Saturable Fabry-Perot filter for nonlinear optical image processing

Experimental results of nonlinear optical image processing by a saturable Fabry-Perot filter are described. Fulgide, a photochromic compound, in toluene is used as a saturable absorber for the green light of an Ar-ion laser. Image thresholding using a steep increase of transmission with a critical power density of 700 mW/cm(2) is demonstrated. The spatial resolution is found to be more than 10 lines/mm over a 30-mm-diameter aperture.