On January 1991, the esteemed Swedish professor of optics filed a patent titled "Coherence filter", that blocks coherent light regardless of laser light wavelength using destructive interference and lets through ordinary incoherent light. Sometime in 1999, several University College of London professors published "Detection of coherent light in an incoherent background"which uses both optical and digital signal processing with an interferometer to measure the self-coherence function of the incident radiation to produce an interferogram which is subsequently narrow band filtered to yield a sinc envelope.
I was wondering if it is possible to make a tunable coherence filter with 1.8 nanometer bandwidth for visible light which lets through ordinary incoherent light with less than 5db loss. The reason I chose a bandwidth of 1.8 nanometer is because Edmund Optics manufactures part 87293 which is a spectrophotometer with that wavelength resolution.
In certain applications, sensing , filtering and protection from laser radiation is required for protection of eyes.