Propagation Property of an Astigmatic sin–Gaussian Beam in a Strongly Nonlocal Nonlinear Media

Kaicheng Zhu,Jie Zhu,Huiqin Tang,Qin Su

doi:10.3390/app9010071

Abstract

Based on the Snyder and Mitchell model, a closed-form propagation expression of astigmatic sin-Gaussian beams through strongly nonlocal nonlinear media (SNNM) is derived. The evolutions of the intensity distributions and the corresponding wave front dislocations are discussed analytically and numerically. It is generally proved that the light field distribution varies periodically with the propagation distance. Furthermore, it is demonstrated that the astigmatism and edge dislocation nested in the initial sin-Gaussian beams greatly influence the pattern configurations and phase singularities during propagation. In particular, it is found that, when the beam parameters are properly selected, a vortex beam with perfect doughnut-shaped profile can be obtained for astigmatic sin-Gaussian beams with two-lobe pattern propagating in SNNM.

Highlights

In the past decades, self-trapped optical beams in nonlocal nonlinear media, especially in strongly nonlocal nonlinear media (SNNM), have been a topic of considerable interest due to their theoretical importance and many experimental observations [1,2]
The propagation of astigmatic sin-Gaussian beams in SNNM is investigated in detail
The effect of astigmatism embedded in the input sin-Gaussian beams on the propagation properties is discussed analytically and numerically

Summary

Introduction

Self-trapped optical beams in nonlocal nonlinear media, especially in strongly nonlocal nonlinear media (SNNM), have been a topic of considerable interest due to their theoretical importance and many experimental observations [1,2]. Due to the complexity of evolution of beams in the nonlocal domain, it is interesting to find that the changes of wave front dislocations are possible, which turns out to be very important for the propagation characteristics and will modify the pattern structure for a laser beam in SNNM [24,27,28]. Like Hermite-Gaussian beams, sin-Gaussian beams carrying edge dislocations are the special case of the Hermite-sinusoidal-Gaussian beams whose propagation dynamics through various optical systems had been studied widely [29–37]. Our results show some novel variations of wave front dislocations occur for astigmatic sin-Gaussian beams propagating in SNNM.

Theoretical Formulation

Findings

Conclusions