Research On The Modulation Of The Propagation Phase Of Vortex Beam By Plane Acoustic Wave Disturbing The Local Atmosphere

It is significant to study the use of acoustic waves to actively control the local atmosphere and influence the optical transmission characteristics in the atmospheric channel.This thesis mainly studies the influence of vortex beam on its phase transmission characteristics when it passes through the homogeneous,inhomogeneous atmosphere and atmospheric turbulence disturbed by plane acoustic waves,so as to achieve the purpose of using acoustic waves to control the phase transmission characteristics of vortex beam and the main work includes.1.The relationship between the refractive index of the homogeneous atmosphere and the sound pressure is derived.The distribution of the refractive index of the homogeneous atmosphere under the disturbance of different sound sources is numerically simulated.The influence of the amplitude and frequency of the sound pressure of different sound sources on the distribution of the atmospheric refractive index is analyzed;The relationship between the refractive index of the inhomogeneous atmosphere and the sound pressure of the plane acoustic wave is derived.The influence of the change of the frequency and the amplitude of the plane acoustic wave on the distribution of the refractive index of the inhomogeneous atmosphere is numerically simulated at a small scale angle;Based on the microstructure of atmospheric turbulence refractive index,the structure constant of atmospheric turbulence refractive index after plane sound disturbance is derived,and the intensity distribution of local atmospheric turbulence after plane acoustic waves disturbance is numerically simulated.2.The change of optical path and phase of plane light wave disturbed by plane acoustic wave is studied,and the transmission model of plane light wave through atmospheric medium disturbed by plane acoustic wave is established.The change of optical path and phase of plane light wave after plane acoustic wave perturbs homogeneous and inhomogeneous atmosphere is calculated numerically,and the imfluence of different acoustic wave frequency and sound pressure amplitude on the phase of plane light wave is analyzed;Taking Laguerre-Gaussian(LG)beam as an example,the propagation model of LG beam through atmospheric medium perturbed by plane acoustic wave is established,and the influence of propagation distance and propagation height of LG beam from free space into homogeneous and inhomogeneous atmospheric medium perturbed by plane acoustic wave on the propagation phase of LG beam is numerically calculated,and the influence law of plane acoustic wave perturbation on the phase propagation characteristics of LG beam is analyzed and summarized.3.The refractive index power spectrum of atmospheric turbulence disturbed by plane acoustic waves under the joint influence of refractive index and sound energy is derived.According to the power spectrum inversion method,the local atmospheric turbulence disturbed by plane acoustic waves is numerically simulated;The propagation model of LG beam through local atmospheric turbulence disturbed by plane acoustic waves is established.The phase propagation characteristics of LG beam through local atmospheric turbulence disturbed by plane acoustic waves at different propagation heights are studied.The results show that:After the disturbance of the plane sound field,the refractive index distribution of the homogeneous atmospheric medium presents a layer homogeneous periodic distribution;The refractive index of inhomogeneous atmosphere will gradually fluctuate and decrease with the increase of height;When plane acoustic waves disturb the homogeneous atmospheric medium,the isophase surface of plane light waves fluctuates obviously due to the influence of acoustic waves;LG beam phase will rotate and always return to the initial phase;When the plane acoustic wave perturbs the inhomogeneous atmospheric medium,the phase change of the plane light wave will produce regular periodic changes with the change of the acoustic wave,and the optical path is a wavy inclined plane as a whole;The phase of LG beam will still rotate,but its phase will not return to the initial phase;The acoustic wave mainly affects the intensity distribution of atmospheric turbulence by affecting the refractive index,and the sound energy will make the refractive index structure constant of atmospheric turbulence shift in the direction of decreasing with height;When the disturbance of plane acoustic wave is at the wave trough,it will weaken the atmospheric turbulence;When the disturbance of plane acoustic wave is at the wave peak,it will strengthen the atmospheric turbulence;The phase distortion of LG beam is smaller than that of silent wave when the acoustic wave is weakened;The phase distortion of LG beam will increase at the acoustic wave enhancement.