Broadband passive optical limiter using a photorefractive crystal, cylindrical lens and filter to protect against substantially all pulsewidths and continuous wave lasers

摘要

A passive broadband sensor protection and enhancement system and technique.ncident light is focused with a cylindrical lens on the optical axis into an intense light strip onto the input face of a photorefractive crystal on the optical axis. The crystal includes optional anti- reflection coatings proximate to the input and output face. A broadband high reflection coating is proximate to the input face for reflection of all radiation from approximately 0.68 to at least out to 1. 5 micrometers wavelength. Light exiting from the output face of the crystal results from a photorefractive process that includes a transmitted beam and beam fan. The beam fan is fanned out of the optical path in a direction determined by the c-axis, dominant electro-optic coefficient, and charge carriers participating in the photorefractive process. The transmitted beam contains only incoherent radiation as input to a sensitive detector resulting in broadband multiline protection from the visible spectrum for substantially all pulsewidths and cw lasers, with enhanced time response and interaction length.