Gaussian beam thermal halation effect calculation method and system based on iterative scale law

Abstract

The invention provides a Gaussian beam thermal halo effect calculation method and system based on an iterative scale law, and relates to the technical field of laser atmospheric transmission calculation, and the method comprises the steps: obtaining atmospheric environment parameters and initial light spot size in a current environment; calculating a theoretical light spot size along the z-axis direction according to the initial light spot size and a vacuum diffraction formula; based on the atmospheric environment parameters and the atmospheric aerosol model, the cumulative transmittance along the z axis in the current environment is obtained; substituting the theoretical light spot size into a thermal distortion function, and carrying out iterative updating on the thermal distortion function to obtain a first thermal distortion parameter; calculating a transition light spot size based on the first thermal distortion parameter and a scale law function; and substituting the transition light spot size into the thermal distortion function to obtain a second thermal distortion parameter, and if the difference between the first thermal distortion parameter and the second thermal distortion parameter is smaller than or equal to a preset thermal distortion stable value, outputting the transition light spot size as a target light spot size. According to the invention, the accuracy and efficiency of thermal distortion effect calculation can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser atmospheric transmission calculation, and particularly to a calculation method and system for the thermal blooming effect of Gaussian beams based on an iterative scaling law. Background Art

[0002] During the transmission of high-power lasers, due to atmospheric absorption and refractive index changes, the laser beam will experience the thermal blooming effect, resulting in spot expansion, focal drift, and energy attenuation. Eventually, the power density of the long-exposure spot decreases, affecting the operation of equipment such as laser communication, laser energy transmission, and laser defense equipment. To address the problem of beam expansion caused by thermal blooming, it is necessary to obtain atmospheric optical parameters such as visibility and turbulence structure constant, and then predict and calculate the laser atmospheric to target spot radius a based on the laser atmospheric transmission theory to obtain a reasonable prediction of laser transmission efficiency.

[0003] A Chinese patent with the publication number CN116663289A discloses a method for calculating the transmission process of super-Gaussian beams in free space. The method includes: simulating the transmission process of super-Gaussian beams by calculating the laser transmission wave vector, intuitively calculating the axial and radial components of the spatial light at each point, and accurately obtaining the spot shape and beam quality of the laser after long-distance transmission when it irradiates the target. However, the above solution only relies on the calculation of the laser transmission wave vector, making it difficult to fully simulate the influence of non-ideal factors in complex scenarios, and not making sufficient compensation for environmental interferences such as atmospheric turbulence and scattering, reducing the coincidence degree between the calculation result and the actual situation, and ultimately resulting in low accuracy of the thermal distortion effect calculation. Therefore, it is very necessary to provide a calculation method and system for the thermal blooming effect of Gaussian beams based on an iterative scaling law to improve the accuracy and efficiency of the thermal distortion effect calculation. Summary of the Invention

[0004] In view of this, the present invention proposes a calculation method and system for the thermal blooming effect of Gaussian beams based on an iterative scaling law. By using the real-time monitoring data and the atmospheric environment parameters and spot size information collected by on-site measurement equipment, the matching degree and prediction accuracy of the theoretical model to the actual situation are greatly improved. At the same time, it can quickly converge to a stable state during the iterative update of the thermal distortion function to improve the accuracy and efficiency of the thermal distortion effect calculation.

[0005] The present invention provides a calculation method for the thermal blooming effect of Gaussian beams based on an iterative scaling law, and the method includes:

[0006] Obtain the atmospheric environment parameters and the initial spot size in the current environment;

[0007] According to the initial spot size and the vacuum diffraction formula, calculate the theoretical spot size along the z-axis direction;

[0008] Based on the atmospheric environment parameters and the atmospheric aerosol model, obtaining the cumulative transmittance along the z-axis in the current environment;

[0009] Substituting the theoretical spot size into a thermal distortion function, and iteratively updating the thermal distortion function to obtain a first thermal distortion parameter;

[0010] Calculating a transition spot size based on the first thermal distortion parameter and the scaling law function;

[0011] The transition spot size is re-substituted into the thermal distortion function to obtain a second thermal distortion parameter. If the difference between the first thermal distortion parameter and the second thermal distortion parameter is less than or equal to a preset thermal distortion stability value, the transition spot size is output as a target spot size.

[0012] On the basis of the above technical solution, preferably, the step of obtaining the cumulative transmittance along the z-axis under the current environment based on the atmospheric environment parameters and the atmospheric aerosol model specifically includes:

[0013] Calculate the atmospheric absorption coefficient, atmospheric scattering coefficient and atmospheric extinction coefficient in the current environment in sequence according to the atmospheric environment parameters;

[0014] Based on the atmospheric absorption coefficient, the atmospheric scattering coefficient and the atmospheric extinction coefficient, a cumulative transmittance function is constructed to obtain the cumulative transmittance along the z-axis under the current environment.

