Metal–dielectric photonic crystal superlattice: 1D and 2D models and empty lattice approximation

Periodic nanostructures are one of the main building blocks in modern nanooptics. They are used for constructing photonic crystals and metamaterials and provide optical properties that can be changed by adjusting the geometrical parameters of the structures. In this paper the optical properties of a photonic crystal slab with a 2D superlattice are discussed. The structure consists of a gold layer with a finite periodic pattern of air holes that is itself repeated periodically with a larger superperiod. We propose simplified 1D and 2D models to understand the physical nature of Wood's anomalies in the optical spectra of the investigated structure. The latter are attributed to the Rayleigh anomalies, surface plasmon Bragg resonances and the hole-localized plasmons.     

Magnetic excitons in near-surface quantum wells: Experiment and theory

We have measured the photoluminescence spectra and photoluminescence excitation spectra of magnetic excitons in InGaAs/GaAs near-surface quantum wells in a magnetic field. We have quantitatively investigated the effect of dielectric enhancement of excitons in quantum wells brought about by decreasing the thickness of the barrier layer, both in a magnetic field and without. Fiz. Tverd. Tela (St. Petersburg) 40, 806–808 (May 1998)     

Polarization instability in a polariton system in semiconductor microcavities

The kinetics of a field on a quantum well in the active region of a planar microcavity with strong exciton-photon coupling has been investigated under the conditions of resonance pulse excitation by a small degree of circular polarization. It has been shown that the system of polaritons at the early stage of the development of instability induced by polariton-polariton interaction tends to transit to a circularly polarized state, but does not reach 100% circular polarization and returns to a polarized state whose polarization is close to the pump polarization. It has been shown that the observed effects are caused by the excitation of an unpolarized reservoir of excitons in quantum wells, which leads to fast relaxation of the difference between the effective resonance frequencies of excitons with different circular polarizations.     

Inhomogeneous strains in semiconducting nanostructures

We have developed a numerical technique for calculating inhomogeneous strains in stressed semiconducting nanostructures, such as quantum wires and dots manufactured by nanolithography from stressed InGaAs/GaAs quantum wells. The technique is based on solving a linear problem of elasticity theory by the Green’s function method and presumes a lack of defects and dislocations in nanostructure heterojunctions. Spatial distributions of strain tensor components and shifts of electron and hole potentials in a nanostructure due to the strain have been calculated. Zh. éksp. Teor. Fiz. 115, 1906–1914 (May 1999)     

Decay and recondensation of electron-hole liquid in germanium under CO2 laser pulse irradiation: Investigation by microwave conductivity measurements

In microwave conductivity investigations of photoexcited germanium at low temperatures under CO₂ laser pulse irradiation the evaporation of EHL and e-h plasma formation have been observed. This plasma irreversibly vanishes at high CO₂ laser intensities I_CO2 >4 × 10⁵ W cm^?2 but recondenses at low intensities. It was found that complete and irreversible disappearance of EHL is due to the e-h plasma throw out to the crystal boundaries by phonon wind, generated in 10.6 μm radiation absorption whereas at I_CO2 > 10⁶ W cm^?2 it is connected with the crystal lattice heating over the condensation critical temperature. A theoretical analysis of the CO₂ laser produced phonon wind interaction with e-h plasma is briefly presented. By comparing with experimental data on recondensation process the phonon wind efficiency is estimated.     

Surface Tamm states in a photonic crystal slab with asymmetric termination

The reflection and transmission spectra of a finite thickness 2D photonic crystal slab (PCS) based on macroporous silicon are investigated. Periodic photonic crystal region is separated from air by homogeneous silicon interfacial layers. These interfacial layers at the silicon/air boundary being defects of the photonic crystal lattice, define the properties of surface Tamm states in the photonic stop‐bands (PSBs). It is demonstrated experimentally and theoretically that the reflection spectra of a structure with different thicknesses of the interfacial layers on both sides of the PCS depend on the illuminated side. At the same time, the transmission spectra are identical for both light directions in agreement with the reciprocity principle. Analysis shows that the dependence of the reflection spectrum on the side of light entrance is due to scattering losses in the real structure. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Kinetics of stimulated polariton scattering in planar microcavities: evidence for a dynamically self-organized optical parametric oscillator

Strong temporal hysteresis effects in the population kinetics of pumped and scattered lower polaritons (LPs) have been observed in a planar semiconductor microcavity under a nanosecond-long pulsed resonant excitation (by frequency and angle) near the inflection point of the LPs' dispersion. The hysteresis loops have a complicated shape due to the interplay of two instabilities. The self-instability (bistability) of the nonlinear pumped LP is accompanied by a strong parametric instability which causes an explosive growth of the scattered LPs' population over a wide range of wave vectors. Finally, after a 30-500 ps period, a three-mode scattering pattern forms, thereby demonstrating a dynamically self-organized regime of the optical parametric oscillator. Stability is maintained by the presence of numerous weak "above-condensate" modes; the whole system therefore appears to be highly correlated.     

Radiation from an oscillating point dipole from a photonic crystal layer of dielectric nanocolumns

The radiation pattern and intensity of the electromagnetic radiation from a point dipole source (e.g., a semiconductor quantum dot) located inside a photonic crystal layer consisting of a periodically ordered array of dielectric nanocolumns have been calculated. It has been shown that the main features of radiation can be explained considering a simple model of the interaction of the dipole with Fabry-Perrot resonances of eigenmodes of the photonic crystal layer. The total power of radiation and radiation pattern strongly depend on the position of the dipole, orientation of its dipole moment, and frequency of oscillations.