Bessel beam

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

Object inspection apparatus using terahertz wave bessel beam

Abstract: The present invention provides an object inspection device having high inspection resolution via a non-destructive method using a light source in the range of terahertz waves and having an operation distance elongated by a long depth of focus. The object inspection device using a terahertz wave Bessel beam according to the present invention comprises: a terahertz wave supply part for generating and supplying terahertz waves; a collimating part for making the terahertz waves supplied by the terahertz wave supply part parallel; a Bessel beam forming part for forming a terahertz wave Bessel beam on at least part of an object to be inspected by using the terahertz waves made parallel by the collimating part; a light collecting part for collecting the terahertz waves scattered after penetrating the object to be inspected; and a terahertz wave detecting part for collecting and detecting the terahertz waves collected by the light collecting part.

Diffraction of Bessel beams on 2D amplitude gratings -- a new branch in the Talbot effect study.

Abstract: In this paper, an analytical theory for the diffraction of a Bessel beam of arbitrary order $J_l(\kappa r)$ on a 2D amplitude grating is presented. The diffraction pattern in the main and fractional Talbot planes under certain conditions is a lattice of annular microbeams, the diameters of which depend on the grating period, the illuminating beam diameter, the number of the Talbot plane, and the topological charge $l$. For the rings near the optical axis, the latter reproduces $l$ of the illuminating beam. Experiments carried out on the Novosibirsk free electron laser at a wavelength $\lambda = 141$$\mu$m using gratings with hole diameters of down to $d \approx 2\lambda $, as well as, the numerical simulations, well support the theory. Since the Laguerre-Gaussian beams can be represented as a superposition of Bessel beams, results of this paper can be applied to the analysis of the Talbot effect with the Laguerre-Gaussian beams.

Nano-thin 2D axicon generating nondiffracting surface waves

Abstract: We investigate nondiffracting surface waves. On top of the Bloch surface wave platform, a 60-nm-thick TiO 2 isosceles triangle serves as a 2D axicon. Scanning near-field microscopy measurements verify nondiffracting surface beam properties.

Nanostructuring of ITO thin films through femtosecond laser ablation

Abstract: Due to reduced thermal effects, tightly focused femtosecond laser beams can yield submicron resolution with minimal side effects. In laser direct writing applications, diffraction-free nature of the Bessel beams relaxes alignment of the sample and shortens the production time. Micron-sized central spots and long depth of focused beams can be simultaneously produced. We apply fs Bessel beam single-pulse ablation method to transparent conductive oxide films. We use laser of 1030 nm wavelength and two different axicons (base angles are 25° and 40°). Fabricated structures are characterized by optical microscope, atomic force microscope and scanning electron microscope. Laser beam shaping and virtues of non-diffracted Bessel beams provide periodic structures for scribing in the solar cells or high-resolution displays and reduce the process time.