[0015] On the basis of the above technical solutions, preferably, the atmospheric aerosol model includes one or more of aerosol particle size, aerosol number distribution, chemical composition of different types of aerosols, optical refractive index of different types of aerosols, concentration change values of aerosols in different areas, and concentration change values of aerosols in different time periods.

[0016] More preferably, the expression of the thermal distortion function is:

[0017]

[0018] Among them, a vacuum (z) represents the theoretical spot size produced by vacuum diffraction at position z, a d represents the spot size of a Gaussian beam with a radius of a0 focused on the focal plane at position L, a0 represents the radius of the starting position, L represents the propagation distance of the Gaussian beam, λ represents the laser wavelength, τ(z') represents the cumulative transmittance on the integral path, and α ext (z”) represents the extinction coefficient at the z” position, N D_z (z) represents the thermal distortion function integrated from the starting plane to the z position, n tdenotes the derivative of the atmospheric refractive index with respect to temperature, k denotes the wave number of the Gaussian beam, P denotes the power of the Gaussian beam, ρ0 denotes the air density, C p denotes the specific heat capacity at constant pressure, V w (z) denotes the effective wind speed at position z, α abs denotes the absorption coefficient, T0 denotes the atmospheric temperature at the starting position, T(z') denotes the air temperature on the integration path, and a(z') denotes the spot size on the integration path.

[0019] More preferably, the expression of the scaling law function is:

[0020]

[0021] where a(z) denotes the spot size at position z along the laser transmission path, a d denotes the spot size when a Gaussian beam with a radius of a0 is focused on the focal plane at position L, a0 denotes the radius at the starting position, L denotes the propagation distance of the Gaussian beam, A denotes the first undetermined fitting parameter, B denotes the second undetermined fitting parameter, N D_z (z) denotes the thermal distortion function integrated from the starting plane to position z.

[0022] More preferably, both the first undetermined fitting parameter and the second undetermined fitting parameter are determined according to a preset experimental threshold.

[0023] In the second aspect of the present application, a Gaussian beam thermal blooming effect calculation system based on an iterative scaling law is provided. The Gaussian beam thermal blooming effect calculation system includes a data acquisition module, a data processing module, and a parameter optimization module, where

[0024] The data acquisition module is used to obtain the atmospheric environment parameters and the initial spot size in the current environment;

[0025] The data processing module is used to calculate the theoretical spot size along the z-axis direction according to the initial spot size and the vacuum diffraction formula, and based on the atmospheric environment parameters and the atmospheric aerosol model, to obtain the cumulative transmittance along the z-axis in the current environment. Substitute the theoretical spot size into the thermal distortion function and iteratively update the thermal distortion function to obtain the first thermal distortion parameter;

[0026] The parameter optimization module is used to calculate the transition spot size based on the first thermal distortion parameter and the scaling law function, substitute the transition spot size back into the thermal distortion function to obtain the second thermal distortion parameter. If the difference between the first thermal distortion parameter and the second thermal distortion parameter is less than or equal to a preset thermal distortion stability value, then output the transition spot size as the target spot size.

[0027] In a third aspect of the present application, an electronic device is provided, including a processor, a memory, a user interface, and a network interface. The memory is used to store instructions, the user interface and the network interface are used to communicate with other devices, and the processor is used to execute the instructions stored in the memory.

[0028] In a fourth aspect of the present application, a computer-readable storage medium is provided, on which a computer program is stored. The computer program, when executed by a processor, implements the steps of a calculation method for the thermal blooming effect of a Gaussian beam based on an iterative scaling law.

[0029] The calculation method and system for the thermal blooming effect of a Gaussian beam based on an iterative scaling law provided by the present invention have the following beneficial effects compared with the prior art:

[0030] (1) By using the real-time monitoring data, the atmospheric environment parameters collected by on-site measurement devices, and the spot size information, the calculation process is based on real environmental conditions, greatly improving the matching degree and prediction accuracy of the theoretical model to the actual situation. Introducing the actually measured atmospheric parameters and the initial spot size into models such as vacuum diffraction can more realistically simulate the propagation characteristics of the beam in a non-ideal, atmospheric environment, providing an accurate basis for the subsequent calculation of the thermal distortion function and the cumulative transmittance, thereby enhancing the reliability of the beam propagation simulation. At the same time, through accurate data collection in the initial stage, it can quickly converge to a stable state during the iterative update of the thermal distortion function, ensuring that the transitional spot size output after the first thermal distortion parameter reaches a steady state is closer to the actual situation, so as to improve the accuracy and efficiency of the thermal distortion effect calculation.

