Nonlinear Absorbers of Light

A nonlinear absorber of light is a substance having an unique property: its optical absorptivity is altered by light irradiation. The phenomenon is known as photochromism when the changes in optical absorbtivity are in such a wavelength range and on such a time scale as to be visually apparent. Photochromism has long been a plague to dye manufacturers. It has recently been the basis of many curious and ingenious inventions.' The present Communication is inspired by the possible use of nonlinear absorbers in various sorts of data processing applications, including multilevel logic devices. Soqmuae ntitative results pertaining to such systems are developed for a model nonlinear optical absorber and presented here