RAS Institute of Applied Physics

Nizhny Novgorod, Russia

RAS Institute of Applied Physics

Nizhny Novgorod, Russia
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Khazanov E.A.,RAS Institute of Applied Physics
Physics-Uspekhi | Year: 2016

The Faraday isolator, one of the key high-power laser elements, provides optical isolation between a master oscillator and a power amplifier or between a laser and its target, for example, a gravitational wave detector interferom-eter. However, the absorbed radiation inevitably heats the magnetoactive medium and leads to thermally induced polar-ization and phase distortions in the laser beam. This self-Action process limits the use of Faraday isolators in high average power lasers. A unique property of magnetoactive medium thermooptics is that parasitic thermal effects arise on the background of circular birefringence rather than in an isotro-pic medium. Also, even insignificant polarization distortions of the radiation result in a worse isolation ratio, which is the key characteristic of the Faraday isolator. All possible laser beam distortions are analyzed for their deteriorating effect on the Faraday isolator parameters. The mechanisms responsible for and key physical parameters associated with different kinds of distortions are identified and discussed. Methods for compen-sating and suppressing parasitic thermal effects are described in detail, the published experimental data are systematized, and avenues for further research are discussed based on the results achieved. © 2016 Uspekhi Fizicheskikh Nauk, Russian Academy of Sciences.

Agency: European Commission | Branch: H2020 | Program: CSA | Phase: INFRASUPP-6-2014 | Award Amount: 1.70M | Year: 2015

This CREMLIN proposal is to foster scientific cooperation between the Russian Federation and the European Union in the development and scientific exploitation of large-scale research infrastructures. It has been triggered by the recent so-called megascience projects initiative launched by and in the Russian Federation which is now very actively seeking European integration. The proposed megascience facilities have an enormous potential for the international scientific communities and represent a unique opportunity for the EU to engage in a strong collaborative framework with the Russian Federation. The CREMLIN proposal is a first and path finding step to identify, build and enhance scientific cooperation and strong enduring networks between European research infrastructures and the corresponding megascience facilities to maximize scientific returns. The proposal follows the specific recommendations of an EC Expert Group by devising concrete coordination and support measures for each megascience facility and by developing common best practice and policies on internationalisation and opening. CREMLIN will thus effectively contribute to better connect Russian RIs to the European Research Area.

Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: SST.2008.4.1.1. | Award Amount: 4.14M | Year: 2009

The strategic objective of EXTREME SEAS is to enable European shipping industry to improve the design of ship structures that are exposed to rough climate, by providing technology and methodology that need to be a part of design for ship safety in extreme seas. The project will relate and adapt to safety regulations including Classification Societies Rules. The design procedures provided will be formulated in terms of recipes supporting harmonized standards that give presumption of conformity to the safety requirements. The project results will help shipping industry to adapt to climate change. The project addresses assessment of extreme sea states, and ship behavior in such sea states. The project will study physical and statistical properties of extreme waves, and develop advanced numerical and physical simulation models for wave-structure interaction. A further objective is to develop warning criteria for marine structures against extreme sea states and extra-ordinarily large waves, and to implement them in a marine weather forecasting system operated by a meteorological office belonging to the Consortium. The developed warning criteria will be available for decision support systems for marine structures. The developed methodology and tools will be generally applicable to different ship types. The case studies considered in EXTREME SEAS will be devoted to container vessels, to passenger ships, to LNG carriers and to product and chemical tankers. Critical responses will be investigated including green water impact on superstructures of the passenger ships. Weaknesses of the current design procedures for ship structures will be highlighted.

INRS - Institute National de la Recherche Scientifique, Ecole Polytechnique Paris Technology and RAS Institute of Applied Physics | Date: 2014-01-06

A system comprising a laser emitting an ultrashort pulse beam; and a dielectric bulk medium having a refractive index depending on intensity, the bulk medium broadening the laser beam homogeneously versus transversal spatial coordinates, and a method for compressing high energy femtosecond laser pulses, comprising propagating the laser beam inside a dielectric bulk medium having a refractive index depending on the beam intensity, the bulk medium broadening the laser beam homogeneously versus transversal spatial coordinates; and compressing a resulting broadened spectrum.

