Abstract

Intrinsic optical bistability has aroused a great deal of interest due to its large application domain. Miller¹ developed a theoretical description of this process and showed its universality, indicating that intrinsic bistability results from the coexistence of two nonequilibrium states characterized by different optical properties. Such a general behavior has also been analyzed theoretically² in the particular case of laser-induced first-order phase transition between two phases of different absorptions. However, experimentally, an amazing contrast with idealized first-order transition generally occurs. Thus, a medium that transforms from one phase to another often has no sharp transition at all, and hysteresis becomes the key phenomenon. In this paper, we present a new mechanism, which involves a laser-induced phase separation without any temperature changes; we report the first experimental investigation of a real optical hysteresis; and we develop a magnetic analogy to show that this behavior originates from common general requirements of hysteretical systems.

© 1994 IEEE