Abstract

In this contribution we focus on thermally induced dispersive and absorptive optical nonlinearities in CdSSe quantum dot glasses and CdS single crystals. We describe the self oscillations obtained experimentally by introducing the samples into a hybrid ring resonator with long round trip time. In a previous paper we reported results concerning an optically bistable CdS element in such a resonator^[1] but the descending steps of the resonator intensity as a function of time predicted by theory^[2] could not be observed. Now we use the dispersive optical nonlinearity of a quantum dot glass in reflection that yields a bistable loop with broad hysteresis and two nearly parallel stable branches. Here we can investigate the mode structrue of the self oscillation in presence of n ascending and m descending steps (n, m-mode). We find Farey tree transitions between different oscillation modes (see Fig. 1 between the (2, 5) and (2, 6) mode) that are prominent within one Farey tree family (m=const or n=const) as well as mode coexistence in the region between families (see Fig. 1 between (3, 6) and (2, 5) mode). Numerical simulations of an adiabatic model additionally show that two different kinds of mode coexistence may occur in this system.

© 1992 IQEC