Bessel-like Beams Research Articles

Optical Bessel-like Beams with Engineered Axial Phase and Intensity Dis-tribution

Optical Bessel-like Beams with Engineered Axial Phase and Intensity Dis-tribution

Polarization Controllable Device for Simultaneous Generation of Surface Plasmon Polariton Bessel-Like Beams and Bottle Beams.

Realizing multiple beam shaping functionalities in a single plasmonic device is crucial for photonic integration. Both plasmonic Bessel-like beams and bottle beams have potential applications in nanophotonics, particularly in plasmonic based circuits, near field optical trapping, and micro manipulation. Thus, it is very interesting to find new approaches for simultaneous generation of surface plasmon polariton Bessel-like beams and bottle beams in a single photonic device. Two types of polarization-dependent devices, which consist of arrays of spatially distributed sub-wavelength rectangular slits, are designed. The array of slits are specially arranged to construct an X-shaped or an IXI-shaped array, namely X-shaped device and IXI-shaped devices, respectively. Under illumination of circularly polarized light, plasmonic zero-order and first-order Bessel-like beams can be simultaneously generated on both sides of X-shaped devices. Plasmonic Bessel-like beam and bottle beam can be simultaneously generated on both sides of IXI-shaped devices. By changing the handedness of circularly polarized light, for both X-shaped and IXI-shaped devices, the positions of the generated plasmonic beams on either side of device can be dynamically interchanged.

Reynolds number and diffusion coefficient of micro- and nano-aerosols in optical pipelines

In this study, the microscopic particle motion inside an optical pipeline, such as particle motion through a mechanical tube, is investigated. The photons in an optical tube guide the particles towards the center of the light beam by inducing photophoretic and radiation pressure forces. Laguerre–Gaussian- and Bessel-like beams are examples of such optical tubes. The Reynolds number of particle motion in optical tubes is investigated. The power of the light beam and the ratio of the particle radius to the light beam ring radius influence the turbulence of the particle flow and the value of the Reynolds number. The diffusion coefficient of particle movement in such pipelines is derived, which indicates that an optical tube is a good tool for guiding and trapping particles in micron- and nanometer-scale dimensions.

Thermoacoustic-reflected focusing lens based on acoustic Bessel-like beam with phase manipulation**Project supported by the National Natural Science Foundation of China (Grant Nos. 11774137 and 51779107), the Six-Talent Peaks Project in Jiangsu Province, China (Grant No. GDZB-019), the China Postdoctoral Science Foundation (Grant No. 2017M621643), the Natural Science Foundation of Jiangsu Higher Educational Institutions of China (Grant No. 18KJB140003), and the

We report the realization of broadband reflected acoustic focusing lenses based on thermoacoustic phased arrays of Bessel-like beams, in which the units of phase manipulation are composed of three rigid insulated boundaries and a thermal insulation film in air with different temperatures. Based on these units, we realize a reflected focusing lens which can focus reflected acoustic energy on a line, and its fractional bandwidth can reach about 0.29. In addition, we discuss the influences of the base angle of Bessel-like beam, the number of basic unit, and the variation of unit temperature on focusing performances in details. Furthermore, the reflected focusing lens for the cylindrical acoustic wave based on the Bessel-like beam is also demonstrated. The proposed focusing lens has the advantages of a broad working bandwidth, large focus size, and high robustness, which may provide possibilities for the design and application of acoustic lenses.

