arXiv subjects

E. D. Cherotchenko

Publications and source records attributed to E. D. Cherotchenko.

6 recordsLinked to original sources

arXiv2024

Optical Snake States in Photonic Graphene

We propose an optical analogue of electron snake states based on artificial gauge magnetic field in photonic graphene with effective strain implemented by varying distance between pillars. We develop an intuitive and exhaustive continuous model based on tight-binding approximation and compare it with numerical simulations of a realistic photonic structure. The allowed lateral propagation direction is shown to be strongly coupled to the valley degree of freedom and the proposed photonic structure may be used a valley filter.

cond-mat.mes-hall↗

arXiv2021

Observation of long turn-on delay in pulsed quantum cascade lasers

We present an experimental study of the turn-on delay in pulsed mid-infrared quantum cascade lasers. We report the unexpectedly long delay time depending on the pumping current, which does not agree with conventional theoretical predictions for step-like excitation. Similar behavior has been observed in InP- and InAs-based QCLs emitting near 8$μ$m. Numerical simulations performed using a model based on rate equations for excitation by current pulses with non-zero rise time provide fair agreement with our observations.

physics.optics↗

arXiv2020

Optically controlled polariton condensate molecules

A condensed matter platform for analogue simulation of complex two-dimensional molecular bonding configurations, based on optically trapped exciton-polariton condensates is proposed. The stable occupation of polariton condensates in the excited states of their optically configurable potential traps permits emulation of excited atomic orbitals. A classical mean field model describing the dissipative coupling mechanism between p-orbital condensates is derived, identifying lowest threshold condensation solutions as a function of trap parameters corresponding to bound and antibound $π$ and $σ$ bonding configurations, similar to those in quantum chemistry.

cond-mat.mes-hall↗

arXiv2016

Light propagation in tunable exciton-polariton one-dimensional photonic crystals

Simulations of propagation of light beams in specially designed multilayer semiconductor structures (one-dimensional photonic crystals) with embedded quantum wells reveal characteristic optical properties of resonant hyperbolic metamaterials. A strong dependence of the refraction angle and the optical beam spread on the exciton radiative lifetime is revealed. We demonstrate the strong negative refraction of light and the control of the group velocity of light by an external bias through its effect upon the exciton radiative properties.

cond-mat.mes-hall↗

arXiv2015

Dynamics of the Energy Relaxation in a Parabolic Quantum Well Laser

We explore two parabolic quantum well (PQW) samples, with and without Bragg mirrors, in order to optimise the building blocks of a Bosonic Cascade Laser. The photoluminescence spectra of a PQW microcavity sample is compared against that of a conventional microcavity with embedded quantum wells (QWs) to demonstrate that the weak coupling lasing in a PQW sample can be achieved. The relaxation dynamics in a conventional QW microcavity and in the PQW microcavity was studied by a non-resonant pump-pump excitation method. Strong difference in the relaxation characteristics between the two samples was found. The semi-classical Boltzmann equations were adapted to reproduce the evolution of excitonic populations within the PQW as a function of the pump power and the output intensity evolution as a function of the pump-pump pulse delay. Fitting the PQW data confirms the anticipated cascade relaxation, paving the way for such a system to produce terahertz radiation.

cond-mat.mes-hall↗

arXiv2014

Superconductivity in Semiconductor Structures: the Excitonic Mechanism

We study theoretically the effect of the fermion and boson densities on the superconductivity transition critical temperature $(T_c)$ of a two dimensional electron gas (2DEG), where superconductivity is mediated by a Bose-Einstein condensate of exciton-polaritons. The critical temperature is found to increase with the boson density, but surprisingly it decreases with the 2DEG density increase. This makes doped semiconductor structures with shallow Fermi energies better adapted for observation of the exciton-induced superconductivity than metallic layers. For the realistic GaAs-based microcavities containing-doped and neutral quantum wells we estimate $T_c$ as close to 50K. Superconductivity is suppressed by magnetic fields of the order of 4T due to the Fermi surface renormalisation.

cond-mat.supr-con↗