Showing papers on "Bessel beam published in 2001"
TL;DR: In this paper, the authors demonstrate a technique for optical manipulation of micron-sized particles, including biological samples, using a zeroth-order Bessel light beam, which offers a non-diffracting focal line of light.
548 citations
Journal Article•
TL;DR: In this article, a femtosecond microfabrication of transparent dielectrics using non-fracting Bessel beams instead of the conventionally used Gaussian beams is presented.
Abstract: We demonstrate a novel approach to femtosecond microfabrication of transparent dielectrics, which employs nondiffracting Bessel beams instead of the conventionally used Gaussian beams. The main advantage of Bessel beams is the possibility of recording linear photomodified tracks, extending along the lines of nondiffractive beam propagation without sample translation, as would be required for Gaussian beams. Recording of patterns with an aspect ratio of up to 102–103 in vitreous silica using amplified femtosecond Ti:saphire laser pulses is demonstrated.
78 citations
TL;DR: In this paper, a femtosecond microfabrication of transparent dielectrics using non-fracting Bessel beams instead of the conventionally used Gaussian beams is presented.
Abstract: We demonstrate a novel approach to femtosecond microfabrication of transparent dielectrics, which employs nondiffracting Bessel beams instead of the conventionally used Gaussian beams. The main advantage of Bessel beams is the possibility of recording linear photomodified tracks, extending along the lines of nondiffractive beam propagation without sample translation, as would be required for Gaussian beams. Recording of patterns with an aspect ratio of up to 102–103 in vitreous silica using amplified femtosecond Ti:saphire laser pulses is demonstrated.
78 citations
TL;DR: In this paper, an optical resonator that supports modes that are approximations to Bessel-Gauss beams is proposed, and the Fox-Li algorithm is applied to confirm the conclusion.
62 citations
TL;DR: In this article, it was shown that a proper choice of the crystal length or conicity angle of the incident beam permits complete transformation of a zero-order Bessel input beam into a first-order beam.
60 citations
TL;DR: In this paper, a computer-generated binary amplitude hologram is used to transform an initial Gaussian electromagnetic field with spherical phase front at 310 GHz into a non-diffracting Bessel beam.
Abstract: A computer-generated binary amplitude hologram is used to transform an initial Gaussian electromagnetic field with spherical phase front at 310 GHz into a non-diffracting Bessel beam. The beam profile is measured with the help of a near field scanner. In contrast to the situation in the optical region, both amplitude and phase information is readily obtainable from the generated field.
51 citations
TL;DR: In this paper, the authors studied the optical transformation of a zeroth-order Bessel beam to a second-order beam when the beam propa-gates along the optical axis of a uniaxial crystal.
Abstract: The optical transformation of a zeroth-order Bessel beam to a second-order Bessel beam is studied theoretically and experimentally in the case when the beam propa-gates along the optical axis of a uniaxial crystal. It is shown that, if the crystal length or the cone angle of the incident beam are chosen properly, the energy of the input field can be almost completely converted into a second-order Bessel beam.
50 citations
TL;DR: In this article, the modifications of the angular spectrum of an intense Bessel beam caused by its self-action in a nonlinear medium were revealed, and the appearance of a central spot and outer ring in its angular spectrum was observed.
50 citations
TL;DR: In this article, it was shown that the elegant Laguerre-Gauss light beams of high radial order n are asymptotically equal to Bessel Gauss light beam, and a new experimental procedure for generating light beams with nondiffractinglike properties directly from the output of a stable resonator was proposed.
Abstract: We show that the elegant Laguerre–Gauss light beams of high radial order n are asymptotically equal to Bessel–Gauss light beams. The Bessel–Gauss beam equivalent to each elegant Laguerre–Gauss beam is found and shown to have almost identical propagation factors M2. In the limit n→∞, elegant Laguerre–Gauss beams can be identified with Durnin’s Bessel beam. Our results suggest a new experimental procedure for generating light beams with nondiffractinglike properties directly from the output of a stable resonator.
50 citations
TL;DR: In this article, the free-space propagation of spatially localized ultrashort laser pulses is investigated based on a particular pulsed form of the well-known Bessel beam, which is termed a Bessel pulse beam.