Combined half-integer Bessel-like beams: A set of solutions of the wave equation

We report a family of solutions of the homogeneous free-space scalar wave equation. These solutions are determined by linear combinations of the half-integer order Bessel functions. We call these beams ``combined half-integer Bessel-like beams.'' It is shown that, by selecting suitable combinations of the half-integer order Bessel functions, a wide set of beams can be produced in which they may carry the orbital angular momentum (OAM) or not. We show that this family of beams satisfies a ``radial structured'' boundary condition at $z=0$ plane, therefore they can be produced by the diffraction of a plane wave from suitable ``radial structures.'' Some specific examples of the half-integer Bessel-like beams are introduced. Especially, a set of spatially asymmetric beams, having half-integer OAM, is introduced that can be used to make the concentration of the absorbing and dielectric micro- or nanoparticles in a microsolution inhomogeneous. Also, by manipulating the Fourier series of the radial structures, three subfamily of beams can be produced including the radial carpet, petallike, and ringlike vortex beams. The intensity profile of the petallike beams forms two dimensional optical latices with polar symmetry at the transverse plane. The ringlike vortex beams carry OAM. Here, by solving the wave equation we present the full image of the radial carpet beams. All the presented beams have nondiffracting, accelerating, and self-healing features. The combined half-integer Bessel-like beams can be considered in other areas of wave phenomena, ranging from sound and elastic waves to many other kinds of classical waves. Therefore, this work has profound implications in many linear wave systems in nature.

Erratum: “Deep imaging in highly scattering media by combining reflection matrix measurement with Bessel-like beam based optical coherence tomography” [Appl. Phys. Lett. 113, 011106 (2018)

Erratum: “Deep imaging in highly scattering media by combining reflection matrix measurement with Bessel-like beam based optical coherence tomography” [Appl. Phys. Lett. <b>113</b>, 011106 (2018)

Non-diffraction-length, tunable, Bessel-like beams generation by spatially shaping a femtosecond laser beam for high-aspect-ratio micro-hole drilling.

Bessel beams are advantageous in high aspect-ratio microhole drilling because of their immunity to diffraction. However, conventional methods of generating Bessel beams result in poor adjustability of the nondiffraction length. In this study, we theoretically describe and experimentally demonstrate the generation of Bessel-like beams (BLBs) with an adjustable nondiffraction length by using a phase-only spatial light modulator. In this method, nondiffraction lengths varying from 10 to 35 mm can be achieved by changing the designed phase profile (curvature). High-quality, high aspect ratio (560:1) and length-adjustable microholes can be drilled by spatially shaping a femtosecond laser beam.

Coherence of a Bessel beam and a conic wave in turbulent atmosphere

Coherent properties of diffraction-free Bessel-like optical beams propagating in the turbulent atmosphere are theoretically studied. An analytical solution of the equation for the second-order transverse function of mutual coherence of the optical radiation field, which was obtained from paraxial approximation of the scalar wave equation, is analyzed. The behavior of the degree of coherence, coherence radius, and integral scale of the degree of coherence of the Bessel–Gaussian beam and conic wave obtained through conic focusing of a Gaussian beam by an axicon is analyzed for different beam parameters and characteristics of the turbulent atmosphere. Significant qualitative and quantitative differences are discovered between the studied coherence characteristics of the Bessel–Gaussian beam and the conic wave. In general, under identical propagation conditions in the turbulent atmosphere, the coherence of the conic wave is higher than that of the Bessel–Gaussian beam. The comparison of two spatial scales of the degree of coherence of optical beams reveals that the integral scale for diffraction-free beams is a more representative characteristic than the coherence radius. The integral scale of the degree of coherence of diffraction-free beams is more unequivocally connected with the conditions of propagation of optical radiation in the turbulent atmosphere.

Bessel-like beam generated by an axicon based on parallel-plate waveguides.

The axicon is the simplest and most effective optical element for generating the zero-order Bessel-like beam. The zero-order Bessel-like beam, which has the characteristics of small spot size, high brightness, good direction, and large collimation distance, can be applied to optical micromanipulation and power transmission. In this paper, we proposed and designed a structure for phase manipulation based on parallel-plate waveguides that can be used to realize the functionality of the axicon in the terahertz (THz) region. Meanwhile, we characterized the influence of the cone angle of the axicon and the waist radius of the incident Gaussian beam on the generated zero-order Bessel-like beam by simulation. The planar structure, consisting of a parallel stack of thin copper plates, can be easily fabricated to fulfill the phase requirement to realize the zero-order Bessel-like beam and also can be utilized in THz imaging systems, THz sensing systems, THz communication systems, etc.

Deep imaging in highly scattering media by combining reflection matrix measurement with Bessel-like beam based optical coherence tomography.

