CN-122021116-A - Super-continuum spectrum laser atmosphere transmission halation effect numerical simulation method based on fluctuation optics

CN122021116ACN 122021116 ACN122021116 ACN 122021116ACN-122021116-A

Abstract

The invention discloses a super-continuum spectrum laser atmospheric transmission halation effect numerical simulation method based on fluctuation optics, which relates to the technical field of high-power super-continuum spectrum laser and high-power broad spectrum laser in free space transmission, and is based on a line-by-line accumulation method of energy accumulation thermal effect to generate a super-continuum spectrum laser comprehensive halation phase screen, and far-field light intensity distribution is obtained by solving a paraxial fluctuation equation and a radiation transmission equation, so that numerical simulation of the super-continuum spectrum laser atmospheric transmission halation effect is realized.

Inventors

Luo Chuankai
QIAN XIANMEI
ZHU WENYUE
WU PENGFEI
LIU QIANG

Assignees

中国科学院合肥物质科学研究院

Dates

Publication Date: 20260512
Application Date: 20251225

Claims (10)

1. A supercontinuum laser atmosphere transmission halation effect numerical simulation method based on fluctuation optics is characterized by comprising the following steps: S1, determining characteristic parameters of a supercontinuum laser source; s2, determining atmospheric condition parameters on a laser transmission path, and calculating an atmospheric extinction profile and an atmospheric absorption profile based on the atmospheric condition parameters; S3, gridding the transmitting plane and the receiving plane, constructing a light source numerical model, inputting characteristic parameters of a light source, and outputting the characteristic parameters as light intensity distribution of supercontinuum laser at the transmitting plane; S4, accumulating energy deposition along the wind speed direction based on a voltage stabilizing approximation assumption, calculating to obtain the density fluctuation caused by heating air by laser, and calculating to obtain the refractive index fluctuation based on Gladstone-Dale law; s5, aiming at different wavelength components in the supercontinuum laser, converting the refractive index fluctuation into phase fluctuation, and taking the phase fluctuation as phase distortion caused by a thermal halo effect on the laser at the current transmission interval; S6, solving a paraxial wave equation, calculating to obtain complex amplitude distribution at the current transmission distance based on complex amplitude distribution at the last transmission distance by adopting a Fourier transform method, and calculating to obtain light intensity distribution at the current transmission distance; and S7, repeating the steps S4-S6 until the laser is transmitted to the target distance to obtain the total light intensity distribution of the supercontinuum laser.
2. The method for simulating the atmospheric transmission halation effect value of the supercontinuum laser based on the fluctuation optics according to claim 1, wherein in the step S4, the density fluctuation amount is calculated as follows: Wherein, the The ratio of the specific heat of air constant pressure to the specific heat of constant volume; And The constant pressure specific heat and the constant specific heat of air are respectively; Is the absorption coefficient; Is the sound velocity; Is the wind speed; for the current transmission plane A light intensity distribution at the location; representing the position coordinates of the current transmission plane; Is the air density fluctuation amount distribution of the current transmission plane.
3. The method for simulating the atmospheric transmission halation effect value of the supercontinuum laser based on the wave optics according to claim 1, wherein in the step S4, the refractive index fluctuation amount is calculated as follows: Wherein, the The air density fluctuation quantity distribution of the current transmission plane is obtained; the air refractive index fluctuation of the current transmission plane is used as the air refractive index fluctuation; representing the position coordinates of the current transmission plane; is Gladstone-Dale coefficients.
4. The method for simulating the atmospheric transmission halation effect of the supercontinuum laser based on the wave optics according to claim 1, wherein in the step S5, the phase fluctuation amount is as follows: Wherein, the The air refractive index fluctuation of the current transmission plane is used as the air refractive index fluctuation; The phase fluctuation of the current transmission plane is used as the phase distortion of the laser caused by the thermal halo effect at the current transmission interval; For different wavelengths The wave number of the laser light, Is the laser wavelength; The current transmission interval, i.e. the current transmission distance step size.
5. The method for simulating the atmospheric transmission halation effect of the supercontinuum laser based on the wave optics according to claim 1, wherein the step S6 is specifically as follows: solving paraxial wave equation based on transmission distance Complex amplitude distribution at Calculating to obtain the transmission distance Complex amplitude distribution at : And calculate the transmission distance Light intensity distribution at : Wherein, the And Representing the fourier transform and the inverse fourier transform, respectively; the current transmission interval is the current transmission distance step length; And For the number of waves in space, The spatial frequency in the X-direction is indicated, Representing the spatial frequency in the Y direction; And Respectively the transmission distance And A complex amplitude distribution of the optical field at; Is that A plurality of transmission distances are respectively recorded as ; For transmission distance A light intensity distribution at the location; representing an imaginary number.
6. The method for simulating atmospheric transmission halation effect values of a supercontinuum laser light source based on wave optics according to claim 1, wherein in the step S1, the characteristic parameters of the supercontinuum laser light source comprise a spectral range, a spectral line width, a power spectral distribution, an emission caliber, a total power, an outgoing beam quality factor and a beam waist radius.
7. The method for simulating the atmospheric transmission halation effect of the supercontinuum laser based on the wave optics according to claim 1, wherein in the step S2, the atmospheric condition parameters on the laser transmission path comprise transmission distance, transmission elevation angle, path atmospheric refractive index structure constant profile distribution, path wind speed profile distribution, path temperature profile distribution, near-ground visibility and aerosol type.
8. A readable storage medium, characterized in that it has stored thereon a computer program which, when executed, implements a method for simulating the numerical value of the atmospheric transfer halation effect of supercontinuum laser based on wave optics according to any one of claims 1 to 7.
9. An electronic device, characterized in that the electronic device comprises a processor, a memory and a computer program stored in the memory and capable of running on the processor, wherein the processor realizes the super-continuum spectrum laser atmosphere transmission halation effect value simulation method based on fluctuation optics according to any one of claims 1-7 when executing the computer program.
10. A computer program product comprising computer program/instructions which, when executed by a processor, implement a method for performing the method for simulating the numerical value of the effect of thermal vignetting in supercontinuum laser atmospheric transport based on wave optics as claimed in any one of claims 1 to 7.