Abstract: Free-space propagation of ultrashort pulses is investigated. Space-time couplings are reduced for a particular form of beams that is termed a pulse beam, or a type 3 pulsed beam. General conditions for the formation of pulse beams in the paraxial approximation are presented. The free-space propagation of spatially localized ultrashort laser pulses is investigated. This treatment is based on a particular pulsed form of the well-known Bessel beam, which is termed a Bessel pulse beam. The connections with focus wave modes and X waves are discussed.
49 citations
TL;DR: DPE’s that have high diffraction efficiency and excellent SNR can be achieved by using the algorithm that is proposed, and numerical results demonstrate that the proposed algorithm is highly efficient and robust.
Abstract: Hybrid approaches that combine genetic algorithms (GA’s) with traditional gradient-based local search techniques are proposed for the optimization design of diffractive phase elements (DPE’s) for laser beam shaping. These hybrid methods exploit the global nature of the GA’s as well as the local improvement capabilities of the gradient-based local search techniques and will perform a more improved search in comparison with each of the individual approaches. The incorporated local search technique that we used here is the Davidon–Fletcher–Powell method. A cost function that can directly control the performance of the final solutions is also used. By performing the DPE design with different desired diffraction efficiencies, we obtain a set of results that approximately reflect the trade-off between the design objectives, namely, signal-to-noise ratio (SNR) and diffraction efficiency. Reasonable solutions can be chosen on the basis of the knowledge of the problem. Simulation computations are detailed for two rotationally symmetric beam-shaping systems, in which an incident Gaussian profile laser beam is converted into a uniform beam and a zero-order Bessel beam. Numerical results demonstrate that the proposed algorithm is highly efficient and robust. DPE’s that have high diffraction efficiency and excellent SNR can be achieved by using the algorithm that we propose.
Patent•
31 May 2001TL;DR: In this paper, diffractive optical elements are used to create a Bessel-Gaussian scanning beam, which comprises a coherent combination of a Gaussian beam and Bessel beam.
Abstract: A beam generator, or beam shaping system, for example for use in an optical scanner, creates a non-Gaussian beam which provides improved indicia-reading characteristics. In one embodiment, diffractive optical elements are used to create a Bessel-Gaussian scanning beam, which comprises a coherent combination of a Gaussian beam and a Bessel beam.
TL;DR: A critical interpretation based on the analysis of plane and spherical waves shows that the superluminal effects are caused by interference phenomena as mentioned in this paper, and demonstrates that Bessel beams or X-waves are unsuitable for superluminous signal transfer.
TL;DR: In this paper, a subsonic uniformly propagating core was introduced for a sub-sonic plane wave with a subplane wave modulated by a supersonic core, which is considered an envelope for a truncated Bessel beam.
Abstract: We introduce subsonic nondiffracting waves which—unlike the ordinary supersonic nondiffracting waves—evolve periodically under propagation. Such pulse-like waves have a subsonic uniformly propagating ‘core’, which is modulated by a supersonic plane wave. The subsonic core may also be considered an envelope for a truncated Bessel beam and subsonic nondiffracting waves may be used to describe signal propagation within Bessel beams.
TL;DR: Owing to the extended interaction length along the diffraction-free propagation, higher-order Stokes components are generated in a bulk Brillouin-active medium with odd and even orders propagating in opposite directions.
Abstract: We report on an experimental investigation of stimulated Brillouin scattering pumped with a Bessel beam. Owing to the extended interaction length along the diffraction-free propagation, higher-order Stokes components are generated in a bulk Brillouin-active medium with odd and even orders propagating in opposite directions. The spatial, spectral, and temporal properties of the interacting waves are discussed.
TL;DR: In this article, the transmission of a Bessel beam through a plane-parallel layer with refractive index smaller than that of the rounding medium is studied in both scalar and vectorial approximations.
TL;DR: In this paper, the evolution of the phase front of an apertured first-order Bessel beam (J1) generated by a diffractive axicon during free-space propagation and its transformation in a Raman-resonant four-wave mixing process in hydrogen gas was studied.
Abstract: We have studied the evolution of the phase front of an apertured first-order Bessel beam (J1) generated by a diffractive axicon during free-space propagation and its transformation in a Raman-resonant four-wave mixing process in hydrogen gas. It is demonstrated that the order of the phase singularity (vortex) of a Bessel beam can easily be detected by interferometry at the boundaries of the beam propagation range. With a J1 beam and a Gaussian beam at the Stokes and the pump frequencies and vice versa, anti-Stokes light is generated as a singular, conical beam. In both cases the observed phase front agrees with theoretical predictions. In particular, the transformation of the topological charge is consistent with the conservation of angular momentum.
