Related papers: Rotational Quantum Beat Lasing Without Inversion
A cavity-free laser in the sky could lead to revolutionary improvements in optical remote sensing for atmospheric science. Abundant in air, nitrogen molecules are prime candidates as an active medium for such a laser. Nitrogen molecules,…
The effects of coherence of quantum transitions and the interference of resonant nonlinear optical processes on the spectra of absorption, amplification, and nonlinear-optical generation are considered. The most favorable conditions are…
We study the photon generation in a transmission line oscillator coupled to a driven qubit in the presence of a dissipative electromagnetic environment. It has been demonstrated previously that a population inversion in the qubit may lead…
Cavity-free lasing of N$_2^+$ induced by a femtosecond laser pulse at 800~nm is nearly totally suppressed by a delayed twin pump pulse. We explain this surprising effect within the V-scheme of lasing without population inversion. A fast…
We propose a method to achieve amplification without population inversion by anisotropic molecules whose orientation by an external electric field is state-dependent. It is based on decoupling of the lower-state molecules from the resonant…
We investigate the propagation of a coherent probe light pulse through a three-level atomic medium (in the $\Lambda$--configuration) in the presence of a pump laser under the conditions for gain without inversion. When the carrier frequency…
We show lasing without population inversion in a closed four-level atomic system which is no longer incoherently pumped on the transition at which lasing occurs. The four-level system can overcome some limits in the typical lambda-type and…
We present detailed experimental and numerical studies of random lasing in weakly scattering systems. The interference of scattered light, which is weak in the passive systems, is greatly enhanced in the presence of high gain, providing…
An influence of nonlinear interference processes at quantum transitions under strong resonance electromagnetic fields on absorption, amplification and refractive indices as well as on four-wave mixing processes is investigated. Doppler…
We explore the role of laser induced anti-alignment in enhancing molecular orientation. A field-free enhanced orientation via anti-alignment scheme is presented, which combines a linearly polarized femtosecond laser pulse with a half-cycle…
We present quantum mechanical explanations for unresolved phenomena observed in field-free molecular alignment by a femtosecond laser pulse. Quantum phase analysis of molecular rotational states reveals the physical origin of the following…
Following excitation by a strong ultra-short laser pulse, molecules develop coordinated rotational motion, exhibiting transient alignment along the direction of the laser electric field, followed by periodic full and fractional revivals…
A new kind of mechanism of lasing is investigated experimentally. It is quite different from the traditional laser with cavity and the random laser with random scattering. In this mechanism, the intensity-dependent refractive index effect…
Superradiant lasers, which consist of incoherently driven atoms coupled to a lossy cavity, are a promising source of coherent light due to their stable frequency and superior narrow linewidth. We show that when a fraction of the atoms is…
In a recent work, using a coupled microresonator system with tailored gain and loss parameters B. Peng et al. [Science 346, 328 (2014)] have experimentally reported on an apparently counterintuitive effect in laser theory, namely the…
Conventional lasers make use of optical cavities to provide feedback to gain media. Conversely, mirrorless lasers can be built by using disordered structures to induce multiple scattering, which increases the effective path length in the…
Using a master-equation approach for the description of coherent and incoherent dynamics in `artificial atoms and molecules', we present a theoretical analysis of situations where intense laser fields lead to pronounced renormalizations of…
A multi-quantum wire laser operating in the 1-D ground state has been achieved in a very high uniformity structure that shows free exciton emission with unprecedented narrow width and low lasing threshold. Under optical pumping the…
The conventional picture of the light amplification by stimulated emission of radiation (laser) is broken under the ultrastrong interaction between the electromagnetic fields and matter, and distinct dynamics of the electric field and of…
We investigate laser-induced quantum interference phenomena in superradiance processes and in an ensemble of initially excited $\Lambda-$type closely packed three-level emitters. The lower doublet levels are pumped with a coherent laser…