Topic
Bessel beam
About: Bessel beam is a research topic. Over the lifetime, 1946 publications have been published within this topic receiving 42264 citations.
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TL;DR: In this article, the total internal reflection of an optical mode with a phase singularity, such as a Bessel beam, can generate evanescent light that displays a rotational property.
Abstract: The total internal reflection of an optical mode with a phase singularity, such as a Bessel beam, can generate evanescent light that displays a rotational property. Notably, using a metallic layer surface, field components extending into the vacuum region have vortex properties besides surface plasmonic features. This vortex retains the phase singularity of the original light, and also maps its associated orbital angular momentum of incident Bessel light of the order l > 0. Additionally to a two-dimensional patterning on the metallic surface, the strongly restricted intensity distribution decays with distance vertical to the metallic surface. The detailed characteristics of this vortex structure depend on the input light parameters and the dielectric mismatch of the media. As well as this, they can be controlled by varying the incident angle and the order of Bessel light.
7 citations
Patent•
13 Jun 2012
TL;DR: In this article, a bessel beam generator based on an annular Dammann gratings is sequentially formed by the annular dammam gratings sharing the same optical axis, a first lens, an amplitude type spatial filter, a second lens and a focusing objective lens.
Abstract: A bessel beam generator based on an annular Dammann gratings is sequentially formed by the annular Dammam gratings sharing the same optical axis, a first lens, an amplitude type spatial filter, a second lens and a focusing objective lens. The first lens and the second lens are a confocal lens group, each annular Dammam grating is first-ordered and multi-cycle and has the two-value phase difference of pi, and the amplitude type spatial filter is located on a confocal plane of the first lens and the second lens. Diffraction-free light beams with micron dimension or submicron dimension crosswise facula and 10-102 wavelength of axial focal depth can be generated in a focusing backfield of the focusing objective lens. Switch efficiency is as high as 80%. By means of a spatial filtering mode, quality of generated bessel beams is further improved. The micron or submicron diffraction-free bessel beam can be widely used in the fields of optical micro-machining, optical storage, large focus depth imaging, laser grain capture and quickening, a self-focusing servo-system and the like.
7 citations
TL;DR: The Fraunhofer diffraction pattern of a narrow annular slit is recorded holographically to generate a beam that approximates a diffraction-free Bessel beam, and this beam is amplified by two-wave mixing in a photorefractive crystal.
Abstract: The Fraunhofer diffraction pattern of a narrow annular slit is recorded holographically to generate a beam that approximates a diffraction-free Bessel beam. The experimental limitations resulting from the annular-slit parameters such as the opening width and the transmission coefficient are discussed. The reconstructed Bessel beam is amplified by two-wave mixing in a photorefractive crystal. Thus the efficient conversion of a relatively large beam with a constant (or Gaussian) intensity distribution into a nondiffracting beam is achieved entirely by direct physical interference. We show that diffraction-free beams reproduced and amplified in this way can be applied to the measurement of the velocity of small objects by the use of the laser Doppler technique. In addition, the advantages of Bessel beams, especially in measuring the velocity of solids, are discussed.
7 citations
TL;DR: In this paper, a new type of Bessel-like beam which can be generated by using Bessel gratings to modulate the amplitude and phase of a Bessel beam is proposed.
7 citations
Patent•
19 Jun 2014
TL;DR: In this paper, a bessel beam forming lens consisting of an incidence surface and a light emission surface was proposed. But the beam size of the lens was not specified. But it was shown that the beam length was larger than the thickness of the substrate to be cut.
Abstract: The present invention relates to a bessel beam forming lens comprising an incidence surface and a light emission surface. Laser beams having gaussian-shaped energy intensity distribution are entered into the incidence surface. The light emission surface forms the entered laser beams to bessel beams having a longer length than the thickness of a substrate to be cut. The light emission surface has a conical shape protruding along the progress direction of the laser beams. Also, the light emission surface comprises a first convex part arranged at the center of the light emission surface and protruding in the progress direction of the laser beams; a second convex part arranged in the edge of the light emission surface and protruding in the progress direction of the laser beams; and a concave part arranged between the first and second convex parts and recessed against the progress direction of the laser beams. Some of the laser beams emitted via the concave part are distributed to a section where the laser beams emitted via the first and second convex parts are irradiated into the substrate.
6 citations