Showing papers on "Bessel beam published in 2009"
TL;DR: This paper presents a technique to generate Bessel beams with a tunable axial intensity within the accessible range of spatial frequencies and demonstrates how one can form a Bessel beam with a varying propagation constant along its axial extent which results in a Tunable scaling of its lateral cross-section.
Abstract: Due to their immunity to diffraction, Bessel light modes potentially offer advantages in various applications. However, they do exhibit significant intensity variations along their axial propagation length which hampers their applicability. In this paper we present a technique to generate Bessel beams with a tunable axial intensity within the accessible range of spatial frequencies. The beam may be engineered to have a constant intensity along its propagation length. Finally, we demonstrate how one can form a Bessel beam with a varying propagation constant along its axial extent which results in a tunable scaling of its lateral cross-section.
153 citations
TL;DR: The interference of surface plasmon waves excited by a radially polarized beam creates an evanescent Bessel beam with enhanced localized field and spot size beyond the diffraction limit.
Abstract: We report the experimental confirmation of the evanescent Bessel beam generation via surface plamson resonance excitation with a radially polarized beam. The interference of surface plasmon waves excited by a radially polarized beam creates an evanescent Bessel beam with enhanced localized field and spot size beyond the diffraction limit. The excitation of the surface plasmon is confirmed by the observation of a narrow dark ring at the back focal plane. Two-dimensional intensity distributions at different distances from the sample surface are mapped by a collection-mode near-field scanning optical microscope to verify the nondiffracting and decaying natures of the evanescent Bessel beam.
141 citations
TL;DR: The partial-wave series for the scattering of an acoustic helicoidal Bessel beam by a sphere centered on the axis of the beam is applied to the calculation of the acoustic radiation force by the beam on the sphere in an inviscid fluid.
Abstract: The partial-wave series for the scattering of an acoustic helicoidal Bessel beam by a sphere centered on the axis of the beam is applied to the calculation of the acoustic radiation force by the beam on the sphere in an inviscid fluid. The term “helicoidal” refers to a type of beam having an axial amplitude null and an azimuthal phase gradient. Such a beam is known as an acoustic vortex and only the case of a vortex having a unit magnitude topological charge is considered. There is no monopole contribution to the radiation force. Radiation force examples are computed for a soft sphere, a fixed rigid sphere, a movable rigid sphere, an aluminum sphere in water, and an acrylic sphere in water. Beam parameters are found for the rigid sphere and the aluminum and acrylic cases in which the radiation force is directed opposite the propagation direction of the beam. Negative radiation forces appear to be associated with relatively weak scattering into the backward hemisphere. Some aspects of the low frequency scattering of plane waves and helicoidal Bessel beams are examined for movable rigid spheres.
119 citations
TL;DR: In this article, an analytical solution for the scattering of an acoustic Bessel beam of any order by a deformable sphere centered on the beam is used to calculate the acoustic radiation force acting along the wave propagation axis.
Abstract: An analytical solution for the scattering of an acoustic Bessel beam of any order by a deformable sphere centered on the beam is used to calculate the acoustic radiation force acting along the wave propagation axis. Situations are noted where, even in the absence of absorption, the radiation force of a high-order Bessel beam acting on the sphere is opposite to the direction of beam propagation. In the present research, the cases of a fluid and solid elastic spheres are considered with particular emphasis on how the mechanical properties and resonances of spheres as well as the beam parameters affect the negative radiation force. Conditions for the negative attracting force on hexane (fluid), aluminum and gold spheres are established, which help in designing acoustic tweezers operating with high-order Bessel beams of progressive waves for potential applications in particle entrapment and manipulation.
109 citations
TL;DR: The use of Bessel beams significantly reduces constraints on critical sample positioning in the nanoscale writing regime, enabling the use of femtosecond pulses for fast inscription of nanometer-scale features over large sample areas.
Abstract: We demonstrate the application of nondiffracting Bessel beams for reproducible nanometric-scale feature patterning in glass. A femtosecond pulse zero-order Bessel beam with a central spot radius of 360 nm was used to write 500 nm radius nanocraters over a longitudinal positioning range exceeding 20 μm, with a variation in radius of less than 10%. The use of Bessel beams significantly reduces constraints on critical sample positioning in the nanoscale writing regime, enabling the use of femtosecond pulses for fast inscription of nanometer-scale features over large sample areas.
102 citations
TL;DR: In this article, the authors present direct measurements of the spatiotemporal electric field of an ultrashort Bessel-X pulse generated using a conical lens (axicon).
