Bessel beam

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

Ultrafast laser micromachining the ultra-low expansion glass-ceramic: Optimization of processing parameters and physical mechanism

Abstract: To fulfill the precise requirements of laser gyroscope for inertial navigation, using the mean surface roughness, taper angle and circularity degree as indicators, we optimize the processing parameters about ultrafast laser micromachining a commercial ultra-low expansion glass-ceramic (ULGC). Furthermore, through careful characterizations, we identify the sequential appearance of photo-darkening, crystalizing, melting, foaming and vaporizing regions during the interactions of ultrafast laser with ULGC. Especially, the foaming region is identified to effectively mediate the thermal stress at the interfaces between different regions. Originated from the Gaussian distribution of energy, poor processing quality by a Gaussian beam is mainly ascribed to the formation of various regions. By using a Bessel beam, higher surface quality could be obtained due to the possibility of the occurrence of only a foaming region in irradiated regions. This discovery gives us an important clue to optimize processing parameters to obtain high-quality ultrafast laser micromachining surface.

Spatial and spectral properties of stimulated Rayleigh-wing scattering pumped with a Bessel beam: role of four-photon parametric processes

Abstract: Stimulated Rayleigh-wing scattering is studied here in various liquids excited with a Bessel beam that allows a complete spatial separation between the transmitted exciting light and the scattered light. The results show that a large Stokes spectral band displaying substructures is obtained in the absence of self-focusing, cross-focusing, self-phase modulation, and cross-phase modulation. An interpretation is proposed based on the role of cascade Stokes–anti-Stokes coupled scattering processes.

Fast, 3D imaging via confocal line scanning of a Bessel beam using a single galvo mirror

Abstract: We developed a light-sheet illumination microscope that can perform fast 3D imaging of transparent biological samples. The light-sheet is created by raster scanning of a Bessel Beam with one galvo-mirror. Fluorescence excited from the thin layer of the sample is de-scanned by the same galvo-mirror, and then spatially filtered by a slit so that out-of-focus fluorescence generated by the side lobes of the Bessel beam is rejected. The spatially filtered fluorescence is returned by a series of optics and is re-scanned by the same galvo-mirror across the chip of a camera such that the fluorescence image is constructed in real-time. Compared to two-photon Bessel beam excitation or other confocal line scanning approaches, our method is of lower cost, simpler, and doesn’t require calibration and synchronization of multiple galvo mirrors. We demonstrated the capability of fast 3D imaging and background rejection capabilities of this microscope with fluorescent beads embedded in PDMS.

Analytic description of nonideal Bessel beam propagation

Abstract: Since the experimental demonstration in 1987, Bessel Beams have attracted much attention because of their main features to resist diffractive effects over distances exceeding the usual diffraction length of gaussian beams. Despite that fact, to the best of our knowledge, the study of Bessel Beam's propagation has no closed analytic form and it often leads to the numerical evaluation of diffraction integrals, which can be very awkward. Based on Schrodinger equation of quantum mechanics and adequate choice of basis function in a Hilbert space, we introduce a new technique able to expand the optical wave field in a series, allowing to obtain analytic expressions for the propagation of any given initial field distribution. To demonstrate the robustness of the method two cases were taken into account: gaussian and zeroth-order Bessel beam propagation.