arXiv subjects

V. V. Kimberg

Publications and source records attributed to V. V. Kimberg.

3 recordsLinked to original sources

arXiv2003

Adiabatic passage and dissociation controlled by interference of two laser-induced continuum structures

We have developed a theory of three-pulse coherent control of photochemical processes. It is based on adiabatic passage and quantum coherence and interference attributed to the lower-lying dissociation continuum and excited upper discrete states, which are otherwise not connected to the ground state by one-photon transitions. Novel opportunities offered by the proposed scheme are demonstrated through extensive numerical simulations with the aid of a model relevant to typical experiments. The opportunities for manipulating the distribution of the population among discrete and continuous states with any necessary ratio by the end of the pulses are demonstrated.

quant-ph↗

arXiv2003

Theory of four-wave mixing and accompanying dissociation and population transfer controlled with laser-induced continuum structures

A theory is developed and applied to the study of opportunities and specific features of coherent control of four-wave mixing as well as of the accompanying processes in the continuous-wave regime, which involve transitions between bound and free quantum states. Such opportunities become feasible through constructive and destructive interference of quantum pathways. Two coupling schemes of practical importance are investigated. In the first, a ladder energy level scheme, fully-resonant sum-frequency nonlinear-optical generation of short-wavelength radiation driven by several strong fields is investigated. The relaxation processes as well as absorption of the fundamental and generated radiations, which play an important role, are taken into consideration. It is shown that the generation output can be considerably increased through the appropriate adjustment of several laser-induced continuum structures. In the second, a folded scheme, a possible control of two-photon dissociation (Lambda-scheme) using auxiliary laser radiation applied to the adjacent bound-free transition (V-configuration) is investigated. Besides dissociation, the proposed method enables one to control population transfer between two upper discreet levels via the lower-energy dissociation continuum, while direct transition between these states is not allowed. The opportunities of manipulating these processes as well as of four-wave-mixing-based spectroscopy are explored both analytically and through a numerical simulation for Na_2 dimers.

quant-ph↗

arXiv2003

Theory of deep ultraviolet generation at maximum coherence assisted by Stark-chirped two-photon resonance

A scheme is analyzed for effcient generation of vacuum ultraviolet radiation through four-wave mixing processes assisted by the technique of Stark-chirped rapid adiabatic passage. These opportunities are associated with pulse excitation of laddertype short-wavelength two-photon atomic or molecular transitions so that relaxation processes can be neglected. In this three-laser technique, a delayed-pulse of strong oR-resonant infrared radiation sweeps the laser-induced Stark-shift of a two-photon transition in a such way that facilitates robust maximum two-photon coherence induced by the first ultraviolet laser. A judiciously delayed third pulse scatters at this coherence and generates short-wavelength radiation. A theoretical analysis of these problems based on the density matrix is performed. A numerical model is developed to carry out simulations of a typical experiment. The results illustrate a behavior of populations, coherence and generated radiation along the medium as well as opportunities of effcient generation of deep (vacuum) ultraviolet radiation.

quant-ph↗