Abstract: We present direct measurements of the spatiotemporal electric field of an ultrashort Bessel-X pulse generated using a conical lens (axicon). These measurements were made using the linear-optical interferometric technique SEA TADPOLE, which has micrometer spatial resolution and femtosecond temporal resolution. From our measurements, both the superluminal velocity of the Bessel pulse and the propagation invariance of the central spot are apparent. We verified our measurements with simulations.
92 citations
TL;DR: The acoustic radiation force of Langevin type resulting from the interaction of a high-order Bessel beam with a rigid immovable sphere in an ideal fluid is theoretically investigated and a negative radiation force caused by the Lagrangean energy density is found.
Abstract: The acoustic radiation force of Langevin type resulting from the interaction of a high-order Bessel beam with a rigid immovable sphere in an ideal fluid is theoretically investigated. The analysis is based on applying the generalized Rayleigh series used in the near-field acoustic scattering problem to calculate the force. With appropriate selection of specific Bessel beam parameters, results for the rigid sphere unexpectedly reveal a negative radiation force caused by the Lagrangean energy density. Specifically, the negative force on the rigid sphere arises when the kinematic energy density is larger than the potential energy density. This condition provides an impetus for further designing acoustic tweezers operating with high-order Bessel beams of progressive waves for potential applications in particle entrapment and manipulation.
85 citations
TL;DR: The manipulation of a Gaussian laser beam using conical diffraction in a high optical quality biaxial crystal of KGd(WO(4))(2) has been examined in detail with emphasis on the experimental techniques involved and intuitive explanations of the notable features.
Abstract: The manipulation of a Gaussian laser beam using conical diffraction in a high optical quality biaxial crystal of KGd(WO4)2 has been examined in detail with emphasis on the experimental techniques involved and intuitive explanations of the notable features. Two different optical arrangements were used to form the Pogendorff double-ring light pattern in the focal image plane. The formation of both diverging and non-diverging zeroth and first order Bessel beams was investigated. The various intensity distributions and polarization properties were measured and compared with the predictions of well-established theory.
81 citations
TL;DR: The question that is addressed concerns the possibility of creating a zeroth-order Bessel-like beam that spirals around the axis of propagation and approximations to such a light field can be experimentally realized by using an axicon and a hologram.
Abstract: The question that we are addressing concerns the possibility of creating a zeroth-order Bessel-like beam that spirals around the axis of propagation. The analytical features of the beam propagation are studied theoretically. Approximations to such a light field can be experimentally realized by using an axicon and a hologram. The beam potentially can attract interest in microfabrication applications.
66 citations
TL;DR: In this article, a coupled dipole method (CDM) was employed to study theoretically the interaction among several spherical particles placed into two counter-propagating mutually incoherent Bessel beams.
Abstract: We employed a coupled dipole method (CDM) to study theoretically the interaction among several spherical particles placed into two counter-propagating mutually incoherent Bessel beams. This interaction is mediated by the light scattering among the particles. It has already been demonstrated that, if the intensity of the incident beam is sufficiently high, the scattered light is strong enough to self-arrange the objects in the space. Namely, the counter-propagating and incoherent Bessel beams are extremely useful to be employed because the interaction among the particles via the scattered light is not superimposed by other optical forces coming from the radiation pressure of each beam and axial gradients of the beam intensities. Therefore so-called optical binding between the particles is enhanced and leads to several stable configurations of the particles. We studied these stable configurations using the CDM for various properties of the beams and particles and we also compared these theoretical results with the experimental observations.
64 citations
TL;DR: A theoretical perspective of how to extend the point-spread function arithmetic from ideal imaging to realistic imaging including ghost images, which are generated by scattered light and are low-correlated with the ideal image.
Abstract: Scattering of illumination light from a laser is a severe problem especially when imaging in thick media. Although this effect occurs in nearly every imaging process, it can be well perceived and analyzed in configurations where the optical axes for illumination and detection are perpendicular to each other. In this paper I present a theoretical perspective of how to extend the point-spread function arithmetic from ideal imaging to realistic imaging including ghost images. These ghost images are generated by scattered light and are low-correlated with the ideal image. Numerical simulations of the propagation of four different types of illumination beams through a cluster of spheres illustrate the effects of inhomogeneous object illumination. Clear differences between a conventional plane-wave illumination, a static light-sheet, and a laterally scanned Gaussian beam, but also relative to a scanned Bessel beam, can be observed.
TL;DR: In this article, the superluminal and diffraction-free properties of a Bessel beam with a conical mirror were analyzed in the radial and on-axis dimensions and verified that the central peak does not spread over a propagation distance of 73 cm.
