BISTABILITY AND ANOMALIES IN ABSORPTION AND RESONANCE SCATTERING OF INTENSE LIGHT

Under intense resonant light, the number density n of elementary excitations with well defined low energy threshold (e.g. excitons) can have more than one stationary solutions, provided that the absorption lineshape depends sensitively upon n. A variety of optical anomalies appear since the absorption, emission and scattering spectra are multivalued functions of the intensity and the frequency of incident light. A variation principle on the evolution of this open system, analogous to the second law of thermodynamics, is derived by which one can judge not only the local stability but also the global stability of the multiple stationary states. Bistable domains may be formed as a transient stage, with their boundary moving so as to expand the more stable domain, towards the global stability. © 1979.