Description

Super-continuum spectrum laser atmosphere transmission halation effect numerical simulation method based on fluctuation optics Technical Field The invention relates to the technical field of free space transmission of high-power supercontinuum laser and high-power broad-spectrum laser, in particular to a supercontinuum laser atmosphere transmission halation effect numerical simulation method based on fluctuation optics. Background With the gradual increase of the power of the supercontinuum laser, the influence of the atmospheric medium on the nonlinear halation effect caused by the laser energy absorption is not negligible. The thermal halo effect can lead to distortion and expansion of far-field light spots of laser, and the power density is greatly reduced. The influence of the halation effect is considered, the numerical simulation is carried out on the high-power supercontinuum laser atmosphere transmission process, and the accuracy of supercontinuum laser atmosphere transmission efficiency evaluation can be greatly improved. Supercontinuum laser is a coherent light source with extremely wide spectral bandwidth, and its output spectrum can be extended from ultraviolet, visible light all the way to near infrared and even mid-infrared bands. It is usually generated by the combined action of strong nonlinear effects such as self-phase modulation, four-wave mixing, stimulated raman scattering and the like by the propagation of a narrow-linewidth, short-pulse laser in a nonlinear medium (such as a photonic crystal fiber, a nonlinear crystal or a gaseous medium). The supercontinuum laser has the advantages of high brightness, high coherence, wide band coverage and the like, and has important application value in the fields of precise spectrum measurement, frequency measurement, biological imaging, laser radar, nonlinear optical research and the like. In recent years, with the development of high-power femtosecond laser and novel nonlinear optical fiber, supercontinuum laser is continuously improved in terms of output power, stability and band controllability, and becomes a research hot spot in modern optics. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a super-continuum spectrum laser atmospheric transmission halation effect numerical simulation method based on fluctuation optics, which is based on a line-by-line accumulation method of energy accumulation thermal effect to generate a super-continuum spectrum laser comprehensive halation phase screen, and the numerical simulation of the super-continuum spectrum laser atmospheric transmission halation effect is realized by solving a paraxial fluctuation equation and a radiation transmission equation to obtain far-field light intensity distribution. In order to achieve the above purpose, the present invention adopts the following technical scheme, including: a supercontinuum laser atmosphere transmission halation effect numerical simulation method based on fluctuation optics comprises the following steps: S1, determining characteristic parameters of a supercontinuum laser source; s2, determining atmospheric condition parameters on a laser transmission path, and calculating an atmospheric extinction profile and an atmospheric absorption profile based on the atmospheric condition parameters; S3, gridding the transmitting plane and the receiving plane, constructing a light source numerical model, inputting characteristic parameters of a light source, and outputting the characteristic parameters as light intensity distribution of supercontinuum laser at the transmitting plane; S4, accumulating energy deposition along the wind speed direction based on a voltage stabilizing approximation assumption, calculating to obtain the density fluctuation caused by heating air by laser, and calculating to obtain the refractive index fluctuation based on Gladstone-Dale law; s5, aiming at different wavelength components in the supercontinuum laser, converting the refractive index fluctuation into phase fluctuation, and taking the phase fluctuation as phase distortion caused by a thermal halo effect on the laser at the current transmission interval; S6, solving a paraxial wave equation, calculating to obtain complex amplitude distribution at the current transmission distance based on complex amplitude distribution at the last transmission distance by adopting a Fourier transform method, and calculating to obtain light intensity distribution at the current transmission distance; and S7, repeating the steps S4-S6 until the laser is transmitted to the target distance to obtain the total light intensity distribution of the supercontinuum laser. Preferably, in step S4, the density fluctuation amount is calculated as follows: ; Wherein, the The ratio of the specific heat of air constant pressure to the specific heat of constant volume; And The constant pressure specific heat and the constant specific heat of air are respectively; Is