[0031] (2) By comprehensively substituting the theoretical spot size, the spot expansion caused by initial aberration, and atmospheric parameters into the thermal distortion function formula, and using iterative updates to dynamically compensate for the deviation between the initial assumption and the actual thermal effect, the calculation result is closer to the actual situation, thus significantly improving the calculation accuracy of the thermal blooming effect of a Gaussian beam. At the same time, the iterative loop based on the stability judgment of the thermal distortion parameters at the target surface ensures a stable output after a sufficient number of iterations, which not only helps to quickly obtain a convergent result, but also ensures that the calculation terminates after meeting the preset stable conditions, greatly enhancing the stability and reliability of the algorithm. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0033] Figure 1Schematic flow chart of the calculation method of Gaussian beam thermal blooming effect based on iterative scaling law provided by the present invention;

[0034] Figure 2 Schematic diagram of heat transfer of Gaussian beam along the z direction provided by the present invention;

[0035] Figure 3 Schematic diagram of comparison of spot radius under iterative scaling law simulation and strict numerical simulation provided by the present invention;

[0036] Figure 4 Error distribution histogram provided by the present invention;

[0037] Figure 5 Schematic structural diagram of the Gaussian beam thermal blooming effect calculation system provided by the present invention;

[0038] Figure 6 Schematic structural diagram of the electronic device provided by the present invention.

[0039] Description of reference numerals: 1, Gaussian beam thermal blooming effect calculation system; 11, data acquisition module; 12, data processing module; 13, parameter optimization module; 2, electronic device; 21, processor; 22, communication bus; 23, user interface; 24, network interface; 25, memory. Detailed implementation manners

[0040] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0041] The present invention discloses a calculation method of Gaussian beam thermal blooming effect based on iterative scaling law. Refer to Figure 1 , the steps of this method include S1 to S6.

[0042] Step S1, obtain the atmospheric environment parameters and the initial spot size in the current environment.

[0043] In this step, atmospheric environment parameters can be used to collect real-time data such as atmospheric temperature, humidity, air pressure, wind speed, and particulate matter concentration by using atmospheric sensors or weather stations, such as thermometers, hygrometers, barometers, anemometers, and atmospheric particle concentration monitoring instruments. Alternatively, in combination with a pre-established regional atmospheric aerosol model, historical data and on-site real-time data can be used for inversion analysis to obtain cumulative transmittance, turbulence parameters, etc. The initial spot size can be obtained based on the technical parameters of the laser, or the actual emitted beam can be sampled and imaged using a spot meter or beam analyzer to directly measure the initial spot size under the current environment.

[0044] Step S2: Calculate the theoretical spot size in the z-axis direction according to the initial spot size and the vacuum diffraction formula.

[0045] In this step, as Figure 1 shown, an iterative method for the spot radius in the z direction is used for estimation. For the spot transmission with thermal blooming effect, layer-by-layer analysis along the direction is carried out according to the scaling law. Then, for the beam radius with thermal blooming, there is a formula:

[0046]

[0047] where a d_z (z) represents the diffraction radius of the Gaussian beam focused on the XY plane at the z position, N D_z (z) represents the thermal distortion coefficient integrated from the starting plane to the XY plane at the z position. A and B represent the undetermined fitting parameters during model training. β 0_z represents the spot expansion multiple caused by the aberration of the initial beam.

[0048] Furthermore, β 0_z (z) represents the spot expansion caused by the aberration of the initial beam. The focusing position of the actually transmitted beam is at L, which can be regarded as the superposition of a beam focused at the z position and a deviation caused by a defocus aberration. Based on the vacuum transmission result of the ideal Gaussian beam then there is:

[0049]

[0050] where L represents the focal plane position of the laser focus, a d represents the spot of the Gaussian beam with a radius of a0 focused on the focal plane at the L position λ represents the laser wavelength, a d_z (z) represents the spot radius at the z position when the Gaussian beam with a radius of a0 is focused at the z position. a vacuum (z) represents the spot radius at the z position when the Gaussian beam with a radius of a0 is focused at the L position. a d_z (z), a d, a vacuum (The relationship with z) is as follows Figure 1 shown

[0051] In this embodiment, by using the initial spot size and the vacuum diffraction formula, and estimating the theoretical spot radius of each layer on the z-axis through layer-by-layer iteration, the diffraction expansion behavior of the Gaussian beam during propagation can be finely characterized, providing a reliable geometric basis for further introducing thermal distortion. The scaling law method is adopted to conduct a layered analysis of the beam transmission with thermal blooming effect, and the spot radius of each layer is compensated by introducing the thermal distortion coefficient, so that the influence of the environmental thermal effect on the optical system can be better reflected during the modeling process. The undetermined fitting parameters (A, B) during model training and the spot expansion multiple caused by the initial beam aberration are introduced, so that the model can be calibrated to be closer to the actual transmission characteristics, improving the overall calculation accuracy and the adaptability under different transmission conditions. By comprehensively considering the ideal beam transmission and the actual influence of the thermal effect, this method provides a theoretical basis for the design optimization and real-time regulation of the optical system, and further helps to improve the system stability and anti-interference ability.

[0052] Step S3: Based on the atmospheric environment parameters and the atmospheric aerosol model, obtain the cumulative transmittance along the z-axis in the current environment.

