Self-accelerating Dirac particles and prolonging the lifetime of relativistic fermions

Kaminer, Ido; Nemirovsky, Jonathan; Rechtsman, Mikael C.; Bekenstein, Rivka; Segev, Mordechai

doi:10.1038/nphys3196

Cited by 62 publications

(55 citation statements)

References 45 publications

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“…The diffraction-free beams described here provide opportunities for profoundly new applications in imaging 43 , nonlinear optics 44 , and plasma and filamentation studies 45 . Furthermore, the underlying principle of ST-beams is equally applicable to other physical waves, such as acoustic, electron, and matter waves, and potentially to elementary particle physics 46 .…”

Section: Resultsmentioning

confidence: 99%

Diffraction-free space–time light sheets

Kondakci¹,

Abouraddy²

2017

Nature Photon

299

283

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Diffraction-free optical beams propagate freely without change in shape and scale. Monochromatic beams that avoid diffractive spreading require two-dimensional transverse profiles, and there are no corresponding solutions for profiles restricted to one transverse dimension. Here, we demonstrate that the temporal degree of freedom can be exploited to efficiently synthesize onedimensional pulsed optical sheets that propagate self-similarly in free space. By introducing programmable conical (hyperbolic, parabolic, or elliptical) spectral correlations between the beam's spatio-temporal degrees of freedom, a continuum of families of axially invariant pulsed localized beams is generated. The spectral loci of such beams are the reduced-dimensionality trajectories at the intersection of the light-cone with spatio-temporal spectral planes. Far from being exceptional, self-similar axial propagation is a generic feature of fields whose spatial and temporal degrees of freedom are tightly correlated. These one-dimensional 'space-time' beams can be useful in optical sheet microscopy, nonlinear spectroscopy, and non-contact measurements.Diffractive spreading is a fundamental feature of freely propagating optical beams that is readily observed in everyday life. Diffraction sets limits on the optical resolution in microscopy, lithography, and photography; on the maximum distance for free-space optical communications and standoff detection; and on the precision of spectral analysis 1,2 . As a result, there has been a long-standing fascination with socalled 'diffraction-free' beams whose change in shape and scale during propagation is curbed when compared to other beams of comparable transverse size 3 . Monochromatic diffraction-free beams have sculpted two-dimensional (2D) transverse spatial profiles that confirm to Bessel 4 , Mathieu 5 , or Weber 6 functions, among other examples (see Refs. [7,8] for recent taxonomies). The situation is altogether different for monochromatic beams with one transverse dimension -or optical sheets -where there are only two possible diffraction-free solutions: the cosine wave that lacks spatial localization and the Airy beam that maintains a localized intensity profile but whose center-of-mass undergoes a transverse shift with propagation 9,10 . Indeed, a conclusive argument by Michael Berry 11 identified the Airy beam as the only such monochromatic one-dimensional (1D) profile. Optical nonlinearities can be exploited to thwart diffractive spreading 12,13 , and in some cases chromatic dispersion is required in the medium to restrain the diffraction of pulsed beams [14][15][16] . However, most applications require free-space diffraction-free beams.Here, we exploit the temporal degree of freedom (DoF) in conjunction with the spatial DoF to realize a variety of diffraction-free pulsed solutions having arbitrary 1D transverse profiles. By establishing a correlation between the spatial and temporal DoFs, diffractive spreading is reined-in and the time-averaged spatial profile propagates self-similarly. ...

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Section: Resultsmentioning

confidence: 99%

Diffraction-free space–time light sheets

Kondakci¹,

Abouraddy²

2017

Nature Photon

299

283

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“…This issue is of great interest today because it recently became possible to shape the quantum wave packet of a single electron [32][33][34][35], imprinting it with OAM [32][33][34][36][37][38] or with other intriguing shapes [35,39].…”

Section: Introductionmentioning

confidence: 99%

Quantum Čerenkov Radiation: Spectral Cutoffs and the Role of Spin and Orbital Angular Momentum

et al. 2016

Self Cite

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We show that the well-known Čerenkov effect contains new phenomena arising from the quantum nature of charged particles. The Čerenkov transition amplitudes allow coupling between the charged particle and the emitted photon through their orbital angular momentum and spin, by scattering into preferred angles and polarizations. Importantly, the spectral response reveals a discontinuity immediately below a frequency cutoff that can occur in the optical region. Near this cutoff, the intensity of the conventional Čerenkov radiation (ČR) is very small but still finite, while our quantum calculation predicts exactly zero intensity above the cutoff. Below that cutoff, with proper shaping of electron beams (ebeams), we predict that the traditional ČR angle splits into two distinctive cones of photonic shockwaves. One of the shockwaves can move along a backward cone, otherwise considered impossible for conventional ČR in ordinary matter. Our findings are observable for ebeams with realistic parameters, offering new applications including novel quantum optics sources, and opening a new realm for Čerenkov detectors involving the spin and orbital angular momentum of charged particles.

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“…Massless Dirac Fermions in Dirac semimetals with linear band dispersion mimic the high-energy relativistic particles in their low-energy states [1][2][3][4][5][6][7][8][9]. The high carrier velocity and the backscattering suppression [5,6,8,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] make the mobilities of Dirac semimetals extremely high, which promises revolutionary applications in electronics and optoelectronics with supreme performance.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast relaxation dynamics of photoexcited Dirac fermions in the three-dimensional Dirac semimetalCd3As2

Lu¹,

Ge²,

Liu³

et al. 2017

Phys. Rev. B

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Three dimensional (3D) Dirac semimetals which can be seen as 3D analogues of graphene have attracted enormous interests in research recently. In order to apply these ultrahigh-mobility materials in future electronic/optoelectronic devices, it is crucial to understand the relaxation dynamics of photoexcited carriers and their coupling with lattice.In this work, we report ultrafast transient reflection measurements of the photoexcited carrier dynamics in cadmium arsenide (Cd3As2), which is one of the most stable Dirac semimetals that have been confirmed experimentally. By using low energy probe photon of 0.3 eV, we probed the dynamics of the photoexcited carriers that are Dirac-Fermi-like approaching the Dirac point. We systematically studied the transient reflection on bulk and nanoplate samples that have different doping intensities by tuning the probe wavelength, pump power and lattice temperature, and find that the dynamical evolution of carrier distributions can be retrieved qualitatively by using a two-temperature model. This result is very similar to that of graphene, but the carrier cooling through the optical phonon couplings is slower and lasts over larger electron temperature range because the optical phonon energies in Cd3As2 are much lower than those in graphene.*

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Self-accelerating Dirac particles and prolonging the lifetime of relativistic fermions

Cited by 62 publications

References 45 publications

Diffraction-free space–time light sheets

Diffraction-free space–time light sheets

Quantum Čerenkov Radiation: Spectral Cutoffs and the Role of Spin and Orbital Angular Momentum

Ultrafast relaxation dynamics of photoexcited Dirac fermions in the three-dimensional Dirac semimetalCd3As2

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