Multiple scattering in biomedical tissue limits the imaging depth within a range of 1-2 mm for conventional optical imaging techniques. To extend the imaging depth into the scattering medium, a computational method based on the reflection matrix measurement has been developed to retrieve the singly back-scattered signal light from the dominant detrimental multiple-scattered background. After applying singular value decomposition on the measured matrix in the post-process, the target image underneath the turbid media is clearly recovered. To increase the depth of focus of the incident light by elongating the focal spot along the optical axis, a digital grating pattern is specially designed and displayed on a phase-only spatial light modulator to generate the Bessel-like beam for lateral point scanning. According to the results, the depth of focus is increased up to 2.4 mm which is much longer than the value of ∼50 μm obtained by using the conventional focused Gaussian beam, leading to a deeper penetration depth due to the self-healing feature of the Bessel-like beam. In addition, generation of the Bessel-like beam simplifies the axial scanning process by getting rid of the need to mechanically translate the focal zone along the optical axis of an objective with a high numerical aperture. By combining this method with an optical coherence tomography system with a low coherence light source, a depth-resolved optical image is obtained underneath a highly turbid medium.

High-quality tailored-edge cleaving using aberration-corrected Bessel-like beams.

We report on the usage of ultrashort laser pulses in the form of aberration-corrected Bessel-like beams for laser cutting of glass with bevels. Our approach foresees inclining the material's entrance surface with respect to the processing optics. The detailed analysis of phase distortions caused by the beam transition through the tilted glass surface allows precompensating for occurring aberrations using digital holography. We verify theoretical considerations by means of pump-probe microscopy and present high-quality edges in nonstrengthened silicate glass.

Diffraction by a radial phase modulated spiral zone plate of abruptly autofocusing beams generated with multiple Bessel-like beams

In this paper, we present the generation of optical vortices using an abruptly autofocusing beam that is combined from multiple Bessel-like beams, diffracted by a radial phase shift modulated spiral zone plate (RSSZP). The analytical formula for the diffracted wave field amplitude of the produced beam is derived based on the Fresnel diffraction integral formula. The results show that the intensity distributions of the produced output beam in radial direction are determined by the initial beam parameters and the RSSZP parameters, such as shifting parameter and topological charge. The present work gives also the diffraction by a RSSZP of a fundamental Gaussian beam which is deduced as a particular case in this investigation.

Dynamic tailoring of surface plasmon polaritons through incident angle modulation

Dynamic tailoring of the propagating surface plasmon polaritons (SPPs) through incident angle modulation is proposed and numerically demonstrated. The generation and tailoring mechanism of the SPPs are discussed. The relationship formula between the incident angle and the generated SPP wave vector direction is theoretically derived. The correctness of the formula is verified with three different approaches using finite difference time domain method. Using this formula, the generated SPP wave vector direction can be precisely modulated by changing the incident angle. The precise modulation results of two dimensional Bessel-like SPP beam and SPP bottle beam array are given. The results can deepen the understanding of the generation and modulation mechanism of the SPPs.

Polarization-based dynamic manipulation of Bessel-like surface plasmon polaritons beam.

Taking advantage of the phase modulation of surface plasmon polaritons (SPPs) generated by subwavelength slits, we elaborately designed an axicon-shaped slit array to dynamically manipulate the profiles of Bessel-like SPPs beams by changing the polarization of the incident light. As the polarization direction of linearly polarized light changes from horizontal to vertical, the profile of SPPs beam will evolve from the zeroth-order Bessel function to the first-order Bessel function. For circularly polarized light, the geometry Pancharatnam-Berry (PB) phase is introduced and can lead to the transverse shift of the main lobe of SPPs beam. The evolution of the beam profile and the distance of the transverse shift are theoretically illustrated by analyzing the phase distribution of SPPs. The proposed versatile approach suggests charming applications including on-chip communications, polarization-controlled particle manipulation and the design of polarization-based dynamic SPPs devices.

