Study of propagation of vortex beams in aerosol optical medium

Abstract

A theoretical and experimental study of the propagation of vortex laser beams in a random aerosol medium is presented. The theoretical study is based on the extended Huygens-Fresnel principle with the generation of a random field, using the fast Fourier transform. The simulation shows that the stability of vortex beams to fluctuations of an optical medium falls with rising order of optical vortices. Moreover, a coherence length (radius) of the random medium is of great importance. The coherence radius extension affects adversely the conservation of a beam structure in the random medium. During further free-space propagation, increasing coherence enables reduction of the negative effects of fluctuations for beams with high-value topological charges. Experimental studies in the random aerosol medium have shown that at small distances vortex beams mostly demonstrate lower stability than a Gaussian beam. However, at considerable distances, vortex beams start to demonstrate greater stability that may be explained by their capacity to be regenerated after they passed obstacles.

Spatial-Light-Modulator-Based Multichannel Data Transmission by Vortex Beams of Various Orders

“…It can be explained by the fact that, in the second case, two correlation peaks are formed, which leads to a redistribution of the intensity between them and an increase in the fluctuation of the intensity of each correlation peak. However, it should be noted that the value obtained in the case of detection of a single OAM state is much less than the previously obtained value of the scintillation index for the case of OV beams with TCs up to five propagating through the scattering medium and detected without any diffractive multichannel filter [17]. Besides, the value of the scintillation index that is obtained in the case of detection of the superposition of OV beams with different OAM states is comparable to these values.…”

“…where m is an integer value of a topological charge (TC). The convenience of OVs lies in the independence of the field radius, which provides versatility [22][23][24]42] and significant tolerances for aligning the optical system [17,18].…”

“…The method of beam recognition that is based on a multichannel DOE [ 16 ], which can be used both for the recognition of vortex beams [ 17 , 18 ] and arbitrary polarization-phase distributions [ 19 , 20 , 21 ], has a very good potential for mode division multiplexing (MDM) techniques. The idea of recognizing vortex beams using multichannel DOEs was proposed for the first time in works that were devoted to measuring the OAM [ 22 , 23 ].…”

Recent Advances in Generation and Detection of Orbital Angular Momentum Optical Beams—A Review

“…Since laser beams with OAM are of special interest for data channel multiplexing [ 2 , 68 , 69 ]. Many studies are devoted to the propagation of OV beams as in free space [ 70 , 71 , 72 , 73 ] and in optical fibers [ 74 , 75 , 76 ]. To implement multichannel information transfer using OAM, a certain superposition of OVs with a given energy and phase distribution in the transmitter must be excited on the transmitting side, so each mode transmits an independent information signal.…”

Phase memory of optical vortex beams

“…Several reports conjectured that, because they carry OAM, OVs propagate through optical turbulence with less distortion than conventional Gaussian beams 34 – 36 . Other experimental studies have shown that, in comparison with Gaussian beams, OVs are less stable for small propagation distances but they become more resilient over considerable distances 37 . Indeed, there are different criteria for beam stability.…”