Abstract: We experimentally analyze a Bessel beam produced with a conical mirror, paying particular attention to its superluminal and diffraction-free properties. We spatially characterized the beam in the radial and on-axis dimensions and verified that the central peak does not spread over a propagation distance of 73 cm. In addition, we measured the superluminal phase and group velocities of the beam in free space. Both spatial and temporal measurements show good agreement with the theoretical predictions.
TL;DR: The present work extends the analysis of the radiation force to the case of a high-order Bessel beam (HOBB) of positive order m having an angular dependence on the phase phi and derives the general expression for the Radiation force function YJm,st(ka,beta,m)<0), which is the radiationforce per unit characteristic energy density and unit cross-sectional surface.
TL;DR: These results allow Mie scattering calculations to be carried out considerably faster than existing methods, something that is of particular interest for time evolution simulations where large numbers of scattering calculations must be performed.
Abstract: Multipole expansions of Bessel and Gaussian beams, suitable for use in Mie scattering calculations, are derived. These results allow Mie scattering calculations to be carried out considerably faster than existing methods, something that is of particular interest for time evolution simulations where large numbers of scattering calculations must be performed. An analytic result is derived for the Bessel beam that improves on a previously published expression requiring the evaluation of an integral. An analogous expression containing a single integral, similar to existing results quoted, but not derived, in literature, is derived for a Gaussian beam, valid from the paraxial limit all the way to arbitrarily high numerical apertures.
TL;DR: A compact all-fiber Bessel beam generator using hollow optical fiber and coreless silica fiber based on a self-assembled polymer lens is reported, which shows good agreement with the experimental observations.
Abstract: We report a compact all-fiber Bessel beam generator using hollow optical fiber (HOF) and coreless silica fiber based on a self-assembled polymer lens. A nearly diffraction-free Bessel beam pattern was observed with its focused beam diameter of 20 µm maintained over a propagation distance of 550 µm. The generated Bessel beams were experimentally tested under various structural parameters such as the diameters of the HOF and operating wavelengths. A beam propagation method was applied to simulate the proposed device, which shows good agreement with the experimental observations.
TL;DR: In this paper, an array-based laser nanolithography where each probe is a microsphere capable of fabricating 100 nm structures using 355 nm light when self-positioned near a surface by Bessel beam optical trapping is presented.
Abstract: Current demands on optical nanolithography require the ability to rapidly and cost-effectively write arbitrary patterns over large areas with sub-diffraction limit feature sizes. The challenge in accomplishing this with arrays of near-field probes is maintaining equal separations between the substrate and each probe, even over non-planar substrates. Here we demonstrate array-based laser nanolithography where each probe is a microsphere capable of fabricating 100 nm structures using 355 nm light when self-positioned near a surface by Bessel beam optical trapping. We achieve both a feature size uniformity and relative positioning accuracy better than 15 nm, which agrees well with our model. Further improvements are possible using higher power and/or narrower Bessel beam optical traps.
TL;DR: The scattering coefficients for a HOBB are found to equal those obtained from the study of sound scattering of plane progressive waves by an elastic sphere, suggesting that the (complex) form function presented here may be used to advantage toward studying the acoustic scattering of a HobB by spherical shells, coated spheres, and coated spherical shells using their corresponding scattering partial wave coefficients available in standard and recent literature texts.
Abstract: The exact analytical solution for the acoustic scattering of a high-order (commonly known as generalized) Bessel beam (HOBB) by an elastic sphere immersed in an ideal fluid and centered along the beam axis is revisited. The far-field acoustic scattering field is expressed as a partial wave series involving the scattering angle relative to the beam axis, the order, and the half-conical angle of the wave number components of the generalized Bessel beam. Using an appropriate grouping of terms, the expressions for the incident and scattered pressures, as well as the scattering (complex) form function provided in a recent work are transformed into expressions involving the partial wave series starting from the order m of the generalized Bessel beam. In this new formulation, the scattering coefficients for a HOBB are found to equal those obtained from the study of sound scattering of plane progressive waves by an elastic sphere. This suggests that the (complex) form function presented here may be used to advantage toward studying the acoustic scattering of a HOBB by spherical shells, coated spheres, and coated spherical shells using their corresponding scattering partial wave coefficients available in standard and recent literature texts.
TL;DR: In this paper, the authors proposed a new method for transformation of a Laguerre-Gaussian beam of azimuthal index l and radial index n = 0 (LGl, 0) into a vortex, diverging or nondiverging Bessel beam, which can have increased or decreased phase singularity order.
