Optical Limiters Without Focal Planes

The overall goal of the program is to develop an optical limiter without a focusing lens that provides sufficient attenuation to prevent eye damage at incident radiation levels that would otherwise cause retinal injury. High transmission (>15%), high on-state optical density (>4) and rapid response (nsec) are desired. Several new laser eye protection device designs are proposed and will be examined in detail in the course of the Phase I program. Each device exploits a fundamentally different optical limiting mechanism in organic and polymeric materials, namely nonlinear absorption, nonlinear refraction and nonlinear scattering. State-of-the-art nonlinear optical (NLO) polymers will be used as the optical limiting materials in coupled cavity, photonic band gap, and nonlinear photonic crystal device structures. Early in Phase I, potential candidate devices will be down-selected based on criteria such as limiting threshold, response time, low intensity transmission, and dynamic range among other key factors. Unique coupled cavity designs exploit intracavity enhancement without significantly limiting bandwidth. Photonic band gap devices will attempt to exploit recently developed NLO polymers with exceptional nonlinear index changes. Nonlinear scattering devices will take advantage of newly developed techniques for polymer melt infiltration into photonic crystal structures.