Yuri V. Rostovtsev

X-ray quantum optics

Quantum optics with X-rays has long been a somewhat exotic activity, but it is now rapidly becoming relevant as precision x-ray optics and novel X-ray light sources, and high-intensity lasers are becoming available. This article gives an overview of the current state of the field and an outlook to future prospects.

Using quantum coherence to generate gain in the XUV and X-ray: gain-swept superradiance and lasing without inversion

It was shown some time ago that when the excitation of an ensemble of two-level atoms is swept in the direction of lasing, so that atoms are prepared in the excited state just as the radiation from previously excited atoms reaches them, the resulting laser amplifier is “highly anomalous” and yields superradiant emission without population inversion. We here show that transient gain in a three-level system has common features with Dicke superradiance and can yield strong extreme ultraviolet lasing in, for example, He atoms (at 58 nm) or He-like ions such as B3+ (at 6.1 nm).

Analytical solution to position dependent mass Schrodinger equation

Using a recently developed technique to solve the Schrödinger equation for constant mass, we have studied the regime in which the mass varies with position, i.e. the position-dependent mass Schrödinger equation (PDMSE). We obtained an analytical solution for the PDMSE and applied our approach to study a position dependent mass m(x) particle scattered by a potential . We have also studied the structural analogy between the PDMSE and the two-level atomic system interacting with a classical field.

Ultradispersive adaptive prism based on a coherently prepared atomic medium

We have experimentally demonstrated an ultra-dispersive optical prism made from coherently driven Rb atomic vapor. The prism possesses spectral angular dispersion that is six orders of magnitude higher than that of a prism made of optical glass; it is the highest spectral angular dispersion that has ever been shown (such angular dispersion allows one to spatially resolve light beams with different frequencies separated by a few kHz). The prism operates near the resonant frequency of atomic vapor and its dispersion is optically controlled by a coherent driving field.

Coherence-Driven Topological Transition in Quantum Metamaterials

We introduce and theoretically demonstrate a quantum metamaterial made of dense ultracold neutral atoms loaded into an inherently defect-free artificial crystal of light, immune to well-known critical challenges inevitable in conventional solid-state platforms. We demonstrate an all-optical control, on ultrafast time scales, over the photonic topological transition of the isofrequency contour from an open to closed topology at the same frequency. This atomic lattice quantum metamaterial enables a dynamic manipulation of the decay rate branching ratio of a probe quantum emitter by more than an order of magnitude. Our proposal may lead to practically lossless, tunable, and topologically reconfigurable quantum metamaterials, for single or few-photon-level applications as varied as quantum sensing, quantum information processing, and quantum simulations using metamaterials.

Analytical solution for 3D stationary Schrödinger equation: implementation of Huygens’ principle for matter waves

We have found an analytical solution of the 3D stationary Schrödinger equation for any arbitrary potential. The solution has been obtained by transforming the Schrödinger equation to the generalized Ricatti equation, and it has the form of Huygens’ principle for matter waves. We have shown that the solution is more accurate than the JWKB approximation. We discuss possible applications of the solution to molecular dynamics and dynamics of charges in nanostructures.

Threshold characteristics of free electron lasers without inversion

The interaction between noncolinear laser and relativistic electron beams in a static magnetic undulator has been studied within the framework of dispersion equations. For a free-electron laser without inversion (FELWI), the threshold parameters are found. The large-amplification regime should be used to bring an FELWI above the threshold laser power.

Observation of picosecond UV pulses produced by coherent scattering of IR femtosecond pulses in atomic rubidium vapor

We report the observation of coherent UV light pulses by the coherent scattering of IR pulses from atomic rubidium vapor. Rubidium atoms were first excited by a 100u2009fs pulse from the 5S ground state to the 5D state via a two-photon transition. The atoms were then pumped by an IR pulse resonant to the 5D–12P transition. The presence of the IR pulse triggered the instantaneous emission of a UV light pulse on the 12P–5S transition. The pulse had a time duration of tens of picoseconds, which was measured by a picosecond-resolution streak camera. The temporal shape of the generated light is explained by a simplified atom–field interaction theory.

Intensity correlation and anti-correlations in coherently driven atomic vapor

Motivated by the recent experiment [Sautenkov, V.A.; Rostovtsev, Yu.V.; Scully, M.O. Phys. Rev. A 2005, 72, 065801], we study the field intensity fluctuations due to interaction between a laser with a finite bandwidth and a dense atomic medium. The intensity–intensity cross-correlation of two orthogonal, circular polarized beams can be controlled by the applied external magnetic field. A smooth transition from perfect correlations to anti-correlations (at zero delay time) of the outgoing beams is observed.

Quantum optical mouse to detect Coriolis force

We describe an opto-mechanical effect that introduces an additional phase into a coherent light field. This effect is accomplished via the motion of a cavity which contains an ultradispersive medium. We have theoretically shown that this change of the phase, due to the enhanced Fizeau effect, can be used to measure displacements as small as . This technique can be used to detect the Coriolis Force.