Research On The Propagation Characteristics Of Anomalous Vortex Beams In Ocean Turbulence

Vortex beams are widely used in the fields of laser communication and optical manipulation due to their characteristic of carrying orbital angular momentum,and have extremely high application prospects.The anomalous vortex beam will degenerate into a Quantum Laguerre-Gaussian beam after it travels for a certain distance in the medium,so it has a longer transmission distance than the ordinary vortex beam and is more attractive in the field of underwater communication.In the thesis,the modified ocean optical turbulence spectrum model is combined with the generalized Huygens-Fresnel principle to study the transmission characteristics of anomalous vortex beams in underwater turbulence,and design experiments to explore the effects of temperature turbulence and salinity turbulence on anomalous vortices.The effect of rotating beam transmission characteristics.The main research contents are as follows:1.By combining the oceanic turbulence spatial power spectrum model with the generalized Huygens-Fresnel principle,the propagation characteristics of anomalous vortex beams in isotropic oceanic turbulence are studied.The changes of light intensity of anomalous vortex beams after passing through isotropic turbulence are analyzed.The results show that the initial dark hollow center of the anomalous vortex beam is gradually lost with the increase of the beam propagation distance,and finally degenerates into a Gaussian beam when the beam propagates for 150 m,and produces a larger spot in the far field.2.Based on the modified ocean optics turbulence spectrum model,the changes of the light intensity and phase of anomalous vortex beams after layered ocean turbulence are studied.The results show that in the modified ocean optical turbulence spectrum model,when the ocean turbulence is in an unstable stratified state,the influence of salinity-driven ocean turbulence on the transmission of anomalous vortex beams is significantly greater than that of temperature-driven ones;the phase distribution of anomalous vortex beams Affected by ocean turbulence,the degeneration speed of the bright spot from quadruple to circular is changed.3.An experimental system for simulating underwater turbulence was established,and the effects of underwater turbulence on the scintillation index,beam drift and beam intensity of anomalous vortex beams were studied.Under a certain transmission distance,different salinities in simulated turbulence were discussed.The effects of temperature difference and temperature difference on the scintillation index,beam drift and beam intensity of anomalous vortex beams.The experimental results show that the temperature-driven and salinity-driven underwater turbulence has a great influence on the light intensity in the transmission of the anomalous vortex beam;the variance of the spot drift and the scintillation index of the anomalous vortex beam in the underwater turbulent transmission are generated along with the The water turbulent temperature difference or salinity difference varies,and the influence of salinity-driven underwater turbulence on the variance and scintillation index of anomalous vortex beam spot drift is significantly greater than that of temperature-driven.In the thesis,the anomalous vortex beam has a certain significance for the realization of longer laser communication and target detection in the field of underwater optics.