[0053] In this step, steps S31 to S32 are further included.

[0054] Step S31: Calculate the atmospheric absorption coefficient, atmospheric scattering coefficient, and atmospheric extinction coefficient in the current environment according to the atmospheric environment parameters in sequence.

[0055] Step S32: Based on the atmospheric absorption coefficient, atmospheric scattering coefficient, and atmospheric extinction coefficient, construct a cumulative transmittance function to obtain the cumulative transmittance along the z-axis in the current environment.

[0056] In this step, according to the input atmospheric visibility parameter and the atmospheric aerosol model, calculate the scattering, extinction, and absorption coefficients, and the cumulative transmittance along the z direction is expressed as:

[0057]

[0058] where α ext (z”) is the extinction coefficient at the z” position.

[0059] In this embodiment, the atmospheric aerosol model includes one or more of the aerosol particle size, aerosol number distribution, chemical composition of different types of aerosols, optical refractive index of different types of aerosols, concentration change values of aerosols in different regions, and concentration change values of aerosols at different time periods.

[0060] By calculating the atmospheric absorption, scattering, and extinction coefficients in sequence, the influence of various physical and chemical properties in the atmosphere on beam transmission can be fully considered, providing comprehensive input data for the cumulative transmittance. Using parameters such as particle size, number distribution, chemical composition, optical refractive index, and spatio-temporal concentration changes in the atmospheric aerosol model, accurate modeling of the complexity and dynamic changes of the atmospheric environment is achieved, thus ensuring reliable calculation of the cumulative transmittance under different environmental conditions. Based on the input atmospheric visibility parameters and aerosol characteristics, a cumulative transmittance function is constructed, enabling the transmission characteristics of the beam under different atmospheric states to be captured and corrected in a timely manner, effectively improving the adaptability and prediction accuracy of the optical transmission model in practical engineering applications.

[0061] Step S4: Substitute the theoretical spot size into the thermal distortion function and iteratively update the thermal distortion function to obtain the first thermal distortion parameter.

[0062] In this step, the expression of the thermal distortion function is:

[0063]

[0064] where, a vacuum (z) represents the theoretical spot size generated by vacuum diffraction at position z, a d represents the spot size of a Gaussian beam with a radius of a0 focused on the focal plane at position L, a0 represents the starting position radius, L represents the propagation distance of the Gaussian beam, λ represents the laser wavelength, τ(z') represents the cumulative transmittance on the integration path, α ext (z”) represents the extinction coefficient at position z”, N D_z (z) represents the thermal distortion function integrated from the starting plane to position z, n t represents the derivative of the atmospheric refractive index with respect to temperature, k represents the wave number of the Gaussian beam, P represents the power of the Gaussian beam, ρ0 represents the air density, C p represents the specific heat capacity at constant pressure, V w (z) represents the effective wind speed at position z, α abs represents the absorption coefficient, T0 represents the starting position atmospheric temperature, T(z') represents the air temperature on the integration path, a(z') represents the spot size on the integration path,

[0065] Furthermore, substitute the expression of the spot expansion β 0_z (z) 2 caused by the aberration of the initial beam into the theoretical spot size a(z) 2 expression to obtain:

[0066]

[0067] and substitute into and Simplification gives:

[0068]

[0069] To calculate the theoretical spot size a(z) using the above formula, it is necessary to first calculate the thermal distortion function N D_z (z). And the formula of the thermal distortion function N D_z (z) contains a(z') again. Therefore, iterative loop calculation is adopted.

[0070] The starting parameters used in the first calculation are:

[0071]

[0072] Among them, i represents the number of iterations, and the initial Subsequently, substitute N D_z (z) into a(z) 2 Calculate a new round of a(z, i = 1), and substitute a(z, i = 1) into the thermal distortion function N D_z (z) to calculate the initial Loop like this until the thermal distortion parameters at the target surface reach stability.

[0073] In this embodiment, by comprehensively substituting the theoretical spot size, the spot expansion caused by the initial aberration, and the atmospheric parameters into the thermal distortion function formula, and using iterative update, the deviation between the initial assumption and the actual thermal effect can be dynamically compensated, making the calculation result closer to the actual situation. Thus, the calculation accuracy of the Gaussian beam thermal blooming effect is significantly improved. The iterative loop based on the stability judgment of the thermal distortion parameters at the target surface ensures stable output after a sufficient number of iterations. Such a design not only helps to quickly obtain the convergent result, but also ensures that the calculation terminates after meeting the preset stability conditions, greatly enhancing the stability and reliability of the algorithm. By including various factors such as the theoretical spot size, the initial beam aberration, the cumulative transmittance in the optical path, and the atmospheric temperature and wind speed in the thermal distortion function, the influence of the atmosphere on the beam transmission and thermal effect can be considered more comprehensively, providing a refined model support for practical engineering applications. The iterative update method is applicable to fine optical calculations under complex environmental conditions, providing strong technical support for high-power laser systems or other applications involving beam thermal effects. At the same time, this method can adaptively adjust the thermal distortion compensation model according to the actual environmental parameters, making the design and regulation more accurate.

