The U.S. military employs many Electro-Optical/Infrared (EO/IR) sensor platforms to enhance targeting, situational awareness, intelligence and reconnaissance operations. Pulsed lasers operating in the IR are increasingly becoming more compact and powerful and can cause permanent damage to EO/IR sensors. It is therefore important to develop EO/IR counter countermeasure technologies to protect the sensor against pulsed lasers. Self-activating optical limiters, where protection is activated by the incoming radiation are the best approach to counter frequency agile and short pulse laser threats while maintaining high transmission under normal operating conditions. However, current state of the art devices are bounded by low off-state transmittance, low laser damage threshold, high activation laser threshold, narrow field-of-view and bandwidth, and are bulky and not easily deployable. Recent advances in nanofabrication have made it possible to realize complex sub-wavelength structures which have the potential to enable further exploitation of a material's intrinsic nonlinear optical properties. Of interest are epsilon-near-zero (ENZ) materials, wherein recent developments have demonstrated a large and ultrafast nonlinear response. We will work toward the development and realization of a novel optical limiter for sensor protection using hybrid ENZ/plasmonic materials. Our analysis will include computational investigation of various optical materials and geometries.
