Enhancement for broadband optical limiter with holographic grating

摘要

A passive broadband sensor protection and enhancement system and technique. Incident light is focused with a cylindrical lens on the optical axis into an intense light strip onto the input face of a photorefractive crystal which may include optional anti-reflection coatings on the input and output face. A broadband high reflection coating proximate to the input face reflects all radiation from approximately 0.68 out to at least 1.5 micrometers wavelength and light exiting includes a transmitted beam and beam fan. A weak holographic grating is used to seed the beam fan, such that 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.