High-performance axicon lenses based on high-contrast, multilayer gratings

Axicon lenses are versatile optical elements that can convert Gaussian beams to Bessel-like beams. In this letter, we demonstrate that axicons operating with high efficiencies and at large angles can be produced using high-contrast, multilayer gratings made from silicon. Efficient beam deflection of incident monochromatic light is enabled by higher-order optical modes in the silicon structure. Compared to diffractive devices made from low-contrast materials such as silicon dioxide, our multilayer devices have a relatively low spatial profile, reducing shadowing effects and enabling high efficiencies at large deflection angles. In addition, the feature sizes of these structures are relatively large, making the fabrication of near-infrared devices accessible with conventional optical lithography. Experimental lenses with deflection angles as large as 40° display field profiles that agree well with theory. Our concept can be used to design optical elements that produce higher-order Bessel-like beams, and the combination of high-contrast materials with multilayer architectures will more generally enable new classes of diffractive photonic structures.

中心主瓣尺寸可精细调控的类贝塞尔光束

中心主瓣尺寸可精细调控的类贝塞尔光束

Bessel beam asymmetry control for glass dicing applications

Controllable fracture propagation in glass can be obtained by locally weakening the material. The high aspect ratio laser-induced modifications, required for thick glass dicing, can be obtained by use of Bessel-like beams, which have a long non-diffractive length with a small quasi-propagation-invariant central core. We demonstrate the possibility to form elongated modifications in glass with dominant transverse crack propagation direction using axicon-generated asymmetrical Bessel beam. Furthermore, the axicon tilt operation is introduced to add additional astigmatic aberrations for Bessel beam asymmetry control. Dicing results were compared using symmetrical and asymmetrical axicon-generated Bessel beams.

X-ray refractive parabolic axicon lens

An X-ray parabolic refractive axicon, as novel type of beam-shaping optical element, consisting of a refractive lens with a form of the surface represented as a parabolic cone, is proposed and demonstrated. Under coherent X-ray illumination, the axicon generates Bessel-like beam along the optical axis and ring-shaped beam at the imaging distance. A theoretical analysis of the beams formation by the axicons was carried out and corresponding computer simulations were performed. The proposed parabolic axicon was experimentally tested at ID06 ESRF beamline in the X-ray energy range from 10 to 15 keV. Experimentally recorded images of shaped beams are in a good agreement with computer calculations. Future possible applications of the axicon are discussed.

Generation of square arrays of curved Bessel-like beams using continuous-phase encoding gratings

We propose a scheme based on a type of continuous-phase encoding grating for the generation of multiple curved Bessel-like beams simultaneously. It is shown that multiple identical curved Bessel-like beams that diverge from a common center can be generated by overlapping a specially designed phase with a continuous-phase grating, and multiple high-order curved Bessel-like beams can be generated when another spiral phase is embedded. As an example, a 5 x 5 symmetric continuous-phase grating embedded with the special designed phase and a spiral phase is demonstrated based on a spatial light modulator. The experimental results show that 5 x 5 square arrays of bright- and dark-center curved Bessel-like beams were well generated. The proposed method provides an interesting method for obtaining simultaneously multiple curved Bessel-like beams, which should be of high interest for its promising applications in parallel optical manipulation, optical guiding, laser machining or laser surgery, particle acceleration, etc.

Demonstration of Bessel-like beam with variable parameters generated using cross-phase modulation.

We propose a new method to generate Bessel-like beam using cross-phase modulation. The hot rubidium atomic sample is shown to have the ability to vary a Gaussian beam (probe beam) into a Bessel-like beam when the sample is illuminated with a counter-propagating Gaussian beam (pump beam) tuned close to the atomic resonances. It is demonstrated that the Bessel-like beam exhibits self-healing after encountering an obstruction on the beam path. The parameters of the Bessel-like beam are found to be easily adjusted by the pump beam power and sample temperature. Moreover, this method is even applicable to the probe beam of low power, having more practical value than the method using self-phase modulation which needs high input beam power. The merits of variable parameter, no requirement for input beam power, simple setup, and low cost would make this method of significance in a variety of applications, especially in those areas where Bessel beam power is needed to be low and parameter to be adjusted easily without changing the setup.