arXiv subjects

Sergei Sokolov

Publications and source records attributed to Sergei Sokolov.

6 recordsLinked to original sources

arXiv2017

Fano lines in the reflection spectrum of directly coupled systems of waveguides and cavities: measurements, modeling and manipulation of the Fano asymmetry

We measure and analyze reflection spectra of directly coupled systems of waveguides and cavities. The observed Fano lines offer insight in the reflection and coupling processes. Very different from side-coupled systems, the observed Fano line shape is not caused by the termini of the waveguide, but the coupling process between the measurement device fiber and the waveguide. Our experimental results and analytical model show that the Fano parameter that describes the Fano line shape is very sensitive to the coupling condition. A movement of the fiber well below the Rayleigh range can lead to a drastic change of the Fano line shape.

physics.optics↗

arXiv2017

Measurement of the linear thermo-optical coefficient of Ga$_{0.51}$In$_{0.49}$P using photonic crystal nanocavities

Ga$_{0.51}$In$_{0.49}$P is a promising candidate for thermally tunable nanophotonic devices due to its low thermal conductivity. In this work we study its thermo-optical response. We obtain the linear thermo-optical coefficient $dn/dT=2.0\pm0.3\cdot 10^{-4}\,\rm{K}^{-1}$ by investigating the transmission properties of a single mode-gap photonic crystal nanocavity.

physics.optics↗

arXiv2017

Tuning out disorder-induced localization in nanophotonic cavity arrays

Weakly coupled high-Q nanophotonic cavities are building blocks of slow-light waveguides and other nanophotonic devices. Their functionality critically depends on tuning as resonance frequencies should stay within the bandwidth of the device. Unavoidable disorder leads to random frequency shifts which cause localization of the light in single cavities. We present a new method to finely tune individual resonances of light in a system of coupled nanocavities. We use holographic laser-induced heating and address thermal crosstalk between nanocavities using a response matrix approach. As a main result we observe a simultaneous anticrossing of 3 nanophotonic resonances, which were initially split by disorder.

physics.optics↗

arXiv2016

Dispersion of coupled mode-gap cavities

The dispersion of a CROW made of photonic crystal mode-gap cavities is pronouncedly asymmetric. This asymmetry cannot be explained by the standard tight binding model. We show that the fundamental cause of the asymmetric dispersion is the fact that the cavity mode profile itself is dispersive, i.e., the mode wave function depends on the driving frequency, not the eigenfrequency. This occurs because the photonic crystal cavity resonances do not form a complete set. By taking into account the dispersive mode profile, we formulate a mode coupling model that accurately describes the asymmetric dispersion without introducing any new free parameters.

physics.optics↗

arXiv2015

Explicit determination of certain periodic motions of a generalized two-field gyrostat

The case of motion of a generalized two-field gyrostat found by V.V.Sokolov and A.V.Tsiganov is known as a Liouville integrable Hamiltonian system with three degrees of freedom. We find a set of points at which the momentum map has rank 1. This set consists of special periodic motions which correspond to the singular points of a bifurcation diagram on an iso-energetic surface. For such motions the phase variables can be expressed in terms of algebraic functions of a single auxiliary variable. These algebraic functions satisfy a differential equation integrable in elliptic functions of time. It is shown that the corresponding points in the three-dimensional space of the constants of the integrals belong to the intersection of two sheets of the discriminant surface of the Lax curve.

nlin.SI↗

arXiv2015

Local thermal resonance control of GaInP photonic crystal membrane cavities using ambient gas cooling

We perform spatially dependent tuning of a GaInP photonic crystal cavity using a continuous wave violet laser. Local tuning is obtained by laser heating of the photonic crystal membrane. The cavity resonance shift is measured for different pump positions and for two ambient gases: helium and nitrogen. We find that the width of the temperature profile induced in the membrane depends strongly on the thermal conductivity of the ambient gas. For He gas a narrow spatial width of the temperature profile of 2.8 um is predicted and verified in experiment.

physics.optics↗