English
Related papers

Related papers: Negative Group Delay and Superluminal Propagation:…

200 papers

We show theoretically the presence of electromagnetically induced transparency (EIT) like feature in a {\Lambda}-type atom-molecule coupled system. We demonstrate that EIT in such a systems has a sharp dispersion characteristic which is…

Optics · Physics 2022-11-23 Sandeep Sharma , Bimalendu Deb , Tarak N. Dey

We apply the framework developed in the preceding paper in this series (Smilansky 2017 J. Phys. A: Math. Theor. 50, 215301) to compute the time-delay distribution in the scattering of ultra short radio frequency pulses on complex networks…

Mathematical Physics · Physics 2018-01-23 Uzy Smilansky , Holger Schanz

We show how two circular polarization components of a linearly polarized pulse, propagating through a coherently driven dilute atomic vapor, can be well resolved in time domain by weak measurement. Slower group velocity of one of the…

Quantum Physics · Physics 2016-07-28 Pardeep Kumar , Shubhrangshu Dasgupta

We consider pulse propagation in a linear anomalously dispersive medium where the group velocity exceeds the speed of light in vacuum (c) or even becomes negative. A signal velocity is defined operationally based on the optical…

Optics · Physics 2009-11-07 A. Kuzmich , A. Dogariu , L. J. Wang , P. W. Milonni , R. Y. Chiao

One-dimensional defect photonic crystal (Bragg waveguide) is studied from the viewpoint of the slow light problem. The calculations are presented showing that in the TiO$_2$/SiO$_2$-based Bragg waveguide one can obtain the group index of…

Optics · Physics 2008-11-07 G. G. Kozlov , V. S. Zapasskii , V. V. Ovsyankin

Although the group delay of classical pulses through a barrier may suggest superluminality, the information transfer is limited by the precursor which propagates at the vacuum light speed. Single photons, however, have infinite tails, and…

Quantum Physics · Physics 2024-09-24 Jan Gulla , Johannes Skaar

The distribution of scattering delay times is analyzed for classical electrons which are transmitted through a finite waveguide. For non-zero magnetic field the distribution shows a regular pattern of maxima (logarithmic singularities).…

Mesoscale and Nanoscale Physics · Physics 2017-09-27 Manamohan Prusty , Holger Schanz

The properties of group delay for Dirac particles traveling through a potential well are investigated. A necessary condition is put forward for the group delay to be negative. It is shown that this negative group delay is closely related to…

Quantum Physics · Physics 2009-11-10 Xi Chen , Chun-Fang Li

The ability to slow down light at the single-photon level has applications in quantum information processing and other quantum technologies. We demonstrate two methods, both using just a single artificial atom, enabling dynamic control over…

We consider group delay and broadening using two strongly absorbing and widely spaced resonances. We derive relations which show that very large pulse bandwidths coupled with large group delays and small broadening can be achieved. Unlike…

Optics · Physics 2009-11-13 Ryan M. Camacho , Michael V. Pack , John C. Howell

The mechanisms leading to a seemingly superluminal propagation of light in dispersive media are examined. The anomalous dispersion near an absorption line, involved in the first experiments displaying negative group velocity propagation, is…

Classical Physics · Physics 2007-05-23 Bruno Macke , Bernard Segard

We report the experimental demonstration of the superluminal propagation of multi-spatial-mode images via four-wave mixing in hot atomic vapor, in which all spatial sub-regions propagate with negative group velocities. We investigate the…

Quantum Physics · Physics 2012-06-06 Ryan T. Glasser , Ulrich Vogl , Paul D. Lett

It is shown that the transmission and reflection group delay times in an asymmetric single quantum barrier are greatly enhanced by the transmission resonance when the energy of incident particles is larger than the height of the barrier.…

Quantum Physics · Physics 2007-05-23 Chun-Fang Li

In this paper, we propose an asymmetric distribution of a hexagonal lattice for achieving near-zero group velocity with negative group delay. This study reports the effect of the continuous geometric perturbation on the photonic band…

Optics · Physics 2021-12-21 Shahram Moradi

Scattering of ultraintense short laser pulses off relativistic electrons allows one to generate a large number of X- or $\gamma$-ray photons with the expense of the spectral width---temporal pulsing of the laser inevitable leads to…

Plasma Physics · Physics 2019-05-29 Daniel Seipt , Vasily Yu. Kharin , Sergey G. Rykovanov

We examine how the interference of a coherent light-pulse with its slightly time-delayed copy may generate a pulse nearly identical to the original one and ahead of it. The simplicity of this 2-pulse system enabled us to obtain exact…

Optics · Physics 2016-08-14 Bruno Macke , Bernard Ségard

An excitable semiconductor micropillar laser with delayed optical feedback is able to regenerate pulses by the excitable response of the laser. It has been shown that almost any pulse sequence can, in principle, be excited and regenerated…

We propose a method for slowing down light pulses by using composites doped with metal nanoparticles. The underlying mechanism is related to the saturable absorption near the plasmon resonance in a pump-probe regime, leading to strong…

Optics · Physics 2015-06-11 Kwang-Hyon Kim , Anton Husakou , Joachim Herrmann

Subvacuum effects arise in quantum field theory when a classically positive quantity, such as the local energy density, acquires a negative renormalized expectation value. Here we investigate the case of states of the quantized…

Quantum Physics · Physics 2019-03-01 V. A. De Lorenci , L. H. Ford

Theoretical and numerical wave propagation analysis of an oscillating electric dipole is presented. The results show that upon creation at the source, both the longitudinal electric and transverse magnetic fields propagate superluminally…

General Physics · Physics 2007-05-23 William D. Walker