29 Oct 2001
TL;DR: In this article, a laser beam shaping system is investigated using genetic algorithm, in which an incident Gaussian profile laser beam is converted into a zero-order Bessel beam, and high quality DOEs can be achieved by use of the optimization procedure.
Abstract: We address a genetic algorithm (Gas) to achieve optimization design for diffractive optical elements (DOEs) for the laser beam shaping. A laser beam shaping system is investigated using genetic algorithm, in which an incident Gaussian profile laser beam is converted into a zero-order Bessel beam. This algorithm exploits the global nature of the genetic algorithms. High-quality DOEs can be achieved by use of the optimization procedure we proposed.
TL;DR: The plane z is divided into four zones which are shown in Fig. 1 for the case t = 0 and for t > 0, the diagram moves with velocity v = c/ cosθ in the direction of z-axis.
15 Mar 2001
TL;DR: In this paper, a method of rotation of higher-order Bessel light beams based on controlling phase difference between the interfering Bessel beam and a super-Gaussian or annular beam coaxial with it was proposed.
Abstract: We propose a method of rotation of higher-order Bessel light beams based on controlling phase difference between the interfering Bessel beam and a super-Gaussian or annular beam coaxial with it. TO realize the optically-controlled rotation of light field, a phase modulator based on quadratic or cubic nonlinearities can be used.
TL;DR: In this article, the authors used the linear theory of propagation of a spherical wave layer to treat the principles of simulating turbulent process and the criteria of its similarity for a flat channel defined by two walls and for a square tube.
Abstract: The linear theory of propagation of a spherical wave layer is used to treat the principles of simulating turbulent process and the criteria of its similarity. The mechanism of turbulence is given for a flat channel defined by two walls and for a square tube. We use this channel as an example to demonstrate the effect of the wave layer properties on velocity pulsations, as well as the effect of the characteristics of a sequence of disturbances on the structure of pulsations. The model is used to describe the structure of a plasma channel developed by a Bessel beam of laser radiation. The Mathematica-4 language is used for simulation.
01 Jan 2001
TL;DR: In this article, a diffractive axicon for the illumination with Gaussian beams is designed, and the stationary phase method and numerical calculation are used to analyze the diffraction integral describing the diffuse field.
Abstract: The diffractive axicon for the illumination with Gaussian beams is designed. The stationary phase method and the numerical calculation are used to analyze the diffraction integral describing the diffraction field. It is shown that with the Gaussian beam illumination of a smaller beam radius , the axicon can produces the uniform2axial2intensity with the lower oscillation frequency and the smaller oscillation amplitude. In addition , with the Gaussian beam illumination of a suitable beam radius , we can achieve the more uniform central2core width.
02 Mar 2001
TL;DR: In this paper, a new method for obtaining high-order Bessel light beams has been developed and proved theoretically and experimentally, based on the phenomenon of transformation of circularly polarized light beam passing through biaxial crystal along its binormal.
Abstract: A new method for obtaining high-order Bessel light beams has been developed and proved theoretically and experimentally. It is based on the phenomenon of transformation of circularly polarized light beam passing through biaxial crystal along its binormal. The method can provide conversion of input Gaussian beam into Bessel beam with an almost 100% efficiency. Besides this method can be used to convert high-intensity laser beams. The light field having the cross distribution in the form of spiral is obtained from the first order Bessel light beams. A possibility of formation of the zeroth and the first order Bessel light beam from Gaussian light beam in biaxial crystal without axicon is investigated theoretically.
TL;DR: In this article, an axicon which is combined a symmetrically cubic phase plate with a perfect lens is introduced, and the diffraction field behind the axicon is investigated based on stationary phase method and numerical calculation.
Abstract: In this paper, an axicon, which is combined a symmetrically cubic phase plate with a perfect lens, is introduced. Based on stationary phase method and the numerical calculation, the diffraction field behind the axicon is investigated. It is shown that, by using this kind of axicons, we can obtain the uniform-intensity focal segment within the desired range.
TL;DR: In this article, a refractive system is designed to convert a high-power annular beam into a circular Bessel beam, and the input and output surface of the proposed system is derived.
