Propagation properties of radially polarized multi-Gaussian Schell-model beams in oceanic turbulence

Radially polarized cosine non-uniformly correlated beams and their propagation properties

We introduce a kind of radially polarized partially coherent (RPPC) beam with a prescribed non-uniform correlation function, called a radially polarized cosine non-uniformly correlated (RPCNUC) beam. Based on the extended Huygens-Fresnel principle, we study the propagation properties in free space and in a turbulent atmosphere. Unlike RPPC beams with uniform coherence, RPCNUC beams possess the invariance of dark hollow cores and radial polarization, and exhibit self-focusing properties. In a turbulent atmosphere, the intensity distribution demonstrates self-healing properties over a certain propagation distance. We also investigate how to adjust the beam parameters to reduce the turbulence-induced degradation in detail.

Polarization and coherence properties in self-healing propagation of a partially coherent radially polarized twisted beam

With the help of generalized Huygens-Fresnel integral, an analytical expression for the self-healing of a partially coherent radially polarized twisted (PCRPT) beam is derived. The coherence and polarization properties of the PCRPT beam in self-healing propagation are studied in detail. It shows that the existence of the twist phase is a double-edged sword for the self-healing properties of the beam. With the increase of the twist factor, the self-healing ability of beam intensity distribution decreases. However, the anti-disturbance performance of beam polarization improves at the same time. Besides, the polarization and coherence distribution of the beam are proved that own a slight self-healing ability when the obstacle is small. Our results will be helpful to the fields of optical tweezers, microscopy, optical communication, and so on.

Twisted electromagnetic elliptical multi-Gaussian Schell-model beams and their transmission in random media

We extend the scalar elliptical multi-Gaussian Schell-model (EMGSM) beams with twist phase to the electromagnetic domain and obtain the analytical expression for the propagation of the electromagnetic twisted EMGSM beams through random media. The twist phase-induced changes of the spectral density and degree of polarization of such beams on propagation are studied numerically. Results show that by adjusting the twist factor and the correlated parameters of the source, both the spectral density and degree of polarization not only rotate around the propagation axis but also exhibit diverse shapes. The flattopped ellipse-like and diamond-like shape maintain over a relatively long propagation distance and finally involve into Gaussian-like shape due to stronger atmospheric turbulence. The results will be useful in optical trapping and optical communication.

Multi-Gaussian correlated Hankel-Bessel beam properties in anisotropic oceanic turbulence

We introduce the model of a multi-Gaussian correlated Hankel-Bessel (MGCHB) beam generated by a multi-Gaussian Shell-model source and investigate the properties of the beam in anisotropic oceanic turbulence. Under Rytov approximation, the detection probability of the MGCHB beam and the channel capacity with MGCHB beams are derived; both the influence of oceanic turbulence and initial beam parameters on them are discussed by numerical simulations. The results show that the increase of the dissipation rate of kinetic energy per unit mass of fluid, the anisotropic coefficient, and the inner scale factor, as well as the decrease of the dissipation rate of mean-squared temperature and the temperature-salinity contribution ratio, can significantly improve the detection probability and the channel capacity. The results also indicate that the MGCHB beam is a better candidate than an Airy vortex beam for mitigating the influence of oceanic turbulence. Furthermore, smaller topological charge and larger orbital angular momentum modes number are beneficial to improve the detection probability and channel capacity, respectively. Moreover, the performance of the MGCHB beam with longer wavelength, smaller beam index, and larger transverse coherence width is conducive to enhancing the transmission quality through oceanic turbulence.

Multi-hyperbolic sine-correlated beams and their statistical properties in turbulent atmosphere

We introduce a partially coherent beam, called a multi-hyperbolic sine-correlated (MHSC) beam, by employing a multi-hyperbolic sine function to modulate the spectral degree of coherence. Based on the extended Huygens-Fresnel principle and second-order moments of the Wigner distribution function, we derive the analytical expressions for the spectral intensity, the root-mean-square (rms) angular width and the M² factor in turbulent atmosphere. Numerical results show that the intensity profile, which keeps the dark-hollow invariant in free space, will be gradually destroyed by the turbulence along the propagation distance. We believe that the MHSC beams have significant advantage over the hyperbolic sine-correlated beams for reducing the turbulence-induced degradation, especially for the MHSC beams with a higher beam order N. The effects of the beams parameters and the turbulent atmosphere on the beam quality are analyzed in detail.

Propagation of radially polarized Hermite non-uniformly correlated beams in a turbulent atmosphere

We study the propagation properties of a recently introduced class of structured beams, radially polarized Hermite non-uniformly correlated (RPHNUC) beams, in a turbulent atmosphere using the extended Huygens-Fresnel integral and investigate how the mode order and coherence width play a role in resisting the degradation and depolarization effects of the turbulence. In contrast with conventional vector partially coherent beams (PCBs) with uniform (Schell-model) correlation structure, the interaction of the non-uniform correlation structure and non-uniform polarization gives these beams the ability to self-heal their intensity distribution and polarization over certain propagation ranges in turbulence. These properties suggest that RPHNUC beams may be useful in a number of applications, in particular optical trapping and free-space optical communications.