Yao X.,Texas A&M University | Tokman M.,RAS Institute of Applied Physics | Belyanin A.,Texas A&M University
Physical Review Letters | Year: 2014

Surface plasmons in graphene may provide an attractive alternative to noble-metal plasmons due to their tighter confinement, peculiar dispersion, and longer propagation distance. We present theoretical studies of the nonlinear difference frequency generation (DFG) of terahertz surface plasmon modes supported by two-dimensional layers of massless Dirac electrons, which includes graphene and surface states in topological insulators. Our results demonstrate strong enhancement of the DFG efficiency near the plasmon resonance and the feasibility of phase-matched nonlinear generation of plasmons over a broad range of frequencies. © 2014 American Physical Society.

Savilov A.V.,RAS Institute of Applied Physics
Applied Physics Letters | Year: 2010

Theory of a backward-wave electron oscillator, which operates in the nonstationary regime of the super-radiation of short powerful rf pulses, is developed. In some regimes of this auto-oscillator, complicated two-peak rf pulses are produced. It is shown that such rf pulses can be easily compressed into single-peak pulses. This provides a significant enhancement of the peak rf power. © 2010 American Institute of Physics.

Yakovlev I.V.,RAS Institute of Applied Physics
Quantum Electronics | Year: 2014

This review is concerned with pulse stretchers and compressors as key components of ultra-high power laser facilities that take advantage of chirped-pulse amplification. The potentialities, characteristics, configurations and methods for the matching and alignment of these devices are examined, with particular attention to the history of the optics of ultra-short, ultra-intense pulses before and after 1985, when the chirped-pulse amplification method was proposed, which drastically changed the view of the feasibility of creating ultra-high power laser sources. The review is intended primarily for young scientists and experts who begin to address the amplification and compression of chirped pulses, experts in laser optics and all who are interested in scientific achievements in the field of ultra-high power laser systems. © 2014 Kvantovaya Elektronika and Turpion Ltd.

Turlapov A.V.,RAS Institute of Applied Physics
JETP Letters | Year: 2012

A rapidly developing field, experimental physics of ultracold gases of Fermi atoms, is briefly reviewed. The contribution of this field to fundamental physics is shown along with connection to other fields which explore systems of Fermi particles. The basic parameters of atomic Fermi gas are described together with its unique properties and advantages and disadvantages in comparison to other Fermi systems. The prospects of this field and its short history are considered. Research groups working in this field are listed. © 2012 Pleiades Publishing, Ltd.

Makhalov V.,RAS Institute of Applied Physics | Martiyanov K.,RAS Institute of Applied Physics | Turlapov A.,RAS Institute of Applied Physics
Physical Review Letters | Year: 2014

Using an ultracold gas of atoms, we have realized a quasi-two-dimensional Fermi system with widely tunable s-wave interactions nearly in a ground state. Pressure and density are measured. The experiment covers physically different regimes: weakly and strongly attractive Fermi gases and a Bose gas of tightly bound pairs of fermions. In the Fermi regime of weak interactions, the pressure is systematically above a Fermi-liquid-theory prediction, maybe due to mesoscopic effects. In the opposite Bose regime, the pressure agrees with a bosonic mean-field scaling in a range beyond simplest expectations. In the strongly interacting regime, measurements disagree with a purely 2D model. Reported data may serve for sensitive testing of theoretical methods applicable across different quantum physics disciplines. © 2014 American Physical Society.

Dolin L.S.,RAS Institute of Applied Physics
Applied Optics | Year: 2013

We develop a method to evaluate the modulation transfer function (MTF) of a water layer from the characteristics of lidar signal backscattered by water volume. We propose several designs of a lidar system for remote measurement of the MTF and the procedure to determine optical properties of water using the measured MTF. We discuss a laser system for sea-bottom imaging that accounts for the influence of water slab on the image structure and allows for correction of image distortions caused by light scattering in water. © 2013 Optical Society of America.

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