[0074] Step S5, calculate the transition spot size based on the first thermal distortion parameter and the scaling law function.

[0075] In this step, the expression of the scaling law function is:

[0076]

[0077] Among them, a(z) represents the spot size at the position z along the laser transmission path, and a d represents the spot size of a Gaussian beam with a radius of a0 focused on the focal plane at the position L. a0 represents the radius at the starting position, L represents the propagation distance of the Gaussian beam, A represents the first undetermined fitting parameter, B represents the second undetermined fitting parameter, and N D_z (z) represents the thermal distortion function integrated from the starting plane to the position z. Among them, both the first undetermined fitting parameter and the second undetermined fitting parameter are determined according to the preset experimental threshold.

[0078] Step S6, substitute the transitional spot size back into the thermal distortion function to obtain the second thermal distortion parameter. If the difference between the first thermal distortion parameter and the second thermal distortion parameter is less than or equal to the preset thermal distortion stability value, then output the transitional spot size as the target spot size.

[0079] The principle of this solution is as follows. By iteratively optimizing the thermal distortion parameter (Bradley thermal distortion parameter N D ), and the spot size a(z), the accurate prediction of the influence of the laser beam by thermal blooming is realized.

[0080] Assume that the beam is transmitted from z = 0 to z = L, then the specific detailed implementation steps are as follows:

[0081] Initial estimation: Based on the known initial spot size a0, calculate the beam size a vacuum (z) during the vacuum diffraction process, and estimate the thermal distortion parameter N D accordingly. After the Gaussian beam with a starting position radius of a0 is diffractively transmitted over a distance of L, the radius to the target on the focal plane is Then the spot size along the z-axis direction during the diffractive transmission process is

[0082] Atmospheric transmittance calculation: According to the input atmospheric visibility parameter and the atmospheric aerosol model, calculate the scattering, extinction, and absorption coefficients, and the cumulative transmittance along the z direction:

[0083]

[0084] Among them, α ext (z”) is the extinction coefficient at the position z”.

[0085] Thermal distortion parameter calculation: Use the thermal distortion function to calculate the thermal distortion parameter, and its formula is as follows:

[0086]

[0087] Among them, n TDenote the derivative of the atmospheric refractive index with respect to temperature, \(k\) denote the wave number, \(P\) denote the power, \(V\) w (z) denote the effective wind speed, \(\alpha\) abs (z) denote the absorption coefficient, \(\tau(z)\) denote the integral value of the extinction coefficient, \(T_0\) denote the atmospheric temperature at the starting position, \(T(z')\) denote the air temperature on the integration path, \(a(z)\) denote the spot size on the integration path. When calculating the thermal distortion parameters for the first time, \(a(z)\) is not available yet, and at this time, the transmission result \(a\) in vacuum vacuum (z) is used instead.

[0088] Scaling law calculation: Using the scaling law formula

[0089]

[0090] Calculate the final spot size \(a(z = L)\) under the influence of thermal blooming, where \(A\) and \(B\) are calculation parameters obtained by fitting for specific cases, \(a\) d is the spot size transmitted in vacuum to the target

[0091] Iterative calculation: For the first calculation, use \(a(z)=a\) vacuum (z) to substitute into the thermal distortion parameter formula to calculate \(N\) D_z (z), and then use \(N\) D_z (z) to substitute into the scaling law formula to calculate a new round of \(a(z)\), and so on until the thermal distortion parameter \(N\) at the target surface D_z (z) reaches stability. There are undetermined parameters \(A\) and \(B\) in the scaling law calculation formula, where \(B\) can generally be taken as 2, and \(A\) can be calibrated by experiments or numerical simulations of wave optics.

[0092] In an example, for the calculation of the thermal blooming effect of a Gaussian beam under non-turbulent conditions, assume that there is a laser emission device with a laser of 250 kW power and an emission aperture of 1000 mm, a laser wavelength of 1064 nm, an initial Gaussian radius \(a_0 = 166\) mm, and the atmospheric environment is of the marine aerosol type. Select approximately 10 4 different atmospheric scenarios for calculation verification, where the visibility covers 5 - 23 km; the wind speed covers 2.5 - 30 m / s, the flight speed of the laser tracking target covers 5 - 200 m / s, the target distance covers 1 - 25 km, and the flight altitude covers 0 - 15 km.

[0093] The first step: Calibrate the numerical values of the coefficients \(A\) and \(B\) in the iterative scaling law formula . Generally, \(B\) can be selected as \(B = 2\) according to experience, or more data can be used for undetermined fitting.

[0094] Fitting method 1: Select the conditions of target speed of 0, visibility of 15 km, wind speed of 2.5 m / s, target distance of 10 km, and flight altitude of 0 km to conduct an experiment (or strict numerical simulation of wave optics), and obtain the radius a of the on-target light spot. d = 0.102294323843407 m, N D = 182.9. It can be directly calculated that the undetermined coefficient A in the formula is 0.00752093.

