Bessel beam

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

Ablation enhancement of fused silica glass by femtosecond laser double-pulse Bessel beam

Abstract: In this study, the double-pulse Bessel beam ablation of fused silica glass is investigated. Compared to a conventional Bessel–Gauss beam, a double-pulse Bessel–Gauss beam can greatly enhance the photo-modification zone. As the time delay increases, the photo-modification zone first increases and then decreases. By optimizing the processing parameter, the photo-modification zone with a diameter in the range of 1.5–3 µm and an aspect ratio of about 1500:1 can be fabricated. Compared to the zone processed by a single-pulse Bessel–Gauss beam, the photo-modification zone of a double-pulse Bessel–Gauss beam increases by a factor of 500. Furthermore, the processing parameter of the pulse energy distribution ratio is also investigated to optimize fabrication. In addition, the experimental results show that the obtained etching rate of the photo-modification zone processed by the double-pulse Bessel–Gauss beam with a time delay of 50 ps is four times that of the single-pulse Bessel–Gauss beam. As an application example, a microreaction cell is fabricated using a femtosecond laser, double-pulse Bessel–Gauss beam to demonstrate the advantage of the proposed method in fabricating three-dimensional microfunctional structures.

Variance of fluctuations of the orbital angular momentum of Bessel beam in turbulent atmosphere

Abstract: In this article, the theoretical researches of variance of fluctuations of the orbital angular momentum of the Bessel optical beam propagating in turbulent atmosphere have been developed. The variance of fluctuations of Bessel-Gaussian beam on beam parameters: a transverse wave number of optical radiation, a Fresnel number of the transmitting aperture and a topological charge are in details analyzed. It is shown that a variance of fluctuations of the orbital angular momentum of a vortex Bessel-Gaussian beam during propagation in turbulent atmosphere it is essential less than the similar characteristic of a Laguerre-Gaussian beam.

Shaped beam scattering by an anisotropic particle

Abstract: An exact semi-analytical solution to the electromagnetic scattering from an optically anisotropic particle illuminated by an arbitrarily shaped beam is proposed. The scattered fields and fields within the anisotropic particle are expanded in terms of spherical vector wave functions. The unknown expansion coefficients are determined by using the boundary conditions and the method of moments scheme. For incidence of a Gaussian beam, zero-order Bessel beam and Hertzian electric dipole radiation, numerical results of the normalized differential scattering cross section are given to a uniaxial, gyrotropic anisotropic spheroid and circular cylinder of finite length. The scattering properties are analyzed concisely.

Two-photon fluorescence stereomicroscopy with bessel beams

Abstract: Three dimensional distributions of cells can be usually acquired by optical sectioning methods, such as multiphoton excitation and confocal fluorescence laser scanning microscopy. Though the lateral scan rates can reach up to several kHz, the relatively slow axial scan comprises the speed of real-time imaging of a volume. Here we propose a three dimensional imaging method that uses Bessel beams as excitation in multiphoton fluorescence microscopy. The extended focus of the Bessel beam allows recording a volume of cells without scanning the depth. The depth information can be retrieved by recording a pair of parallax views of the same volume. We have demonstrated the stereoscope capability on a homebuilt two-photon fluorescence microscope.