Optical waveguiding by necklace and azimuthon beams in nonlinear media

Abstract

Nonlinear necklace and azimuthon beams were experimentally generated in a self-focusing bulk photorefractive nonlinear medium (crystal SBN:60) using a frequency-doubled Nd:YVO 4 laser at 532 nm. The parallel optical waveguides induced by such a beam were probed by near-infrared signal beams emitted by a Ti:Sapphire laser. The quality and time stability of the guided sub-beams at the exit of the crystal were investigated. In view of the waveguides' ordering along a ring, the best matching probe beams were found to be singly or doubly charged optical vortex bright rings. The results indicate the feasibility of parallel all-optical guiding of optical signals at wavelengths, for which the nonlinear medium is not photosensitive.

Controllable beam reshaping by mixing square-shaped and hexagonal optical vortex lattices

“…in (photorefractive) nonlinear media (see, e.g. 14 ,) and may appear applicable for orbital angular momentum multiplexing of information 16 for data transfer using complex optical fields 17–21 .…”

“…The results in 13 confirmed that the focal (artificial far-field) patterns of 2-D nonlinear photonic lattices of different symmetries provide the necessary initial conditions for creating optically induced waveguides in photorefractive media. In addition to the intriguing physics involved in OV lattice creation and manipulation, such possible applications (see also 14,15 ) as well as the rapidly growing interest in orbital angular momentum multiplexing of information 16 for data transfer using complex optical fields 17–21 stimulated the work presented in the following. Last but not least, the trend towards miniaturization resulting in the development of isolated OV emitter based on microring resonator 22 has recently lead to the demonstration of an on-chip hexagonal OV lattice emitter based on three-plane-wave interference of light coming from parallel waveguides with etched tilt gratings 23 .…”

Focal beam structuring by triple mixing of optical vortex lattices

“…photorefractive nonlinear media; see e.g. Stoyanov et al 2017), multiplexing data transfer using complex singular beams (Li and Wang 2017;Wang et al 2019), and creation of singular higher-order vector fields (Otte et al 2017). For stimulated emission depletion (STED) microscopy, a potential modification (Xue and So 2018) could be based on the arrays of bright beams discussed in this work (with or without OVs nested in), in order to parallelize the scanning of adjacent sectors of one sample.…”

Far-field beam reshaping by manipulating the topological charges of hexagonal optical vortex lattices

“…The results in [32] proved that the focal (artificial far-field) patterns of 2D nonlinear photonic lattices of different symmetries provide suitable initial conditions for writing optically induced waveguides in photorefractive crystals. Besides the interesting physics involved in OV lattice generation and manipulation, it is the latter type of possible applications (see also [33,34]) which stimulated the work presented in this study.…”