Abstract: An optical limiter structure which includes a limiter material preferably dissolved in a host. The limiter material is selected from substituted and unsubstituted phthalocyanines, naphthalocyanines, porphyrins, salts of these materials and mixtures thereof, whereas the host is selected from any material which can dissolve the limiter material to at least the extent of 0.1% by weight.

Abstract: An optical switching device employs a rare earth bis-phthalocyanine having good third-order nonlinear susceptibilities. In a preferred optical switch, the rare earth bis-phthalocyanine is employed as a nonlinear optical material body that fills the space between two partially reflecting mirrors. When light incident on the switch is below a given intensity level, light passes through the switch and the switch is in an open state. When light is above a given intensity level, light is trapped in the nonlinear optical material and the switch is in a closed state.