X-wave bullets with negative group velocity in vacuum

Zapata–Rodríguez, Carlos J.; Porras, Miguel A.

doi:10.1364/ol.31.003532

Cited by 32 publications

(29 citation statements)

References 15 publications

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“…Ever since Brittingham proposed in 1983 a pulsed optical beam that is transported rigidly in free space at a group velocity equal to the speed of light c [1], there has been significant interest in the study of propagationinvariant wave packets [2][3][4][5][6][7][8][9][10]. A variety of examples have been identified [11][12][13] whose group velocity in free space -intriguingly -take on arbitrary values.…”

Section: Introductionmentioning

confidence: 99%

What is the maximum differential group delay achievable by a space-time wave packet in free space?

Yessenov¹,

Mach²,

Bhaduri³

et al. 2019

Opt. Express

101

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The group velocity of 'space-time' wave packets -propagation-invariant pulsed beams endowed with tight spatio-temporal spectral correlations -can take on arbitrary values in free space. Here we investigate theoretically and experimentally the maximum achievable group delay that realistic finite-energy space-time wave packets can achieve with respect to a reference pulse traveling at the speed of light. We find that this delay is determined solely by the spectral uncertainty in the association between the spatial frequencies and wavelengths underlying the wave packet spatiotemporal spectrum -and not by the beam size, bandwidth, or pulse width. We show experimentally that the propagation of space-time wave packets is delimited by a spectral-uncertainty-induced 'pilot envelope' that travels at a group velocity equal to the speed of light in vacuum. Temporal walkoff between the space-time wave packet and the pilot envelope limits the maximum achievable differential group delay to the width of the pilot envelope. Within this pilot envelope the spacetime wave packet can locally travel at an arbitrary group velocity and yet not violate relativistic causality because the leading or trailing edge of superluminal and subluminal space-time wave packets, respectively, are suppressed once they reach the envelope edge. Using pulses of width ∼ 4 ps and a spectral uncertainty of ∼ 20 pm, we measure maximum differential group delays of approximately ±150 ps, which exceed previously reported measurements by at least three orders of magnitude.

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Section: Introductionmentioning

confidence: 99%

What is the maximum differential group delay achievable by a space-time wave packet in free space?

Yessenov¹,

Mach²,

Bhaduri³

et al. 2019

Opt. Express

101

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“…In fact, the self-healing property, which has not been mentioned yet, plays a relevant role in numerous applications, such as the optical manipulation of micro-sized particles [3], the fabrication of long polymer fibers induced by the photopolymerization [4] and microchanneling by structural modification in glass materials [5], the enhancement of energy gain in inverse free electron lasers and inverse Cerenkov accelerators [6], and the generation of Bessel photonic lattices imprinted in photorefractive crystals [7]. The possibility of independently tuning the phase and group velocities (GVs) of a BB opens the possibility of a number of applications in nonlinear optics [8,9]. In particular, a number of phenomena was observed: frequency-doubling [10] and high-order harmonics in the extreme ultraviolet [11] using BBs, resonant self-trapping of BBs in plasmas [12], the spontaneous formation of unbalanced BBs during ultrashort laser pulse filamentation in Kerr media [13], and high Raman conversion efficiency in the formation of GV-matched X-wave pulses [14].…”

Section: Introductionmentioning

confidence: 99%

Nondiffracting Bessel plasmons

Zapata–Rodríguez¹,

Vukovic²,

Belić³

et al. 2011

Opt. Express

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Abstract:We report on the existence of nondiffracting Bessel surface plasmon polaritons (SPPs), advancing at either superluminal or subluminal phase velocities. These wave fields feature deep subwavelength FWHM, but are supported by high-order homogeneous SPPs of a metal/dielectric (MD) superlattice. The beam axis can be relocated to any MD interface, by interfering multiple converging SPPs with controlled phase matching. Dissipative effects in metals lead to a diffraction-free regime that is limited by the energy attenuation length. However, the ultra-localization of the diffracted wave field might still be maintained by more than one order of magnitude.

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“…Because the projection onto the (k z , ω c )-plane is no longer a straight line, the wave packet undergoes group velocity dispersion in free space (but not in the cavity), with group velocity v g = − 1 n 2 −1 c and dispersion coefficient k 2 = ∂ 2 kz ∂ω 2 = − n 2 n 2 −1 c 2 k o , so that v g in free space is negative. Negative-v g ST wave packets have been studied theoretically [39] and realized experimentally [24], and do not violate relativistic causality [40][41][42] We carried out our experiments using two FP cavities, each formed of symmetric Bragg mirrors sandwiching a 10-µm-thick layer of SiO 2 (index of n = 1.45 at a wavelength of λ = 800 nm, leading to a free spectral range of ∼ 22 nm) deposited via e-beam evaporation. The Bragg mirrors are formed of bilayers of SiO 2 and TiO 2 (thicknesses of 138 nm and 88 nm, and indices at λ = 800 nm of 1.45 and 2.28, respectively).…”

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confidence: 99%

Omni-resonant space–time wave packets

et al. 2020

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We describe theoretically and verify experimentally a novel class of diffraction-free pulsed optical beams that are 'omni-resonant': they have the remarkable property of transmission through planar Fabry-Pérot resonators without spectral filtering even if their bandwidth far exceeds the cavity resonant linewidth. Ultrashort wave packets endowed with a specific spatio-temporal structure couple to a single resonant mode independently of its linewidth. We confirm that such 'space-time' omni-resonant wave packets retain their bandwidth (1.6 nm), spatio-temporal profile (1.3-ps pulse width, 4-µm beam width), and diffraction-free behavior upon transmission through cavities with resonant linewidths of 0.3-nm and 0.15-nm. arXiv:1912.00092v1 [physics.optics]

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X-wave bullets with negative group velocity in vacuum

Abstract: Propagation-invariant, X waves with negative group velocity are reported. Beam aperturing allows for a comprehensive analysis concerning the causality of the optical signal and forerunner formation.

Cited by 32 publications

References 15 publications

What is the maximum differential group delay achievable by a space-time wave packet in free space?

What is the maximum differential group delay achievable by a space-time wave packet in free space?

Nondiffracting Bessel plasmons

Omni-resonant space–time wave packets

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