Bessel beam

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

Three-level filter for increased depth of focus and Bessel beam generation

Abstract: A novel axially-symmetric filter for increasing focal depth and generating an approximation to a Bessel beam is proposed. It consists of an array of rings of strength –1,0 and 1. The design is based on an analytic solution, and combines high resolution in the transverse direction with good efficiency. One presented design increases the depth of focus compared with a standard lens by more than 30 times, with a very flat axial intensity distribution over this range. Effects of discretization are discussed. Various different approaches to increasing depth of focus are compared, to put the new design into perspective.

Bessel beam interferometer and measurement method

Abstract: A measurement method and apparatus rely upon the coherent optical interference between a reference beam and a diffractionless sensing beam having an optical path length that has been disturbed. The interference pattern can be analyzed to determine a measurement parameter of the disturbance. The diffractionless beam is particularly a Bessel beam. Exemplary optical interferometer types including Mach-Zehnder, Michelson, Sagnac and Fabry-Perot include a Bessel beam generator to generate a diffractionless beam as the sensing optical beam and in some aspects the reference optical beam of the interferometer. The sensing optical beam propagates along a sensing optical beam path in free-space. The reference optical beam path may be a free-space medium or a material medium such as an optical fiber. The sensing optical beam path is subject to a disturbance manifested by the optical interference pattern between the sensing optical beam and the reference optical beam. Parameters of the disturbance, such as motion, acoustics, environmental conditions and others can be determined by analysis of the interference pattern.

Multifocal spectral-domain optical coherence tomography based on Bessel beam for extended imaging depth

Abstract: To advance the practical application of optical coherence tomography (OCT) in the field of biomedical imaging, the imaging depth must be extended without sacrificing resolution while maintaining sufficient sensitivity. However, there is an inherent trade-off between lateral resolution and depth of field (DOF) in OCT. To address this shortcoming, this article proposes a multifocal Bessel beam spectral-domain optical coherence tomography (MBSDOCT) capable of increasing the DOF with unchanged lateral resolution and a high signal-to-noise ratio. The proposed technique is demonstrated by simulation and experiment. A three-focal MBSDOCT with an axicon lens theoretically achieved a DOF of ∼6 mm with a lateral resolution of ∼13 μm. In imaging experiments performed on the acinar cells of orange tissue, a measured DOF of ∼4 mm was demonstrated with a sensitivity penalty of ∼18.1 dB, relative to the Gaussian beam spectral-domain OCT, with a 9-mW light source.

The Generation of Bessel Beam and Its Application in Millimeter Wave Imaging

Abstract: In this paper, the zero-order Bessel beam at W band is generated by using a diagonal horn, a convex lens, and an axicon. The generated Bessel beam has a beam spot size of 5.5mm and can propagate with a distance longer than 100mm. Several imaging experiments with the generated zero-order Bessel beam are done. The results show that the millimeter wave imaging system with the generated Bessel beam can be used to detect object as small as 1mm.