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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: In this paper, the singularities of the Poynting vector were studied, at which the energy flux density turns to zero, and the existence conditions and positions of singularities were revealed, which are located at cylindrical surfaces around the beam axis.
Abstract: For propagating and evanescent vector Bessel beams, we study the singularities of the Poynting vector (Poynting singularities), at which the energy flux density turns to zero. Poynting singularities include all the phase singularities and some of polarization ones (L- and C-points). We reveal the existence conditions and positions of singularities, which are located at cylindrical surfaces around the beam axis. We mark the special case of the evanescent Bessel beam in the form of cylindrical standing wave, that is singular at any spatial point.
3 citations
02 May 2011
TL;DR: In this paper, an acoustic tweezers consisting of a multi-foci Fresnel lens on 127 µm thick PZT sheet was designed to capture micron-sized particles.
Abstract: This paper describes an acoustic tweezers consisting of a multi-foci Fresnel lens on 127 µm thick PZT sheet, designed to capture micron-sized particles. The multi-foci Fresnel lens was designed to have similar working mechanism as that of an axicon lens to generate an acoustic Bessel beam and, correspondingly, to generate negative axial radiation force capable of trapping one or more microparticle(s). The fabricated acoustic tweezers successfully trapped lipid particles ranging in diameter from 50 to 200 µm and microspheres ranging in diameter from 70 to 90 µm at a distance of 2 to 5 mm from the tweezers without any contact between the transducer and microparticles.
3 citations
TL;DR: In this article, a generalized coupling coefficient between two circular apertures in the Fresnel zone is derived, and the optimal aperture illumination is found numerically by constructing an aperture field from a summation of Bessel beams with different axicon angles.
Abstract: This article investigates wireless power transfer in the Fresnel zone using cylindrical vector beams. First, a generalized coupling coefficient between two circular apertures in the Fresnel zone is derived. From the generalized coupling coefficient, explicit coupling coefficients between two circular (focused or unfocused) apertures supporting Gaussian, Bessel–Gaussian, and Laguerre–Gaussian beams are found in closed form. The analytically derived coupling coefficients and corresponding efficiencies are compared with those obtained through numerical integration of the reaction integral, as well as the results of a commercial electromagnetic solver. Then, it is demonstrated that a finite aperture, which supports a cylindrically apodized Bessel beam, is close to the optimal illumination. Also, it is shown that Bessel beams have a higher coupling coefficient than conventional Gaussian beams. Finally, the optimal aperture illumination is found numerically by constructing an aperture field from a summation of Bessel beams with different axicon angles. That is, the complex amplitude of each Bessel beam is found that maximizes coupling between the two apertures. The optimal illumination radiates a magnetic field equal to the complex conjugate of the receiver aperture’s electric field. This observation agrees with those for optimal illumination in the context of a confocal optical resonator.
3 citations
TL;DR: In this article, a two-dimensional metasurface and catenary structure that enables phase-tuning of electromagnetic waves was proposed. But the catenary was modified to produce a non-diffracting 0th-order Bessel beam with a maximum gain of 15.1 dB.
3 citations