1,720,975 research outputs found
Relationship between elegant Laguerre-Gauss and Bessel-Gauss beams
No full textWe 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 M-2. In the limit n --> infinity, 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
Few-optical-cycle Bessel-Gauss pulsed beams in free space
No full textWe introduce a new family of nonseparable, pulselike and beamlike solutions of the wave equation in the paraxial approximation with pseudonondiffracting behavior. They are the pulsed versions of the Bessel-Gauss beams by Gori et al., and encompass as particular cases the diffraction-free Bessel-X pulses, isodiffracting pulses, and, in the many-cycle limit, Bessel and Gaussian beams. Unlike Bessel-X waves, these solutions carry finite energy but retain nondiffracting behavior over a finite propagation distance, and could be physically produced with mode-locked toroidal resonators
Localized and stationary light wave modes in dispersive media
No full textIn recent experiments, localized and stationary optical wave packets have been generated in second-order nonlinear processes with femtosecond pulses, whose asymptotic features relate to those of nondiffracting and nondispersing polychromatic Bessel beams in linear dispersive media. We investigate the nature of these linear waves and show that they can be identified with the X-shaped (O-shaped) modes of the hyperbolic (elliptic)
wave equation in media with normal (anomalous) dispersion. Depending on the relative strengths of mode phase mismatch, group velocity mismatch with respect to a plane pulse, and the defeated group velocity dispersion, these modes can adopt the form of pulsed Bessel beams, focus wave modes, and X waves (O
waves), respectively
Suppression of dispersive broadening of light pulses with Bessel-Gauss beams
No full textWe show that a pulse can travel arbitrarily long distances without significant temporal spreading in a material with normal group velocity dispersion by endowing the pulse with a transversal Bessel-Gauss amplitude profile of suitable characteristics. Contrary to previous works. dispersion suppression is achieved with a finite-energy, transversally limited source, whose radius determines the largest dispersion-free propagation distance
Superluminality in Gaussian beams
No full textOn the basis of Rayleigh-Sommerfeld vectorial diffraction formulas, we show that the radiation from a pulsed Gaussian planar source propagates at a slightly superluminal group velocity beyond the Rayleigh distance, in agreement with a recent prediction from the approximate paraxial theory of diffraction. Moreover, superluminality can be sizably enhanced up to velocities 1.5% faster than c (speed of a plane wave in vacuum) by diminishing the diameter of the source down to one wavelength
Breakup of self-guided light beams into X wave trains
Full text linkRelaxation of the nonlinear spatiotemporal dynamics of cylindrically symmetric SchrÄodinger solitons due to their temporal modulation instability leads to soliton break-up into a train of X waves
Nonlinear unbalanced Bessel beams in the collapse of Gaussian beams arrested by nonlinear losses
Full text linkCollapse of a Gaussian beam in self-focusing Kerr media arrested by nonlinear losses may lead to the spontaneous formation of a quasi-stationary nonlinear unbalanced Bessel beam with finite energy, which can propagate without significant distortion over tens of diffraction lengths, and without peak intensity attenuation while the beam power is drastically diminishing
Nonlinear unbalanced O waves: nonsolitary conical light bullets in nonlinear dissipative media
No full textParaxial envelope X waves
No full textA report on the existence of luminal, localized and exactly invariant X-type solutions of paraxial wave equation in dispersive media was presented. It was observed that the eX waves play a significant role in the description of recent nonlinear, paraxial experiments with X-type pulses. It was found that the characteristics of localization and stationarity in normally dispersive media closely resemble those of self-generated X-type pulses in second-harmonic generation processes
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