Optical Technology Program Optical Limiter

SRI has been involved in laser eye and sensor protection since 1983 when we invented liquid, carbon-suspension optical limiters. Carbon suspension optical limiters rely on a focused laser beam causing optical breakdown in the focal volume of the laser pulse. This results in a highly absorptive and scattering state. When there is no laser pulse present, the suspension is highly transparent with virtually no scatter. The suspensions are effective against frequency-agile, Q-switched lasers in the visible to near infrared.

Since 1983 we've performed a number of studies to characterize the response of the limiters to parameter changes such as particle concentration, path length, and f-number. The suspensions have been studied at different wavelengths in the visible, near infrared, and far infrared.