitting effect is judged by the determination coefficient evaluation index of the fitting, and the parameters of the fitting function are continuously adjusted until the best fitting result with a high fitting determination coefficient and a fitting curve that can well reflect the internal relationship of the data is obtained, and finally the relationship curve expression between the laser flux and the net light density distribution is determined and the relevant parameters and fitting result information are saved.

[0088] The laser flux acquisition module is used to determine the flux distribution of the laser to be measured based on the relationship curve between the laser flux and the net light density distribution; specifically, the laser to be measured is first used to perform a single irradiation on the new radiation color-developing film according to the operating procedures of the previous irradiation device, and the net light density distribution data after the current laser to be measured is obtained through the same preprocessing, acquisition of the spatial distribution of the optical characteristic parameters of the film after irradiation, and calculation of the net light density distribution. Then, the relationship curve expression and parameters between the laser flux and the net light density distribution previously determined by the curve fitting module are called in the computer, and the net light density distribution data measured this time is substituted into the relationship curve expression, and the flux value corresponding to the laser to be measured is inferred in reverse, thereby determining the flux distribution of the laser to be measured.

[0089] The high spatial resolution measurement system for large-aperture nanosecond pulse laser flux provided in this embodiment integrates multiple functional modules, and the modules cooperate with each other to achieve high-precision and high spatial resolution measurement of large-aperture nanosecond pulse laser flux. It can adapt to laser measurement of different flux ranges, and has a simple optical path and reliable results.

[0090] See also Figure 3 As shown, the irradiation device includes a laser 100 and a radiation chromogenic film 200, wherein the laser 100 is arranged at intervals on one side of the radiation chromogenic film 200, and the laser 100 is configured to perform a single irradiation operation on the radiation chromogenic film 200 in sequence based on a preset interval and using a plurality of groups of different laser fluxes; specifically, a laser capable of outputting a large-aperture nanosecond pulse laser is selected, and the pulse width of the output laser needs to be stable at the nanosecond level and have a wide adjustable energy range to meet the requirements of outputting a plurality of groups of different laser fluxes; it should be noted that the laser for calibrating the curve is determined according to the laser to be measured; if the laser to be measured is convenient to use directly (such as a small or medium-aperture laser), the laser to be measured itself is directly used for calibration; if the laser to be measured is a large-aperture laser that is not convenient to use, a small-aperture laser with parameters similar to the laser is selected for calibration;

[0091] The technical solution of the second aspect of the present invention provides an electronic device, comprising: a processor and a memory communicatively connected to the processor; wherein the memory stores instructions executable by the processor, and the instructions are executed by the processor so that the processor can execute the steps of the high spatial resolution measurement method of large-aperture nanosecond pulse laser flux described in the technical solution of the first aspect of the present invention.

[0092] The technical solution of the second aspect of the present invention provides a computer-readable storage medium, on which is stored a program for implementing a high spatial resolution measurement method for a large-aperture nanosecond pulse laser flux. The program for implementing a high spatial resolution measurement method for a large-aperture nanosecond pulse laser flux is executed by a processor to implement the steps of the high spatial resolution measurement method for a large-aperture nanosecond pulse laser flux described in the technical solution of the first aspect of the present invention.

[0093] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0094] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A high spatial resolution measurement method for large-aperture nanosecond pulse laser flux, characterized in that: The method comprises: Obtaining the spatial distribution of optical characteristic parameters of the original radiochromic film and opaque paper; The radiochromic film is placed in the optical path, and different positions of the radiochromic film are irradiated sequentially by using multiple groups of laser beams with different fluxes; Preprocessing the irradiated radiochromic film and extracting the spatial distribution of optical characteristic parameters of the preprocessed radiochromic film; Extract the net optical density distribution before and after irradiation based on the spatial distribution of optical characteristic parameters of the original radiochromic film, opaque paper and pre-treated radiochromic film; The relationship curve between laser flux and net optical density distribution was fitted based on the net optical density before and after irradiation.

