BROADBAND LASER FILTER

A REQUIREMENT EXISTS TO PROVIDE OCULAR PROTECTION TO TROOPS AT RISK FROM LASER ENERGY EXPOSURE AND BALLISTIC FRAGMENTS WHILE MAINTAINING ESSENTIAL VISUAL PERFORMANCE. SINCE HOSTILE LASER BEAMS MAY BE AT UNEXPECTED WAVELENGTHS, THE USUAL NOTCH FILTER IS NOT A COMPLETE ANSWER TO THE PROBLEM. THIS LABORATORY PROPOSES A COMPLETELY DIFFERENT ANSWER: AN INTERFERENCE FILTER THAT BLOCKS ALL OF THE VISIBLE SPECTRUM EXCEPT FOR THREE EXTREMELY NARROW SPECTRAL BANDS. WE HAVE SHOWN THAT SUCH A FILTER SUPPORTS EXCELLENT SEEING EVEN IN DIM LIGHT, WITH EXCELLENT VISUAL ACUITY AND EXCELLENT COLOR DISCRIMINATION, BECAUSE THE DISCARDED WAVELENGTHS ARE NOT NECESSARY TO GOOD SEEING. SUCH A FILTER OFFERS PROTECTION FROM ALL LASER WAVELENGTHS EXCEPT ONES THAT FALL EXACTLY ON ONE OF THE NARROW PASSBANDS. THIS STILL LEAVES SOME VULNERABILITY, BUT MUCH LESS THAN ANY CONVENTIONAL FILTER.