Abstract

We have observed optical power limiting using a colloidal crystal doped with an organic dye. The colloidal crystal is composed of charged 0.086-μm polystyrene spheres suspended in water. For volume filling fractions of ~5%, these microspheres spontaneously form a FCC crystal structure with lattice spacing of ~250 nm. Bragg reflection from the (111) plane of the crystal is utilized to provide a highly reflective distributed feedback structure. The lattice spacing of the crystal is controlled by the filling fraction. The crystal used in the experiment is 100 μm thick and has a lattice spacing of slightly longer than 257 nm. The transmission of the crystal is studied as a function of the incident intensity for various dye concentrations and lattice spacings. The transmission of the dye-doped crystals is found to decrease dramatically with increasing intensity. The response time of the optical limiting is measured to be ~200 μs.

© 1991 Optical Society of America