Abstract

Composite dielectric materials, such as gold colloids, are expected to facilitate intrinsic optically bistable behavior without cavity feedback. The nonlinear response of the metallic particles has been reported¹ to exhibit bistability in the local field intensity. Experimental studies were carried out with picosecond laser systems. Accurate measurements were made of the ratio of incident to transmitted energy per pulse for increasing irradiance, but the anticipated switching behavior was not observed before optical breakdown occurred. However, conventional optical switching, which decreases the ratio, was detected for aqueous gold colloids at irradiances of typically 100 GW/cm²—well below picosecond optical-breakdown thresholds. Such high irradiances are required because of the weak nonlinear optical coupling of the gold colloids.

© 1990 Optical Society of America