Topic
Bessel beam
About: Bessel beam is a research topic. Over the lifetime, 1946 publications have been published within this topic receiving 42264 citations.
Papers published on a yearly basis
Papers
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10 Oct 2019
TL;DR: In this article, a first lens group (21), an axicon lens (10), and a second lens group(22) are used to detect a laser beam incident on the first lens.
Abstract: This optical device (1a) is provided with a first lens group (21), an axicon lens (10), and a second lens group (22). A laser beam is incident on the first lens group (21). The laser beam that passes through the first lens group (21) is incident on the axicon lens (10). The laser beam that passes through the axicon lens (10) is incident on the second lens group (22). The first lens group (21) forms a first Bessel beam (A) and a first ring beam (B), and forms a focal surface (f) at which the ring width of the first ring beam (B) is the smallest. The second lens group (22) forms a second ring beam (C) the ring width of which is substantially constant along an optical axis, and forms a second Bessel beam (D).
1 citations
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31 Dec 1899
TL;DR: In this article, the contribution of photovoltaic and diffusion effects in the formation of 1D and 2D holographic gratings by Bessel beam technique in photorefractive Fe doped lithium niobate crystals are performed.
Abstract: The study of the contributions of photovoltaic and diffusion effects in the formation of 1D and 2D holographic gratings
by Bessel beam technique in photorefractive Fe doped lithium niobate crystals are performed. For this purpose 1D and
2D gratings were recorded by travelling Bessel beam and counter-propagating Bessel beam (CPBB) techniques using
laser radiation at 532nm wavelength and 17 mW power. Created 1D grating in the form of concentric rings had 9.0μm
period in radial direction. 2D grating which is a combination of annular and planar gratings had a period of 9.0μm in
radial and 266 nm in axial directions. The testing of the profile of the recorded gratings by phase microscope was
performed. The investigations show that the refractive index depth of modulation for 1D annular grating has pronounced
azimuthal dependence as a result of formation of gratings predominantly by the photovoltaic effect taking place along
the C-axis of the crystal. For 2D grating formed by CPBB technique the azimuthal dependence of grating modulation
depth is less pronounced. The 266 nm period in axial direction provides, except for the photovoltaic effect, also the
contribution of the diffusion of charge carriers to the grating formation. Diffusion effect takes place in all directions and
provides the isotropic contribution to the grating formation, but with less efficiency than the photovoltaic effect.
1 citations
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17 Oct 20141 citations
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TL;DR: In this article, the authors demonstrate the use of interference between non-diffracting Bessel beams (BB) to generate a system of optical traps, which offer sub-micron particle confinement, delivery and organization over a distance of hundreds of μm.
Abstract: We demonstrate the use of interference between non-diffracting Bessel beams (BB) to generate a system of optical traps. They offer sub-micron particle confinement, delivery and organization over a distance of hundreds of μm. We analyze system of two identical counter-propagating BBs and the case of two co-propagating BBs with different propagation constants separately. In both of these cases, the interference results in periodic on-axis intensity oscillations involving particle confinement. Altering the phase of one of the interfering beams, the whole structure of optical traps can be shifted axially. Implementing this conveyor belt enables the particle delivery over the whole distance where the optical traps are strong enough for particle confinement. Experimentally we succeeded with generation of both of these systems. In case of two counter-propagating BBs we observed a strong sub-micron particle confinement, while in case of co-propagating BBs the confinement was observed only with help of fluid flow against the radiation pressure of both beams.
1 citations
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07 Aug 2020
TL;DR: In this paper, a focal spot-and-focal depth-variable Bessel beam laser processing system and method is proposed to solve the problem that an existing Besselbeam laser Processing system cannot be suitable for processing different hole patterns and material thicknesses.
Abstract: The invention belongs to the field of laser precision manufacturing and to a focal spot-and-focal depth-variable Bessel beam laser processing system and method and aims to solve the problem that an existing Bessel beam laser processing system cannot be suitable for processing different hole patterns and material thicknesses. The system comprises a laser, a beam expander, a diaphragm, a wave plate,a zoom lens, a positive axis pyramid and a lens, wherein the beam expander, the diaphragm, the wave plate, the zoom lens, the positive axis pyramid and the lens are sequentially arranged in the emergent light path of the laser; a light beam emitted from the laser is expanded and homogenized by the beam expander; the laser beam enters the diaphragm to be subjected to stray light filtering; after the filter laser beam reaches the wave plate and then enters the zoom lens, the focal length of the zoom lens and the distance between the zoom lens and the positive axis pyramid are adjusted, so thatthe focal spot and focal depth of the generated Bessel beam can be changed, and therefore, a required processing light beam is obtained; the light beam acts on the surface of a workpiece after being focused by the lens. By means of the system, the focal spot and focal depth changes of the processing Bessel beam can be realized, the multi-purpose processing of large-depth-diameter-ratio micropores,transparent materials and the like is achieved, and guarantees are provided for high-precision micropore pattern manufacturing, high-quality transparent material cutting and the like.
1 citations