2. The measuring method according to claim 1, characterized in that: The spatial distribution of optical characteristic parameters of the original radiochromic film and opaque paper is obtained including: Obtaining the brightness information and two-dimensional distribution of optical density values ​​of the original radiochromic film; Obtain the two-dimensional distribution of brightness information of opaque paper.

3. The measuring method according to claim 1, characterized in that Placing the radiochromic film in the optical path, and using multiple groups of different laser flux beams to sequentially irradiate different positions of the radiochromic film once, including: Place the radiochromic film in the optical path and calibrate the laser spot to be measured; A single irradiation operation is performed on the radiochromic film in sequence based on a preset interval and using a plurality of groups of different laser flux beam pairs.

4. The measuring method according to claim 1, characterized in that: Preprocessing the irradiated radiochromic film and extracting the spatial distribution of optical characteristic parameters of the preprocessed radiochromic film include: The irradiated radiochromic film is stored and processed according to preset conditions; Extract and save the brightness information and two-dimensional distribution of optical density values ​​of the processed radiochromic film.

5. The measuring method according to any one of claims 1 to 4, characterized in that: According to the spatial distribution of optical characteristic parameters of the original radiochromic film, opaque paper and pre-treated radiochromic film, the net optical density distribution before and after irradiation is extracted, including: The net optical density value was calculated using the average background fog subtraction method according to the relevant parameters of the target laser flux under different irradiation conditions.

6. The measuring method according to claim 5, characterized in that: The expression for the net optical density value is: In the formula, netOD represents the net optical density; OD exposed It indicates the optical density value of the radiochromic film after pretreatment; The average optical density of the original radiochromic film; PV exposed RGB values ​​of radiochromic film after preprocessing; Represents the mean RGB value of the original radiochromic film; Indicates the average RGB value of opaque paper.

7. High spatial resolution measurement system for large-aperture nanosecond pulse laser flux, characterized by: The high spatial resolution measurement method of large-aperture nanosecond pulse laser flux according to any one of claims 1 to 6 is adopted, and the system comprises: A first optical characteristic parameter acquisition module is used to acquire the spatial distribution of the optical characteristic parameters of the original radiochromic film and the opaque paper; An irradiation device, used to sequentially irradiate different positions of the radiochromic film with a plurality of different laser fluxes; A second optical characteristic parameter acquisition module is used to extract the spatial distribution of the optical characteristic parameters of the pre-processed radiochromic film; A net optical density distribution extraction module is used to extract the net optical density distribution before and after irradiation according to the spatial distribution of optical characteristic parameters of the original radiochromic film and the radiochromic film after pretreatment; A curve fitting module, used to fit the relationship curve between laser flux and net light density distribution based on the net light density before and after irradiation; The laser flux acquisition module is used to determine the flux distribution of the laser to be measured based on the relationship curve between the laser flux and the net light density distribution.

8. The high spatial resolution measurement system of large-aperture nanosecond pulse laser flux according to claim 7, characterized in that: The irradiation device includes a laser and a radiation chromogenic film. The laser is arranged at intervals on one side of the radiation chromogenic film. The laser is configured to perform a single irradiation operation on the radiation chromogenic film in sequence based on a preset interval and using multiple groups of different laser fluxes.

9. An electronic device, characterized in that: The electronic device includes: a processor and a memory communicatively connected to the processor; wherein the memory stores instructions executable by the processor, and the instructions are executed by the processor so that the processor can execute the steps of the high spatial resolution measurement method of large-aperture nanosecond pulse laser flux as described in any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a program for implementing a high spatial resolution measurement method for a large-aperture nanosecond pulse laser flux, and the program for implementing a high spatial resolution measurement method for a large-aperture nanosecond pulse laser flux is executed by a processor to implement the steps of the high spatial resolution measurement method for a large-aperture nanosecond pulse laser flux as described in any one of claims 1 to 6.

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