Bessel beam

About: Bessel beam is a research topic. Over the lifetime, 1946 publications have been published within this topic receiving 42264 citations.

Light propagation in optically induced Fibonacci lattices

Abstract: We report on the optical induction of Fibonacci lattices in photorefractive strontium barium niobate by use of Bessel beam waveguide-wise writing techniques. Fibonacci elements A and B are used as lattice periods. We further use the induced structures to execute probing experiments with variously focused Gaussian beams in order to observe light confinement owing to the quasiperiodic character of Fibonacci word sequences. Essentially, we show that Gaussian beam expansion is just slowed down in Fibonacci lattices, as compared with appropriate periodic lattices.

Optical lining of dielectric particles by two counter-propagating All-Fiber Bessel-like beams

Abstract: Optical lining of multiple dielectric beads was experimentally demonstrated using two counter- propagating Bessel-like beam generated by multimode interference in optical fibers embedded in polydimethylsiloxane (PDMS) channel. All Fiber Bessel-like beam (AFB) generator was composed of a single mode fiber concatenated with a segment of coreless silica fiber of 1600 μm length and a fiberized focusing lens. A Bessel-like beam was achieved by multimode interference along the coreless silica fiber, and it maintained an average center beam diameter of 3.7 μm over an axial length of 300 μm, having a nearly uniform output power within a variation of ±0.11%. AFB generator was designed to be compatible with a continuous wave Yb-doped fiber laser oscillating at the wavelength of 1084nm in order to provide all-fiber solution. A micro-fluidic system of cross-channel was fabricated using PDMS to embed two counter-propagating fiber probes, which provided an accurate beam alignment and stable delivery of sample. One dimensional optical potential well was generated along the counter propagating beams, where samples were trapped, and then self-optical line of them was formed along longitudinal axis. This results from self-reconstruction, which is property of Bessel beam and it was confirmed in not only dielectric particles but also biological sample. This AFB generator paves the way for novel integration of microfluidic system as optical filter or chromatography.

Laser-induced Bessel beams can realize fast all-optical switching in gold nanosol prepared by pulsed laser ablation

Abstract: We demonstrate the possibility of realizing, all-optical switching in gold nanosol. Two overlapping laser beams are used for this purpose, due to which a low-power beam passing collinear to a high-power beam will undergo cross phase modulation and thereby distort the spatial profile. This is taken to advantage for performing logic operations. We have also measured the threshold pump power to obtain a NOT gate and the minimum response time of the device. Contrary to the general notion that the response time of thermal effects used in this application is of the order of milliseconds, we prove that short pump pulses can result in fast switching. Different combinations of beam splitters and combiners will lead to the formation of other logic functions too.

Numerical study of the Bessel beams carrying optical vortices propagating in turbulent atmosphere

Abstract: In this paper, the aperture averaged scintillations of the Bessel beams carrying optical vortices propagating in turbulent atmosphere are evaluated. The multistep form of the propagation algorithm and a numerical phase screen simulation method are applied to the calculations of the aperture averaged scintillation. The results show that the Bessel beam with more topological charges delivers the smaller scintillation. The relation between the aperture averaged scintillation and the size of the beams is investigated. The effect of inner and outer scales of turbulence on the scintillations of the Bessel beams is also studied. These results may be useful in long-distance optical communications in free space or in turbulent atmosphere.

Parabolic propagation-invariant optical beams

Abstract: We present in this work the propagation-invariant optical fields (PIOFs) which are exact solutions of the Helmholtz equation. These solutions are given in parabolic coordinates and have an inherent parabolic geometry. Our new approach allowed to obtain the proper solutions that describe the whole family of parabolic PIOFs in a straightaway manner. Based on the McCutchen theorem we have also identified the corresponding angular spectrum, which common to all PIOFs, lies on a ring. Another interesting features of these beams is that their order is not quantised as occurs for the Bessel and Mathieu beams and that they have a definite parity.