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: Large propagation distance, characteristics of Bessel beam is better suited for in-depth single as well as two-photon optogenetic stimulation of the ChR2 sensitized cells, and theoretical simulations were conducted using Bessel and Gaussian beam, based on Monte Carlo photon transport method applied on layered mouse brain geometry.
6 citations
TL;DR: In this article, the authors developed an algorithm for modeling Bessel beam propagation and then compared both beam propagations in two-layered mice brain under variance of multiple variables (i.e., wavelength, numerical aperture, and beam size).
Abstract: Optogenetics technology has opened new landscapes for neuroscience research. Due to its non-diffracting and selfhealing
nature, Bessel beam has potential to improve in-depth optogenetic stimulation. A detailed understanding of
Bessel beam propagation, as well as its superiority over commonly used Gaussian beam, is essential for delivery and
control of light irradiation for optogenetics and other light stimulation approaches. We developed an algorithm for
modeling Bessel beam propagation and then compared both beam propagations in two-layered mice brain under variance
of multiple variables (i.e., wavelength, numerical aperture, and beam size). These simulations show that Bessel beam is
significantly advantageous over Gaussian beam for in-depth optogenetic stimulation, leading to development of lessinvasive
probes. While experimental measurements using single-photon Bessel-Gauss beam generated by axicon-tip
fiber did not show improved stimulation-depth, near-infrared Bessel beam generated using free-space optics and an
axicon led to better penetration than near-infrared Gaussian beam.
6 citations
TL;DR: In this article, the spectral properties of spatially coherent polychromatic high order Bessel beams focused by an aperture lens are studied, and it is shown that the spectrum in the neighborhood of focus is proportional to the spectrum at the aperture and a spectral modifier.
6 citations
TL;DR: In this paper, high quality Bessel beams with adjustable cone angles are realized using a unimorph deformable mirror (DM) with 61 actuators, which not only generates an adjustable diverging or converging conical mirror surface in high precision, but also corrects the optical aberrations in the optical system.
Abstract: High-quality Bessel beams with adjustable cone angles are realized using a unimorph deformable mirror (DM) with 61 actuators. The DM not only generates an adjustable diverging or converging conical mirror surface in high precision, but also corrects the optical aberrations in the optical system. Furthermore, the annular beams are generated via the Fourier transform of the generated Bessel beams. The core size of the Bessel beam and the radius of the annular beam are proved to be flexibly controlled by the DM without changing the optical elements and realigning the optical path. Since the unimorph DM has a very high damage threshold, the proposed method paves the way for potential applications involving high-power lasers.
6 citations
TL;DR: In this paper, high-throughput, taper-free TSVs fabrication using femtosecond Bessel beams operated at different wavelengths from 400 nm to 2.4 μm is presented.
Abstract: For higher-density integration and acceleration of operating speed in Si ICs, 3D integration of wafers and/or dies is essential. Fabrication of current 3D ICs relies on 3D assembly which electrically connects stacked chips to form a single circuit. A key technology for the 3D assembly is TSVs which are vertical electrical connections passing completely through silicon chips to electrically connect vertically assembled Si ICs. Typical TSVs have wide features, with diameters of a range from several microns to 50 μm and depths up to 500 μm with aspect ratios up to 15 depending on the application and integration scheme. In this work, we present high-throughput, taper-free TSVs fabrication using femtosecond Bessel beams operated at different wavelengths from 400 nm to 2.4 μm. Furthermore, special phase filters are designed to suppress the damages induced by the side-lobes of Bessel beams for high-quality TSVs fabrication. Our technique can be potentially used for 3D assembly in manufacture of 3D silicon integrated circuits.
6 citations