We demonstrate a prototype sensor based on a new eye-safe detection strategy with the potential to report the presence
trace explosives from standoff distances of up to 100 m. The method detects the reflected infrared radiation from groups
of micron-sized chemically-sensitized metallodielectric nanostructures. Specifically, the sensors change from reflecting
to absorbing nearly 100% of the incident probe beam radiation over a narrow band of mid-IR wavelengths when
explosive vapor is present. This strategy is not limited to the detection to explosives, but can also be used to detect other
threats by modifying the chemically-sensitive layers of the nanostructure.