[0095] Fitting method 2: Select 30 experiments (or strict numerical simulation of wave optics) with target speed of 0, visibility of 15 km, wind speed of 2.5 m / s, target distance covering 1 - 25 km, and flight altitude covering 0 - 15 km, obtain 30 groups of on-target light spot radii a(z = L) and thermal distortion coefficients ND, and fit to obtain A = 0.00412405 and B = 2.12619534.

[0096] Step 2: Verify the accuracy of the iterative scaling law calculation.

[0097] For 10 4 different atmospheric scenarios, use the scaling law calculation formula obtained by fitting method 2 to calculate the on-target light spot size and compare it with the wave optics result. The results are as follows Figure 1 shown. The iterative scaling law is in good agreement with the strict wave optics simulation result, and the average relative error is 2.58%. The comparison diagram of the light spot radius between the iterative scaling law simulation and the strict numerical simulation is as Figure 3 shown, and the error distribution histogram is as Figure 4 shown.

[0098] In this embodiment, by using the real-time monitoring data, the atmospheric environment parameters collected by on-site measurement equipment, and the light spot size information, the calculation process is based on the real environmental conditions, greatly improving the matching degree and prediction accuracy of the theoretical model to the actual situation. Introducing the actually measured atmospheric parameters and the initial light spot size into models such as vacuum diffraction can more realistically simulate the propagation characteristics of the light beam in a non-ideal, atmospheric environment, provide an accurate basis for the subsequent calculation of the thermal distortion function and the cumulative transmittance, thereby enhancing the reliability of the light beam propagation simulation. At the same time, through the initial accurate data collection, it can quickly converge to a stable state during the iterative update of the thermal distortion function, ensuring that the transition light spot size output after the first thermal distortion parameter reaches a steady state is closer to the actual situation, so as to improve the accuracy and efficiency of the thermal distortion effect calculation.

[0099] Based on the above method, the embodiment of the present application discloses a Gaussian beam thermal blooming effect calculation system based on the iterative scaling law. Refer to Figure 5, the Gaussian beam thermal blooming effect calculation system 1 includes a data acquisition module 11, a data processing module 12, and a parameter optimization module 13. Among them,

[0100] The data acquisition module 11 is used to obtain the atmospheric environment parameters and the initial spot size under the current environment;

[0101] The data processing module 12 is used to calculate the theoretical spot size along the z-axis according to the initial spot size and the vacuum diffraction formula, and based on the atmospheric environment parameters and the atmospheric aerosol model, to obtain the cumulative transmittance along the z-axis under the current environment, substitute the theoretical spot size into the thermal distortion function, and iteratively update the thermal distortion function to obtain the first thermal distortion parameter;

[0102] The parameter optimization module 13 is used to calculate the transition spot size based on the first thermal distortion parameter and the scaling law function, substitute the transition spot size back into the thermal distortion function to obtain the second thermal distortion parameter. If the difference between the first thermal distortion parameter and the second thermal distortion parameter is less than or equal to the preset thermal distortion stability value, the transition spot size is output as the target spot size.

[0103] In one example, the data processing module 12 is used to calculate the atmospheric absorption coefficient, the atmospheric scattering coefficient, and the atmospheric extinction coefficient under the current environment in sequence according to the atmospheric environment parameters; based on the atmospheric absorption coefficient, the atmospheric scattering coefficient, and the atmospheric extinction coefficient, construct a cumulative transmittance function to obtain the cumulative transmittance along the z-axis under the current environment.

[0104] In one example, the atmospheric aerosol model includes one or more of the aerosol particle size, the aerosol number distribution, the chemical composition of different types of aerosols, the optical refractive index of different types of aerosols, the concentration change value of aerosols in different regions, and the concentration change value of aerosols in different time periods.

[0105] In one example, the expression of the thermal distortion function is:

[0106]

[0107] where, a vacuum (z) represents the theoretical spot size generated by vacuum diffraction at the z position, a d represents the spot size of a Gaussian beam with a radius of a0 focused on the focal plane at the L position, a0 represents the starting position radius, L represents the propagation distance of the Gaussian beam, λ represents the laser wavelength, τ(z') represents the cumulative transmittance on the integration path, α ext (z”) represents the extinction coefficient at the z” position, N D_z (z) represents the thermal distortion function integrated from the starting plane to the z position, n Tdenotes the derivative of the atmospheric refractive index with respect to temperature, k denotes the wave number of the Gaussian beam, P denotes the power of the Gaussian beam, ρ0 denotes the air density, C p denotes the specific heat capacity at constant pressure, V w (z) denotes the effective wind speed at position z, α abs denotes the absorption coefficient, T0 denotes the atmospheric temperature at the starting position, T(z') denotes the air temperature on the integration path, and a(z') denotes the spot size on the integration path.

