We present a detailed theoretical study of transverse exciton-polariton patterns in semiconductor quantum well microcavities. These patterns are initiated by directional instabilities (driven mainly by polariton-polariton scattering) in the uniform pump-generated polariton field and are measured as optical patterns in a transverse plane in the far field. Based on a microscopic many-particle theory, we investigate the spatiotemporal dynamics of the formation, selection, and optical control of these patterns. An emphasis is placed on a previously proposed low-intensity, all-optical switching scheme designed to exploit these instability-driven patterns. Simulations and detailed analyses of simplified and more physically transparent models are used. Two aspects of the problem are studied in detail. First, we study the dependencies of the stability behaviors of various patterns, as well as transition time scales, on parameters relevant to the switching action. These parameters are the degree of built-in azimuthal anisotropy in the system and the switching (control) beam intensity. It is found that if the parameters are varied incrementally, the pattern system undergoes abrupt transitions at threshold parameter values, which are accompanied by multiple-stability and hysteresis behaviors. Moreover, during a real-time switching action, the transient dynamics of the system, in particular, the transition time scale, may depend significantly on the proximity of unstable patterns. The second aspect is a classification and detailed analysis of the polariton scattering processes contributing to the pattern dynamics, giving us an understanding of the selection and control of patterns as results of these processes' intricate interplay. The crucial role played by the (relative) phases of the polariton amplitudes in determining the gains and/or losses of polariton densities in various momentum modes is highlighted. As a result of this analysis, an interpretation of the actions of the various processes in terms of concepts commonly used in classical pattern-forming systems is given.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - May 20 2013|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics