Related papers: Strong Reverse Saturation and Fast-Light in Ruby
We study the cancellation of differential ac Stark shifts in the 5s and 5p states of rubidium atom using the linearly and circularly polarized lights by calculating their dynamic polarizabilities. Matrix elements were calculated using a…
We calculate the response of a line emitted from a relativistic accretion disk to a continuum variation of the central illuminating source. This model might be relevant to the very broad and sometimes redshifted emission lines which have…
Copper (Cu), gold (Au) (111) crystals were illuminated with 120 fs pulses and probed by 600 fs X-ray pulses. Rocking curves were measured versus 267 nm (UV) pump- 0.154 nm probe delay time. Curve width broadening, peak diffracted intensity…
We present far-ultraviolet spectra of the classical T Tauri star RU Lupi covering the 912-1710 A spectral range, as observed by the HST/STIS and FUSE satellites. We use these spectra, which are rich in emission and absorption lines, to…
Superradiance has been extensively studied in the 1970s and 1980s in the regime of superfluores-cence, where a large number of atoms are initially excited. Cooperative scattering in the linear-optics regime, or "single-photon superradiance"…
There are two opposing models in the analysis of the slow transmission of light pulses through saturable absorbers. The canonical incoherent bleaching model simply explains the slow transmission by combined effects of saturation and of…
Doppler broadening in thermal ensembles degrades the absorption cross-section and the coherence time of collective excitations. In two photon transitions, it is common to assume that this problem becomes worse with larger wavelength…
The efficient generation of intense X-rays and $\gamma$-radiation is studied. The scheme is based on the relativistic mirror concept, {\it i.e.}, a flying thin plasma slab interacts with a counterpropagating laser pulse, reflecting part of…
Since the advent of chirped pulse amplification1 the peak power of lasers has grown dramatically and opened the new branch of high field science, delivering the focused irradiance, electric fields of which drive electrons into the…
We have studied the temporal behavior of the atomic absorption signal under resonant excitation with a continuous-wave laser radiation. Measurements done for D2 line of 85Rb with ~ 1 ns temporal resolution have shown irregular oscillatory…
Starting from the Swift sample we define a complete sub-sample of 58 bright long Gamma Ray Bursts (GRB), 55 of them (95%) with a redshift determination, in order to characterize their properties. Our sample (BAT6) allows us to study the…
Anomalous dispersion cannot occur in a transparent passive medium where electromagnetic radiation is being absorbed at all frequencies, as pointed out by Landau and Lifshitz. Here we show, both theoretically and experimentally, that…
Strong-field manipulation of autoionizing states is a crucial aspect of electronic quantum control. Recent measurements of the attosecond transient absorption spectrum of helium dressed by a few-cycle visible pulse [Ott et al.,…
We have constructed a pulsed laser system for the manipulation of cold Rb atoms. The system combines optical telecommunications components and frequency doubling to generate light at 780 nm. Using a fast, fibre-coupled intensity modulator,…
Some fraction of the material ejected in a core collapse supernova explosion may remain bound to the compact remnant, and eventually turn around and fall back. We show that the late time (> days) power associated with the accretion of this…
We present a preliminary experimental study of the dependence on optical depth of slow and stored light pulses in Rb vapor. In particular, we characterize the efficiency of slow and stored light as a function of Rb density; pulse duration,…
In very intense electromagnetic fields, the vacuum refractive index is expected to be modified due to nonlinear quantum electrodynamics (QED) properties. Several experimental tests using high intensity lasers have been proposed to observe…
Pulse propagation is considered in an inhomogeneously broadened medium of three-level atoms in a V-configuration, dressed by a counter-propagating pump pulse. A significant signal slowdown is demonstrated in this of the three frequency…
We study numerically the reflectivity of three-dimensional (3D) photonic crystals with a complete 3D photonic band gap, with the aim to interpret recent experiments. We employ the finite element method to study crystals with the cubic…
The absorption and extinction spectra of sub-wavelength cylinder arrays are shown to present two different kind of resonances. Close to the Rayleigh anomalies, the diffractive coupling with the lattice periodicity leads to sharp peaks in…