S. I. Vavilov State Optical Institute

Saint Petersburg, Russia

S. I. Vavilov State Optical Institute

Saint Petersburg, Russia

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Kozlov V.V.,Saint Petersburg State University | Rosanov N.N.,S. I. Vavilov State Optical Institute
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

Generation of single-cycle pulses from a laser passively mode locked by the technique of coherent mode locking is theoretically demonstrated for the case when resonant lines of both the gain and absorbing media are inhomogeneously broadened. In contrast to conventional mode-locked lasers, for which the inhomogeneous nature of line broadening sets a severe limitation on their performance, here, the stable single-cycle pulse operation is shown to persist even when the spectral widths of the inhomogeneously broadened lines of the amplifier and the absorber become nearly as wide as the central resonance frequency of their two-level transitions. This study is aimed at showing the potential for application of the coherent-mode-locking technique for quantum-dot lasers, which are typically characterized by a great amount of inhomogeneous broadening. © 2013 American Physical Society.


Kislyakov I.M.,S. I. Vavilov State Optical Institute | Yelleswarapu C.S.,University of Massachusetts Boston
Applied Physics Letters | Year: 2013

Nonlinear scattering properties of carbon black suspensions (CBS) are studied using nanosecond photoacoustic (PA) and optical z-scan techniques. When the laser is operated in multi-pulse mode, no nonlinear behavior is observed in PAZ-scans. However, in the single-pulse mode, we observed the nonlinear scattering in both PAZ and optical z- scans. Our results are in agreement with the well-known bleaching effect in CBS and demonstrate the importance of pulse repetition frequency for studying nonlinear scattering using photoacoustics. The effective nonlinear extinction coefficients of CBS were determined, and we found that PAZ-scan data are more sensitive and offer information on higher nonlinearities. © 2013 AIP Publishing LLC.


Rosanov N.N.,S. I. Vavilov State Optical Institute
Optics and Spectroscopy (English translation of Optika i Spektroskopiya) | Year: 2012

The reflection of probe radiation from a smooth inhomogeneity of characteristics of a medium that propagates with a relativistic velocity is analyzed. Equations that describe the propagation of forward and backward waves in an inhomogeneous medium are derived, conditions of occurrence of a Bragg resonance are formulated, and conditions for increasing the coefficient of reflection from the inhomogeneity are discussed. © 2012. Pleiades Publishing, Ltd.


Rosanov N.N.,S. I. Vavilov State Optical Institute
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

For a Bose-Einstein condensate in a trap with oscillating barriers, in the resonance approximation, evolution equations are derived. Their analytical solution reveals the existence of two fundamentally different types of nonlinear conservative Rabi oscillations: (i) with periodic temporal variation of moduli and phase difference of levels' amplitudes of probability, and (ii) with monotonic temporal variation of the phase difference. It is shown that the two types can be realized for the same parameters of the scheme, but for different initial conditions. Analytical predictions are confirmed by numerical solution to the Gross-Pitaevskii equation. © 2013 American Physical Society.


The possible influence of the arrangement of a sensitizing nanoobject and the charge-transfer pathway during intermolecular complex formation on nonlinear optical properties and photoconductivity characteristics of nanocomposites has been considered for a model polyimide-based nanostructured system. © 2012 Pleiades Publishing, Ltd.


Rozanov N.N.,S. I. Vavilov State Optical Institute
Journal of Experimental and Theoretical Physics | Year: 2012

The reflection of test radiation from a smooth inhomogeneity of medium characteristics propagating with a subluminal or superluminal velocity is analyzed. The equations describing the propagation of the forward- and counter-propagating waves in such an inhomogeneous medium are derived. Quasi-phase conjugation is demonstrated in the case of superluminal inhomogeneities. The Bragg resonance conditions are formulated and the conditions for increasing the reflection coefficient of radiation from an inhomogeneity are discussed. © 2012 Pleiades Publishing, Ltd.


Rosanov N.N.,S. I. Vavilov State Optical Institute
JETP Letters | Year: 2012

It has been shown that counterpropagating electromagnetic waves with different frequencies generate two lattices in a cubically nonlinear medium, one of which moves at a superluminal velocity. When weak radiation reflects from the superluminal lattice, the wavefront is quasi-conjugated with distortions owing to the Doppler frequency shift. These effects occur both in insulators with fast nonlinearity and in an electron-positron vacuum. © 2012 Pleiades Publishing, Ltd.


Rosanov N.N.,S. I. Vavilov State Optical Institute | Vysotina N.V.,S. I. Vavilov State Optical Institute
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

Dynamics of solitons in a one-dimensional trap with motionless and moving walls is studied by the example of bright solitons of an atomic Bose-Einstein condensate. Newton-type equations of the soliton's center motion are proposed and analyzed, and regimes of periodic, almost-periodic, and deterministically chaotic dynamics are presented. The predictions based on these approximate equations are in excellent agreement with that based on the Gross-Pitaevskii equation in the case of sufficiently narrow and slow solitons. © 2015 American Physical Society.


Rozanov N.N.,S. I. Vavilov State Optical Institute | Sochilin G.B.,S. I. Vavilov State Optical Institute
Journal of Experimental and Theoretical Physics | Year: 2014

The quasi-energy states have been found analytically for single quantum particles and an atomic Bose-Einstein condensate in a trap with periodically oscillating walls with a small modulation depth. A resonance is shown to exist as the modulation frequency approaches the difference of the frequencies corresponding to the levels in the unperturbed problem. Quasi-energy splitting and, accordingly, beats with a periodic population exchange between two levels in resonance have been found in the resonant case. Bistability of the response to trap size modulation, when the sustenance (depending on the initial conditions) of various quasi-energy states is possible under the same conditions, has been found for a Bose-Einstein condensate under resonance conditions. © 2014 Pleiades Publishing, Inc.


Rosanov N.N.,S. I. Vavilov State Optical Institute
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

Evolution equations are presented and discussed for an atomic Bose-Einstein condensate in a dynamical trap formed by wide oscillating barriers. Their analytical solution reveals the existence of families of bright spatial vector solitons whose components can be in phase and antiphase. © 2014 American Physical Society.

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