Fast Optical Limiters (OL) with Enhanced Dynamic Range

Optical limiters (OL) protect sensitive optical and electronic devices from laser-induced damage. The existing passive OL utilize nonlinear optical materials transmitting low-intensity light, while blocking laser radiation with intensity exceeding certain limiting threshold (LT). The common problem with the existing OL is that, at any particular frequency range, the choice of suitable nonlinear optical materials is very limited, or nonexistent. At the same time, the required value of the LT can differ dramatically in different applications. Another problem is that the nonlinear optical material is directly exposed to the high-level laser radiation, often causing overheating, dielectric breakdown, or other irreversible damage of the device. The objective of this proposal is to combine MIT developed metasurfaces, based on thin film phase change materials (GeSbSeTe), with Advanced Photon Sciences (APS) laser systems technology for large scale optical limiting applications. Phase change materials possess a large index switching behavior with a switching speed of <1ns which make them an ideal candidate for optical limiting. Advanced thin film metamaterial designs for wavelengths from 1000 2000 nm will be pursued using existing film capabilities developed recently by MIT and MIT-LL.