[0108] In one example, the expression of the scaling law function is:

[0109]

[0110] where a(z) denotes the spot size at position z along the laser transmission path, a d denotes the spot size when a Gaussian beam with a radius of a0 is focused on the focal plane at position L, a0 denotes the radius at the starting position, L denotes the propagation distance of the Gaussian beam, A denotes the first undetermined fitting parameter, B denotes the second undetermined fitting parameter, N D_z (z) denotes the thermal distortion function integrated from the starting plane to position z.

[0111] In one example, the first undetermined fitting parameter is determined according to a preset experimental threshold, and the second undetermined fitting parameter is calibrated according to the numerical simulation of wave optics.

[0112] Please refer to Figure 6 , which provides a schematic structural diagram of an electronic device for an embodiment of the present application. As Figure 6 shown, the electronic device 2 may include: at least one processor 21, at least one network interface 24, a user interface 23, a memory 25, and at least one communication bus 22.

[0113] Among them, the communication bus 22 is used to realize the connection and communication between these components.

[0114] Among them, the user interface 23 may include a display screen (Display), a camera (Camera), and optionally the user interface 23 may further include a standard wired interface and a wireless interface.

[0115] Among them, the network interface 24 may optionally include a standard wired interface and a wireless interface (such as a WI-FI interface).

[0116] Among them, the processor 21 may include one or more processing cores. The processor 21 is connected to various parts within the entire server through various interfaces and lines. By running or executing instructions, programs, code sets, or instruction sets stored in the memory 25, and by invoking the data stored in the memory 25, it performs various functions of the server and processes data. Optionally, the processor 21 may be implemented in at least one hardware form of digital signal processing (DSP), field-programmable gate array (FPGA), or programmable logic array (PLA). The processor 21 may integrate a combination of one or several of a central processing unit (CPU), a graphics processing unit (GPU), and a modem, etc. Among them, the CPU mainly processes the operating system, user interface, application programs, etc.; the GPU is responsible for rendering and drawing the content to be displayed on the display screen; the modem is used to process wireless communication. It can be understood that the above-mentioned modem may not be integrated into the processor 21 and may be implemented separately through a single chip.

[0117] Among them, the memory 25 may include random access memory (RAM) and may also include read-only memory. Optionally, the memory 25 includes a non-transitory computer-readable storage medium. The memory 25 can be used to store instructions, programs, code, code sets, or instruction sets. The memory 25 may include a program storage area and a data storage area. Among them, the program storage area may store instructions for implementing the operating system, instructions for at least one function (such as touch function, sound playback function, image playback function, etc.), instructions for implementing the above-mentioned method embodiments, etc.; the data storage area may store the data involved in the above-mentioned method embodiments. Optionally, the memory 25 may also be at least one storage device located far from the aforementioned processor 21. As Figure 6 shown, the memory 25, as a computer storage medium, may include an operating system, a network communication module, a user interface module, and a Gaussian beam thermal blooming effect calculation method based on iterative scaling law.

[0118] In Figure 6In the electronic device 2 shown, the user interface 23 is mainly used to provide an interface for the user to input and obtain the data input by the user; and the processor 21 can be used to call a calculation method for the Gaussian beam thermal blooming effect based on the iterative scaling law stored in the memory 25. When executed by one or more processors, the electronic device is caused to execute one or more methods as in the above embodiments.

[0119] A computer-readable storage medium stores instructions. When executed by one or more processors, the computer is caused to execute one or more methods as in the above embodiments.

[0120] It should be noted that, for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present application is not limited by the described action sequence, because according to the present application, certain steps can be in other sequences or performed simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present application.

[0121] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0122] In several embodiments provided by the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is only a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection to each other can be through some service interfaces. The indirect coupling or communication connection of the device or unit can be in an electrical or other form.

[0123] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place, or can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0124] In addition, in each embodiment of the present application, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0125] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable memory. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in various embodiments of the present application. The aforementioned memory includes various media that can store program codes, such as USB flash drives, mobile hard disks, magnetic disks, or optical discs.

[0126] The above are only exemplary embodiments of the present disclosure, and the scope of the present disclosure cannot be limited thereby. That is, any equivalent changes and modifications made in accordance with the teachings of the present disclosure still fall within the scope covered by the present disclosure. After considering the specification and the disclosure of the practical truth, those skilled in the art will easily think of other implementation manners of the present disclosure. The present application aims to cover any variations, uses, or adaptive changes of the present disclosure, and these variations, uses, or adaptive changes follow the general principles of the present disclosure and include the common general knowledge or conventional techniques in the technical field not recorded in the present disclosure.

