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Sviatoslav A. Stumpf

Sviatoslav A. Stumpf
ITMO University | SPbNRU ITMO · Department of Photonics and Optical Information Technology

к.ф.-м.н.

About

22
Publications
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94
Citations
Introduction
Sviatoslav A. Stumpf currently works at the Department of Photonics and Optical Information Technology, ITMO University. Sviatoslav does research in Computational Physics, Optics and Plasma Physics. Their most recent publication is 'Concentration dependence of terahertz generation in jets of water and ethanol mixtures'.

Publications

Publications (22)
Article
We consider the propagation of intense femtosecond pulses in a dielectric medium with an induced plasma. This plasma is excited by the strong electric field of the pulses, stimulating sequential electron transition to the conductivity band through excited discrete energy states. It is demonstrated that this simple dynamic model of ultrashort optica...
Article
The generation of terahertz (THz) radiation during the propagation of subpicosecond pulses in liquid media is investigated using a theoretical model considering the relative contribution of Kerr and plasma nonlinearity. The dependences of the THz emission generation efficiency on the contribution of plasma nonlinearity with a fixed third-order nonl...
Article
Full-text available
Polar liquids are strong absorbers of electromagnetic waves in the terahertz range, therefore, historically such liquids have not been considered as good candidates for terahertz sources. However, flowing liquid medium has explicit advantages, such as a higher damage threshold compared to solid-state sources and more efficient ionization process co...
Preprint
Full-text available
Polar liquids are strong absorbers of electromagnetic waves in the terahertz range, therefore, historically such liquids have not been considered as good candidates for terahertz sources. However, flowing liquid medium has explicit advantages, such as a higher damage threshold compared to solid-state sources and more efficient ionization process co...
Article
It is shown that the model of interaction of high-power few-cycle optical pulses with media, which is based on the density matrix formalism, is capable of simultaneously considering generation of longwave radiation in the infrared and terahertz range and describing the broadening of the radiation spectrum into the high-frequency region. The results...
Article
Full-text available
A significant number of papers investigate a propagation of intense two-color beam through air in conditions when inharmonic oscillations of valence electrons convert to a plasma nonlinearity. This paper extends the scope of analysis, examining more complex combinations of synchronized beams propagating through dielectric media: triple beam and a b...
Article
Full-text available
The paper reports results of computer simulation of strong light beam propagation in dielectric media in case of plasma generation. We investigate an extra-broadening of radiation spectrum to a 'violet' wing of visible range. We show that the resulting pulse spectrum is represented by sequence of well-separated maximums, broadening as propagation d...
Article
The paper discusses the spectral-broadening processes of femtosecond pulses in the high-frequency region when optical breakdown occurs in a gaseous medium. It is shown that the spectrum of the generated high-frequency radiation contains several isolated maxima whose positions are determined by the properties of the medium and by the thickness of th...
Article
The results of a theoretical analysis of the generation of broadband radiation in the infrared and terahertz spectral ranges upon the excitation of plasma in air by two femtosecond pulses at the fundamental and second-harmonic frequencies of a Ti-sapphire laser are presented. It is found that the appearance of long-wavelength radiation in a strong...
Article
Full-text available
Experimental results on the generation of terahertz (THz) electromagnetic radiation under ionization of air by femtosecond pulses at fundamental and second-harmonic frequencies of a Ti-sapphire laser are presented. The mean power of the generated THz radiation as a function of the time delay between two pulses of different frequencies is found to b...
Article
Full-text available
The principal regularities are determined of the self-action of high-intensity ultrashort laser pulses, caused by ionization of a dielectric medium as the pulses propagate in it. It is shown that the plasma nonlinearity generated in dielectrics in the strong fields of pulses composed of a small number of oscillations causes profiling of the emissio...
Article
A new nonlinear wave equation describing a propagation of a strong few-cycle optical pulse in isotropic dielectric media is used for an analysis of inertial polarization nonlinearity. The dependence of various inertial factors on the intensity, duration, and spectrum of radiation has been theoretically analyzed. Numerical simulation of few-cycle pu...
Article
A nonlinear wave equation suitable for describing a propagation of a light pulse containing few oscillations of a strong electric field in isotropic dielectric media is deduced. It describes non-resonant dispersion of linear refractive index and non-inertial third-order non-linearity as well as inertia of dielectric non-linearity of electron nature...
Article
A nonlinear wave equation suitable for describing a propagation of a light pulse containing few oscillations of a strong electric field in isotropic dielectric media is deduced. It describes non-resonant dispersion of linear refractive index and non-inertial third-order non-linearity as well as inertia of dielectric non-linearity of electron nature...
Article
The dependence of the conditions for the dominance of different physical factors in the self-action of few-cycle optical pulses in dielectrics on the intensity, duration, and spectrum of radiation has been theoretically analyzed. It is shown that the larger the pulse width and the central wavelength, the stronger the effect of plasma nonlinearity....
Article
Full-text available
The evolution equation was derived for the strong field of a few-cycle light pulse in an isotropic dielectric. This equation describes the nonresonant dispersion of linear refractive index, inertialess cubic nonlinearity, and the inertia of electronic nonlinearity of dielectrics (including that caused by the change in the populations and the motion...
Article
In present paper we enhance the model of polarization response in field of extremely short pulse by a pseudoclassical description of multiphoton ionization. The system of material equations now includes a part related to a ionization nonlinearity of the optical material. We also obtain a new wave equation, which describes extremely short pulse prop...
Article
To describe the dynamics of the field of supershort pulses with a continuous spectrum in transparent nonlinear media, a wave equation is derived that takes into account the dispersion not only of the linear part of the polarization response of the optical medium but also of the nonlinear part. It is shown that dispersion of the nonresonance electro...
Article
The present paper is devoted to the introduction of enhanced model describing an interaction between laser radiation and dielectric medium. This model is based on our earlier researches, and contains a correct description of the dispersion of electrical field's third order nonlinear medium polarization response in a wide spectral range. We have acc...
Article
In present paper we introduce a new model of interaction of laser radiation and dielectric medium. The model correctly describes the dispersion of third order nonlinear medium polarization response in a wide spectral range and is suitable for analysis of propagation of intensive extremely short laser pulses with a very wide spectrum. Also we includ...

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