Abstract: A refractive system is designed to convert a high-power annular beam into a circular Bessel beam. The input and output surface of the proposed system is derived. We provide cubic polynomial approximation of the surface profiles. A ray tracing through the complete system is provided to verify the design. The design parameters can be selected to choose the desired beam power in the central lobe and length of the refractive system.
TL;DR: In this paper, a system for excitation of luminescence with the help of diffraction axicons with a ring aperture to detect luminescent images was proposed. But it was not shown experimentally that spatially truncated Bessel beams formed in this case provided the local excitation.
Abstract: A system is proposed for excitation of luminescence with the help of diffraction axicons with a ring aperture to detect luminescent images. The excitation beams are visualised using LiF crystal radiophotoluminophores. It is shown experimentally that spatially truncated Bessel beams formed in this case provide the local excitation of luminescence in the region of diameter 1.6μm and length 3 mm.
14 Aug 2001
TL;DR: In this article, two simple techniques of generating non diffractive fields by tunable interference interaction of the off-axis zero-order Bessel beams are proposed for illumination of an annular aperture with cosine wave and with optical field which exhibits the self-imaging phenomenon.
Abstract: Two rather simple techniques of generating the non diffractive fields by tunable interference interaction of the off-axis zero-order Bessel beams are proposed. Experimental results for illumination of an annular aperture with cosine wave and with optical field which exhibits the self-imaging phenomenon are given.
11 May 2001
TL;DR: A detailed analysis of the problem of ultrashort pulse spatial frequency effects for arrays of Gaussian-shaped elements based on angular distribution and spectral bandwidth is given.
Abstract: Summary form only given. Thin-film micro-optical components are interesting for ultrashort-pulse beam shaping and characterization because of specific advantages (low dispersion, compactness). Arrays allow to design spatially resolving autocorrelators. Recently, we demonstrated the generation of Bessel-beams from a Ti:sapphire laser for a pulse duration <30 fs in first experiments with arrays of Gaussian-shaped micro-axicons. Theoretical predictions concerning X-pulse formation by spectral interference of conical polychromatic wavepackets in THz and optical range could be verified by detecting characteristic changes of contrast. Whereas other groups used ring-shaped absorbing slits and lenses to transform small parts of the light into an optical Bessel beam, our scheme allows to transfer more energy into the interference zone and to shape a beam matrix by using refractive micro-axicon arrays. Beside the decreasing contrast with shorter pulses, spatial frequency changes were found. Blue-shift could be excluded as responsible mechanism. As a possible explanation, travel time effects were suggested which should be array-specific and neglectable for single elements. Here we give a detailed analysis of the problem of ultrashort pulse spatial frequency effects for arrays of Gaussian-shaped elements based on angular distribution and spectral bandwidth.
TL;DR: In this paper, a plane solid-state target in vacuum was arranged along the caustic of a conic lens (axicon), which focused the laser beam, and a rather intense plasma radiation was recorded in the VUV range.
Abstract: A technique of focusing the heating radiation was investigated, which makes it possible to produce an extended (under laboratory conditions, up to 1 m and over) plasma column and enables an easy output of VUV radiation. A plane solid-state target in vacuum was arranged along the caustic of a conic lens (axicon), which focused the laser beam. An analytic dependence, which describes the spatial intensity distribution of the heating radiation in the case of a nontransparent, partially reflecting target, was derived and experimentally verified. Experiments on the irradiation of an aluminium target in vacuum with a 5-J, 5-ns pulse of a neodymium-glass laser were performed. A plasma column up to 30 mm in length and no greater than 10 μm in diameter was formed. A rather intense plasma radiation was recorded in the VUV range.
TL;DR: In this paper, the effect of the deviation of practical Bessel beams from the ideal form is assessed, the influence of the particular structure of periodically poled materials is discussed, and the concept of phase-matching aperture is introduced.
Abstract: The pumping of periodically poled optical parametric oscillators (OPOs) by practically realizable Bessel beams is analysed. The effect of the deviation of practical Bessel beams from the ideal form is assessed, the influence of the particular structure of periodically poled materials is discussed, and the concept of phase-matching aperture is introduced. In a typical situation, the efficiency of a periodically poled lithium niobate OPO pumped by a practical Bessel beam has been measured; no efficiency advantage was found in comparison to the corresponding Gaussian beam pumped system or to that predicted by the standard Brosnan-Byer model.