[0127] The above description is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A calculation method for the thermal blooming effect of Gaussian beams based on the iterative scaling law, characterized in that, The method includes: Obtaining the atmospheric environment parameters and the initial spot size in the current environment; Calculating the theoretical spot size in the z-axis direction according to the initial spot size and the vacuum diffraction formula; Obtaining the cumulative transmittance in the z-axis direction in the current environment based on the atmospheric environment parameters and the atmospheric aerosol model; Substituting the theoretical spot size into the thermal distortion function, and iteratively updating the thermal distortion function to obtain the first thermal distortion parameter; Calculating the transition spot size based on the first thermal distortion parameter and the scaling law function; Substituting the transition spot size back into the thermal distortion function to obtain the second thermal distortion parameter. If the difference between the first thermal distortion parameter and the second thermal distortion parameter is less than or equal to the preset thermal distortion stability value, the transition spot size is output as the target spot size.

2. The method for calculating the thermal blooming effect of a Gaussian beam based on the iterative scaling law according to claim 1, wherein The obtaining the cumulative transmittance in the z-axis direction in the current environment based on the atmospheric environment parameters and the atmospheric aerosol model specifically includes: Sequentially calculating the atmospheric absorption coefficient, the atmospheric scattering coefficient, and the atmospheric extinction coefficient in the current environment according to the atmospheric environment parameters; Constructing a cumulative transmittance function based on the atmospheric absorption coefficient, the atmospheric scattering coefficient, and the atmospheric extinction coefficient to obtain the cumulative transmittance in the z-axis direction in the current environment.

3. The method for calculating the thermal blooming effect of Gaussian beam based on the iterative scaling law according to claim 2, characterized in that, The atmospheric aerosol model includes one or more of aerosol particle size, aerosol number distribution, chemical composition of different types of aerosols, optical refractive index of different types of aerosols, concentration change values of aerosols in different regions, and concentration change values of aerosols in different time periods.

4. The calculation method of Gaussian beam thermal blooming effect based on iterative scaling law according to claim 1, characterized in that, The expression of the thermal distortion function is: Among them, a vacuum (z) represents the theoretical spot size generated by vacuum diffraction at position z, a d represents the spot size of a Gaussian beam with a radius of a0 focused on the focal plane at position L, a0 represents the radius at the starting position, L represents the propagation distance of the Gaussian beam, λ represents the laser wavelength, τ(z') represents the cumulative transmittance on the integration path, α ext (z”) represents the extinction coefficient at position z”, N D_z (z) represents the thermal distortion function integrated from the starting plane to position z, n t represents the derivative of the atmospheric refractive index with respect to temperature, k represents the wave number of the Gaussian beam, P represents the power of the Gaussian beam, ρ0 represents the air density, C p represents the specific heat capacity at constant pressure, V w (z) represents the effective wind speed at position z, α abs represents the absorption coefficient, T0 represents the atmospheric temperature at the starting position, T(z') represents the air temperature on the integration path, and a(z') represents the spot size on the integration path.

5. The calculation method of the Gaussian beam thermal blooming effect based on the iterative scaling law according to claim 1, characterized in that, The expression of the scaling law function is: Among them, a(z) represents the spot size at the position z along the laser transmission path, a d represents the spot size of a Gaussian beam with a radius of a0 focused on the focal plane at the position L, a0 represents the radius at the starting position, L represents the propagation distance of the Gaussian beam, A represents the first undetermined fitting parameter, B represents the second undetermined fitting parameter, N D_z (z) represents the thermal distortion function integrated from the starting plane to the position z.

6. The method for calculating the thermal blooming effect of a Gaussian beam based on the iterative scaling law according to claim 5, wherein Both the first undetermined fitting parameter and the second undetermined fitting parameter are determined according to the preset experimental threshold.

7. A Gaussian beam thermal blooming effect calculation system based on an iterative scaling law, characterized in that, The Gaussian beam thermal blooming effect calculation system (1) includes a data acquisition module (11), a data processing module (12), and a parameter optimization module (13), where The data acquisition module (11) is used to obtain the atmospheric environment parameters and the initial spot size in the current environment; The data processing module (12) is used to calculate the theoretical spot size in the z-axis direction according to the initial spot size and the vacuum diffraction formula, obtain the cumulative transmittance in the z-axis direction in the current environment based on the atmospheric environment parameters and the atmospheric aerosol model, substitute the theoretical spot size into the thermal distortion function, and iteratively update the thermal distortion function to obtain the first thermal distortion parameter; The parameter optimization module (13) is used to calculate the transition spot size based on the first thermal distortion parameter and the scaling law function, substitute the transition spot size back into the thermal distortion function to obtain the second thermal distortion parameter. If the difference between the first thermal distortion parameter and the second thermal distortion parameter is less than or equal to the preset thermal distortion stability value, the transition spot size is output as the target spot size.

8. An electronic device, characterized in that, It includes a processor (21), a memory (25), a user interface (23) and a network interface (24). The memory (25) is used to store instructions. The user interface (23) and the network interface (24) are used to communicate with other devices. The processor (21) is used to execute the instructions stored in the memory (25) so that the electronic device (2) executes the method according to any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1-6.

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