Microelectromechanical detector of infrared spectral signatures with near-zero standby power consumption

This paper reports the first experimental demonstration of a near-zero power (<1 pW standby power consumption) detector of infrared (IR) spectral signatures. The proposed passive digitizer of IR spectral signatures is composed of 2 Plasmonically-enhanced MEMS Relays (PMRs) implementing a logic circuit. Unlike solid-state photodetectors, the PMRs exploit a plasmonically-enhanced thermomechanical coupling to selectively harvest the energy contained in an IR spectral band of interest itself and use it to mechanically create a conducting channel between the battery and the load without consuming any power in standby (i.e. while in the OFF state). In this work, we demonstrate for the first time, that by connecting in series 2 PMRs, tuned to different spectral bands (i.e. 4.1 μm and 5.6 μm), it is possible to implement a passive logic circuit capable of producing an output voltage (i.e. a quantized output bit that wakes up the active wireless sensor) only when exposed to the IR spectral signature associated to a target of interest (i.e. the exhaust plume of a vehicle). The event-driven sensing capability enabled by such a micro-scale IR digitizer can dramatically extend the battery life of wireless sensor nodes remotely deployed to detect infrequent but time critical events.