TL;DR: In this paper, the authors studied the creation and evolution of Airy beam accelerating vortices from the theoretical and experimental perspective, and demonstrated a different class of non-diffracting beams that do not propagate in a straight line but exhibit constant transversal acceleration.
Abstract: Non-diffracting beams, such as Bessel and Mathieu beams, offer a wide range of potential applications in
the fields of bio-photonics, micromanipulation and spectroscopy. One of the main features of these beams
is their self-healing behavior where the beams reconstruct after an obstacle. Higher order versions of these
beams incorporate non-diffracting optical singularities or vortices propagating together with the beams in a
straight line. Vortices are ubiquitous in many parts of physics and their dynamics, especially their creation
and annihilation processes are very important in fundamental physics. Newly demonstrated Airy beams
represent a different class of non-diffracting beams that do not propagate in a straight line but exhibit
a constant transversal acceleration. The self-healing properties of these Airy beams together with their
transversal acceleration can be used to optically clear entire regions of microparticles. These Airy beams
are created using a spatial light modulator that encodes a cubic phase front on an incident Gaussian beam.
Using the same method and suitable computer generated holograms we are able to generate Airy like beams
that include optical vortices. In this paper, we study the creation and evolution of Airy beam accelerating
vortices from the theoretical and experimental perspective.
TL;DR: It is remarkable that the Bessel beam generated by this hologram, at the plane of this device, has peak amplitude higher than the amplitude of the beam employed to illuminate it.
Abstract: We report a highly efficient method for generation of any high-order nondiffracting Bessel beam employing a phase hologram whose transmittance coincides with the phase modulation of such a beam. It is remarkable that the Bessel beam generated by this hologram, at the plane of this device, has peak amplitude higher than the amplitude of the beam employed to illuminate it.
TL;DR: In this article, the refraction and reflection of a Bessel beam by an uniaxial crystal is analyzed in detail using a compact mathematical formalism describing the propagation of structured electromagnetic waves impinging at arbitrary angles on a plane interface.
Abstract: The refraction and reflection of a Bessel beam by an uniaxial crystal is analyzed in detail. Use is made of a compact mathematical formalism describing the propagation of structured electromagnetic waves impinging at arbitrary angles on a plane interface. Numerical results showing the evolution of optical phase and vector vortices are presented, and the non-conservation of local angular momentum is discussed.
TL;DR: Radiation force examples obtained through numerical evaluation of the radiation force function are computed for an air bubble, a hexane, a red blood and mercury fluid spheres in water and an axial amplitude null and an azimuthal phase gradient.
Abstract: The partial wave series for the scattering of a high-order Bessel beam (HOBB) of acoustic quasi-standing waves by an air bubble and fluid spheres immersed in water and centered on the axis of the beam is applied to the calculation of the acoustic radiation force. A HOBB refers to a type of beam having an axial amplitude null and an azimuthal phase gradient. Radiation force examples obtained through numerical evaluation of the radiation force function are computed for an air bubble, a hexane, a red blood and mercury fluid spheres in water. The examples were selected to illustrate conditions having progressive, standing and quasi-standing waves with appropriate selection of the waves’ amplitude ratio. An especially noteworthy result is the lack of a specific vibrational mode contribution to the radiation force determined by appropriate selection of the HOBB parameters.
Patent•
05 Mar 2009
TL;DR: In this article, a technique for generating a Bessel beam is described, where an input optical fiber is connected to a fiber mode converting device that provides phase matching, at a predetermined excitation wavelength, between the fundamental mode and a selected azimuthally symmetric higher-order mode.
Abstract: A technique is described for generating a Bessel beam. An input optical fiber is provided that supports propagation in the fundamental mode. The input fiber is connected to a fiber mode converting device that provides phase matching, at a predetermined excitation wavelength, between the fundamental mode and a selected azimuthally symmetric higher-order mode. As an input to the fiber mode converting device, a coherent light beam is fed through the input optical fiber to provide a fundamental mode input at the excitation wavelength. The fiber mode converting device resonantly excites the selected azimuthally symmetric mode. The azimuthally symmetric mode is provided as a beam output from an endface of the fiber mode converting device to approximate a Bessel beam.
TL;DR: It is shown that a photon detector, sensitive to the magnetic field or to the gradient of electric field, can help to characterize the quantum properties of spatially-dependent optical fields.
