Laser protection system with thermally fixed hidden gratings

This project aims at developing a non focal plane laser protection system consisted of single crystal plates with hidden phase gratings, which can be revealed with exposure to strong laser pulse, and a novel optical shutter based device that follows. The protection system is large in aperture, broad in transparent window (400 nm to 2000 nm) and in field of view, and wavelength-insensitive. The protection system is capable of changing from a high transmission state (60%) to a very low transmission state (35 C 40 dB) to block light pulse within short time scale (subnanosecond). Combining phase gratings and charge compensation technique, the unique protection system has ample transmission of ambient visible light and of high optical quality in off-state, without notably degrading normal (human) vision. In the entire interesting visible waveband in this topic, even higher transmittance is anticipated with efforts on deposition of AR coatings. When harmful radiation is no longer incident, the device can recover to a high transmission state in a short time scale (microseconds) so that the users vision is not interrupted or significantly degraded after exposure. The BATis expertise in ultrafast optics, photorefraction and material fabricating and processing will meet or exceed the requirements in performance of the proposed work.