Bessel beam

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

Method for menufacturing a photonic device using optical fibers, photonic device using optical fibers and optical tweezer

Abstract: PURPOSE: An optical element manufacturing method using optical fiber and non-refractive bessel beam, and an optical tweezer using the same are provided to increase the forming distance of non-refractive bessel beam. CONSTITUTION: A hollow optical fiber(120) connects one end to a single mode optical fiber(110). A coreless optical fiber(130) connects one end to the holey optical fiber without core. A polymer lens(140) is formed on a cross section of the other group end of the optical fiber without core.

Optimization of the Input Fundamental Beam by Using a Spatial Filter Consisting of Two Apertures

Abstract: Second harmonic generation (SHG) is widely used in nonlinear optical spectroscopy. The optimization of the power efficiency of SHG is of primary importance in a number of applications, especially when continuous wave (cw) beams with relatively low peak power are frequency doubled. If the input light field is a Gaussian beam, the dynamics of SHG is determined by the power of the input beam, the spatial shape of the input beam, its confocal parameter, the Poynting vector walk-off length, the phase matching condition, and so on [1,2]. The existence of an optimum for the beam waist is the result of the best compromise between the beam focalization, which tends to increase the efficiency, and the diffractive spread, which tends to reduce the efficiency. In some previous paper, a Bessel beam could generate the second harmonic more efficiently than Gaussian beams because they propagate without any modification of the transverse intensity profile and, in this respect, they are ‘non-diffracting’ [3–5] . Beam shaping is a process whereby the irradiance of the laser beam is changed along its cross section. In order for beam shaping to be effective, it is necessary to be able to measure the degree to which the irradiance pattern or beam profile has been modified by the shaping medium.

Multi-core fiber Bessel beam array optical tweezers

Abstract: The invention discloses multi-core fiber Bessel beam array optical tweezers, and belongs to the technical field of optical capturing. The optical tweezers comprise a multi-core fiber, a phase step multi-mode fiber and a laser light source. The tail fiber of the laser light source is in fused biconical taper coupling connection with one end of the multi-core fiber, and the other end of the multi-core fiber is in conventional coaxial fused connection with one end of the phase step multi-mode fiber. The other end of the phase step multi-mode fiber is fused to form an approximately semicircular structure with the radius R. The optical tweezers provided by the invention can be used for the batch operation and screening of a plurality of miniature particles, and achieves the three-dimensional array arrangement of specific positions. The optical tweezers can achieve the changing of an optical trap and the number of the captured particles through the adjustment of the number of cores of the multi-core fiber, the length of the phase step multi-mode fiber and the fused biconical taper shape of one end of the phase step multi-mode fiber, achieves the microscopic fine operation of the miniature particles, and has a high application value in the biomedical research field.

Fabrication of Weighted Conical Transducer for Generation of Quasi-Nondiffracting Beam.

Abstract: The use of conical transducers with weighted velocity distribution has been proposed by the authors as a simple and practical approach for generating Bessel-type quasi-nondiffracting beams. In this paper we present the fabrication of a weighted conical transducer employing a dielectric layer of varying thickness. The dielectric layer is used for applying a radially diminishing voltage to the piezoelectric material, which will create the desired weighting on the vibration amplitude. It is shown from the experiments that the weighted conical transducer has the capability of generating a narrow-beam ultrasound over a long range along the central axis.

Imaging in thick samples, a phased Monte Carlo radiation transfer algorithm.

Abstract: Significance: Optical microscopy is characterized by the ability to get high resolution, below 1 μm, high contrast, functional and quantitative images. The use of shaped illumination, such as with lightsheet microscopy, has led to greater three-dimensional isotropic resolution with low phototoxicity. However, in most complex samples and tissues, optical imaging is limited by scattering. Many solutions to this issue have been proposed, from using passive approaches such as Bessel beam illumination to active methods incorporating aberration correction, but making fair comparisons between different approaches has proven to be challenging. Aim: We present a phase-encoded Monte Carlo radiation transfer algorithm (φMC) capable of comparing the merits of different illumination strategies or predicting the performance of an individual approach. Approach: We show that φMC is capable of modeling interference phenomena such as Gaussian or Bessel beams and compare the model with experiment. Results: Using this verified model, we show that, for a sample with homogeneously distributed scatterers, there is no inherent advantage to illuminating a sample with a conical wave (Bessel beam) instead of a spherical wave (Gaussian beam), except for maintaining a greater depth of focus. Conclusion: φMC is adaptable to any illumination geometry, sample property, or beam type (such as fractal or layered scatterer distribution) and as such provides a powerful predictive tool for optical imaging in thick samples.