Enhancement for broadband optical limiter with holographic grating

A passive broadband sensor protection and enhancement technique which achieves broadband multiline protection from the visible spectrum for substantially all pulsewidths and continuous wave lasers, with enhanced time response and interaction length, the technique including the steps of:

• providing a photorefractive crystal on the optical axis, the crystal including an input and output face;
• providing for reflection of all input radiation proximate to the input face, from approximately 0.68 to at least out to 1.5 micrometers wavelength;
• providing a weak holographic transmission grating also proximate to the input face;
• focusing incident light on the optical axis into an intense light strip coincident upon the input face relative to a plane normally referred to as the c-axis of the crystal, whereby 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 where the grating provided is used to seed the beam fan by instantaneously supplying a multiplicity of weak beams which cross the input beam at an optimum angle for two beam coupling for the crystal being used, such that the transmitted beam contains only incoherent radiation as input to a detector resulting in broadband multiline protection from the visible spectrum for substantially all pulsewidths and continuous wave lasers, with enhanced time response and interaction length.