Abstract: We show that a photon detector, sensitive to the magnetic field or to the gradient of electric field, can help to characterize the quantum properties of spatially-dependent optical fields We discuss the excitation of an atom through magnetic dipole or electric quadrupole transitions with the photons of a Bessel beam or a Laguerre-Gauss (LG) beams These spiral beams are shown to be not true hollow beams, due to the presence of magnetic fields and gradients of electric fields on beam axis This approach paves the way to an analysis at the quantum level of the propagating light beams having a complicated spatial structure
TL;DR: In this paper, a detailed analysis of localized electromagnetic waves (of the Bessel type) in the scalar approximation, after reflection on surfaces constituted by absorbing media, is presented.
TL;DR: It is concluded that the Bessel trap has a number of advantages over optical tweezers in terms of characterisation of accumulation mode particles, manipulation of particles over macroscopic length scales and effective control of the gas phase.
Abstract: Micron and sub-micron sized aerosol particles are captured, manipulated and characterised in a Bessel beam optical trap. Bright field microscopy and elastic light scattering measurements are used in combination to interrogate trapped particles and explore the optical landscape of the trap. We conclude that the Bessel trap has a number of advantages over optical tweezers in terms of characterisation of accumulation mode particles, manipulation of particles over macroscopic length scales and effective control of the gas phase. As such, the Bessel trap is a valuable addition to the aerosol optical toolkit.
TL;DR: A subwavelength annular aperture made on metallic film and deposited on a glass substrate was fabricated by electron-beam lithography and followed by a metal lift-off process to generate a long propagation range Bessel beam to propose tuning the focal length and depth of focus by changing the diameter of the SAA.
Abstract: A subwavelength annular aperture (SAA) made on metallic film and deposited on a glass substrate was fabricated by electron-beam lithography (EBL) and which was followed by a metal lift-off process to generate a long propagation range Bessel beam. We propose tuning the focal length and depth of focus (DOF) by changing the diameter of the SAA. We used finite-difference time domain (FDTD) simulations to verify our experimental data. We found that the position of the Bessel Beam focus spot (i.e. focal length) will be farther away from the SAA plane as the diameter of the SAA increases. In addition, the depth of focus (DOF) which is the length of the Bessel beam non-diffracting area, also increases as the diameter of the SAA expands.
TL;DR: An imaging principle that employs a radially polarized zeroth-order Bessel beam in the illlumination system of the localized surface plasmon microscope can contribute to increase the imaging speed of localized surface Plasmon microscopy by use of a beam scanning device.
Abstract: We propose an imaging principle that employs a radially polarized zeroth-order Bessel beam in the illlumination system of the localized surface plasmon microscope. The illumination system enables the microscope to visualize a refractive index distribution on a substrate fabricated in the Kretschmann configuration by the measurement of reflected intensity. The experimentally observed image of a particle reveals that the spatial resolution reaches the optical diffraction limit. The proposed principle can contribute to increase the imaging speed of localized surface plasmon microscopy by use of a beam scanning device.
TL;DR: A practical method is described to transform the Bessel profile of a zero-order Bessel beam into a caustic one through the use of a combination of a conical lens and a cylindrical lens, which in turn transforms the field generated by the conical Lens.
Abstract: The diffraction patterns of a conical lens illuminated by plane and spherical waves have been intensively investigated. A practical method is described to transform the Bessel profile of a zero-order Bessel beam into a caustic one through the use of a combination of a conical lens and a cylindrical lens, which in turn transforms the field generated by the conical lens. The cylindrical lens was illuminated by a zero-order Bessel beam, producing a lips caustic beam. It is shown that this type of wave tends to regenerate during propagation, although the waves are severely perturbed.
TL;DR: In this paper, the authors present an overview of recent results in the area of soliton excitation and control in optical lattices induced by different types of nondiffracting beams featuring unique symmetries.
Abstract: We present an overview of our recent results in the area of soliton excitation and control in optical lattices induced by different types of nondiffracting beams featuring unique symmetries. Optical lattices offer the possibility to engineer and to control the diffraction of light beams in media with transversally modulated optical properties, to manage the corresponding reflection and transmission bands, and to form specially designed defects. Consequently, they afford the existence of a rich variety of new families of nonlinear stationary waves and solitons, lead to new rich dynamical phenomena, and offer novel conceptual opportunities for all-optical shaping, switching and routing of optical signals encoded in soliton formats. In this overview, we consider different types of solitons, including fundamental, multipole, and vortex solitons in reconfigurable lattices optically induced by nondiffracting radially symmetric and azimuthally modulated single Bessel beams, soliton control in networks, couplers, and switches induced by several mutually coherent or incoherent Bessel beams, we address soliton properties in three-dimensional Bessel lattices, as well as in lattices produced by Mathieu and parabolic optical beams.