Low-cost, low-power, disposable infrared markers

Light-weight, low-power consumption, low-cost IR sources are required for combat ID (IFF, identify friend or foe), trail markers, pallet markers, etc. They must be visible with conventional viewers at 200 meters in the 3-5 micron or 8-12 micron bands and emit no visible or near infrared radiation. Ion Optics has tested a prototype MEMS IR source that can meet all of these requirements. It uses a hermetically sealed filament with a photonic crystal-enhanced (PCE (TM)) coating that efficiently generates narrowband IR light. The photonic crystal surface structure limits emission to (tunable) predetermined bands (3-5 and 8-12 microns specifically). These devices generate 10mW of IR light in the 3-5 micron band with "wall-plug" efficiency of 10%, 2 orders of magnitude more efficient than conventional IR LED's. This high efficiency enables overnight battery operation. Using traditional 3-5 micron MWIR cameras, we measured visibility ranges of 200 meters. Current research and development on wafer-level packaging of the MEMS device promises to increase device yield, improve reliability, reduce package size and reduce total cost.