arXiv subjects

Ivan Oladyshkin

Publications and source records attributed to Ivan Oladyshkin.

8 recordsLinked to original sources

arXiv2026

Phonon drag as a mechanism of delayed terahertz response of metals

We show that electron drag by nonequilibrium phonons describes the actual waveform and spectrum of terahertz pulses generated during femtosecond laser irradiation of metals. In contrast to previous models, there is a picosecond delay in the drag force development due to the relatively slow lattice heating and finite phonon lifetime. We also predict that, at high pump fluences, a macroscopic deformation wave enhances nonlinearly the drag force and terahertz response. Our results establish the terahertz pulse waveform as a direct probe of ultrafast lattice dynamics in metals.

cond-mat.other↗

arXiv2022

Self-Induced Decay of Intense Laser Pulse into a Pair of Surface Plasmons

We show theoretically that an intense femtosecond optical pulse incident normally on a metal surface tends to decay into a pair of counter-propagating surface plasmon-polaritons (SPPs). The interference field heats the medium periodically, which causes a periodic permittivity perturbation and resonantly amplifies the magnitudes of SPPs. The instability growth time is only 10-50 fs for typical metals at damaging laser fluences. This mechanism is promising for the interpretation of laser-induced periodic surface structures formation in a single-pulse pumping regime.

physics.optics↗

arXiv2020

Inverse Faraday effect in graphene and Weyl semimetals

We report systematic theoretical studies of the inverse Faraday effect in materials with massless Dirac fermions, both in two dimensions such as graphene and surface states in topological insulators, and in three dimensions such as Dirac and Weyl semimetals. Both semiclassical and quantum theories are presented, with dissipation and finite size effects included. We find that the magnitude of the effect can be much stronger in Dirac materials as compared to conventional semiconductors. Analytic expressions for the optically induced magnetization in the low temperature limit are obtained. Strong inverse Faraday effect in Dirac materials can be used for the optical control of magnetization, all-optical modulation, and optical isolation.

cond-mat.mes-hall↗

arXiv2019

Optical excitation of surface plasmons and terahertz emission from metals

We propose a microscopic theory of terahertz (THz) radiation generation on metal gratings under the action of femtosecond laser pulses. In contrast to previous models, only low-frequency currents inside the metal are considered without involving electron emission. The presented model is based on plasmon-enhanced thermal effects and explains the resonant character of optical-to-THz conversion giving an adequate estimation for the full signal energy. Numerical modeling reproduces specific experimental features like delayed character of THz response and low conversion efficiency when the grating depth is too large.

physics.optics↗

arXiv2018

Second harmonic generation in graphene dressed by a strong terahertz field

We observe enhanced second-harmonic generation in monolayer graphene in the presence of an ultra-strong terahertz field pulse with a peak amplitude of 250 kV/cm. This is a strongly nonperturbative regime of light-matter interaction in which particles get accelerated to energies exceeding the initial Fermi energy of 0.2 eV over a timescale of a few femtoseconds. The second-harmonic current is generated as electrons drift through the region of momenta corresponding to interband transition resonance at an optical frequency. The resulting strongly asymmetric distortion of carrier distribution in momentum space gives rise to an enhanced electric-dipole nonlinear response at the second harmonic. We develop an approximate analytic theory of this effect which accurately predicts observed intensity and polarization of the second-harmonic signal.

cond-mat.mes-hall↗

arXiv2018

Optical properties and electromagnetic modes of Weyl semimetals

We present systematic theoretical studies of both bulk and surface electromagnetic eigenmodes, or polaritons, in Weyl semimetals. We derive the tensors of bulk and surface conductivity taking into account all possible combinations of the optical transitions involving bulk and surface electron states. We show how information about electronic structure of Weyl semimetals, such as position and separation of Weyl nodes, Fermi energy, and Fermi arc surface states, can be unambiguously extracted from measurements of the dispersion, transmission, reflection, and polarization of electromagnetic waves.

cond-mat.mes-hall↗

arXiv2017

Terahertz emission from metal nanoparticles due to ultrafast heating

We demonstrate theoretically that ultrafast heating of metal nanoparticles by the laser pulse should lead to the generation of coherent terahertz (THz) radiation during the heat redistribution process. It is shown that after the femtosecond laser pulse action the time-dependent gradient of the electronic temperature induces low-frequency particle polarization with the characteristic timescale of about fractions of picosecond. In the case of the directed metallic pattern, the THz pulse waveform can be controlled by changing geometry of the individual particle. The generation mechanism proposed in this Letter can be used for interpretation of the recent experiments on the THz generation from metallic nanoparticles and nanostructures.

physics.optics↗

arXiv2016

Laser-driven parametric instability and generation of entangled photon-plasmon states in graphene and topological insulators

We show that a strong infrared laser beam obliquely incident on graphene can experience a parametric instability with respect to decay into lower-frequency (idler) photons and THz surface plasmons. The instability is due to a strong in-plane second-order nonlinear response of graphene which originates from its spatial dispersion. The parametric decay leads to efficient generation of THz plasmons and gives rise to quantum entanglement of idler photons and surface plasmon states. A similar process can be supported by surface states of topological insulators such as Bi$_2$Se$_3$.

quant-ph↗