Related papers: Group velocity control in the ultraviolet domain v…
Novel optical phenomena, including electromagnetically induced transparency, slow light, superluminal light propagation, have recently been demonstrated in diverse physical implementations. These phenomena are challenging to realize in…
Group velocity control is demonstrated for x-ray photons of 14.4 keV energy via a direct measurement of the temporal delay imposed on spectrally narrow x-ray pulses. Sub-luminal light propagation is achieved by inducing a steep positive…
The formation of dark states under interaction of degenerate atomic states with incoherent broadband radiation (white light) is discussed. A simple coupling scheme in a three level Lambda-system, which allows both qualitative and…
The transient-absorption spectrum of a $V$-type three-level system is investigated, when this is periodically excited by a train of equally spaced, $\delta$-like pump pulses as, e.g., from an optical-frequency-comb laser. We show that, even…
We theoretically study the transparency and amplification of a weak probe field applied to the cavity in hy- brid systems formed by a driven superconducting circuit QED system and a mechanical resonator, or a driven optomechanical system…
Light springs are space-time beams that have a helical wavepacket. Due to this special property, light springs result into a rotating pulse when intercepting a plane lying orthogonal to their propagation direction. Associated to this, we…
Coherence phenomena in four-level atomic system, cyclicly driven by three coherent fields, are investigated thoroughly at zero and weak magnetic fields. Each strongly interacting atomic state is converted to a triplet due to a dynamical…
We explore the coherent control of nonlinear absorption of intense laser fields in four-level atomic systems. For instance, in a four-level ladder system, a coupling field creates electromagnetically induced transparency (EIT) with…
We study the absorption and dispersion properties of a weak tunable probe field in a four-level Y-type atomic system driven by two strong laser (coupling) fields within the framework of density matrix formalism. It is found that the probe…
The light propagation of a probe field pulse in a four-level double-lambda type system driven by laser fields that form a closed interaction loop is studied. Due to the finite frequency width of the probe pulse, a time-independent analysis…
It is typically assumed that the fluctuations associated with a stationary broadband incoherent field propagate in free space at the speed of light in vacuum c. Here we introduce the concept of 'coherence group velocity', which -- in…
We discuss nonlinear spectra of selective reflection from high-density rubidium atomic vapor, where the self-broadening of the resonant transition $5S_{1/2}-5P_{3/2}$ dominates over the Doppler width. In the experiments, the hole-burning…
We investigate the relationship between stability, adiabaticity and transfer efficiency in a \Lambda-type atom-molecule coupling system via a nonlinear stimulated Raman adiabatic passage. We find that only when the pump and control lasers…
The unusually narrow features in the fluorescence from Rubidium-85 driven by cooling and repumper laser fields, reported in an earlier experiment [1] are explained on the basis of a four-level density matrix calculation. Quantum effects…
We present experimental results relative to superluminal propagation based on a single photon traversing an optical system, called 4f-system, which acts singularly on the photon's spectral component phases. A single photon is created by a…
We investigate the spatio-temporal evolution of a Gaussian probe pulse propagating through a four-level $N$-type atomic medium. At two-photon resonance of probe-and control fields, weaker probe pulses may propagate through the medium with…
Group velocity dispersion (GVD) in near-resonant hot atomic vapors is difficult to measure with standard pulse broadening or interferometric techniques, as absorption, pulse distortion and nonlinearities strongly affect the probe and reduce…
We investigate a singly-charged quantum dot under a strong optical driving field by probing the system with a weak optical field. When the driving field is detuned from the trion transition, the probe absorption spectrum is shifted from the…
We experimentally and theoretically analyze the propagation of weak signal field pulses under the conditions of electromagnetically induced transparency (EIT) in hot Rb vapor, and study the effects of resonant four-wave mixing (FWM). In…
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…