A wide-angle shift-free metamaterial filter design for anti-laser striking application

Laser striking is a growing safety concern for pilots and aircraft passengers and there is a great need to develop a wide-angle and shift-free laser filter and protection device. This paper presents one of such design that can effectively block out a Class 3B 532 nm green laser with an Optical Density (OD) of 1.88+ for all polarisation states over a wide range of incident angles up to 85 degree. The design consists of anti-reflection layer, active blocking and substrate layers. The central active blocking layer is designed to be a metamaterial composite media made of silver nanoparticles (AgNP) organised in a three-dimensional (3D) primitive hexagonal Bravais lattice configuration and embedded in a high-index dielectric of Zinc Sulphide (ZnS). The designed filter can be placed onto a number of devices ranging from personnel goggles to aircraft windows. The work may lead to the realisation of next generation laser protection devices that are currently sought by major aerospace companies and government defence agencies.