Zero-power light-actuated micromechanical relay

This paper reports on the first demonstration of a passive light-actuated micromechanical relay (LMR). Differently from any existing switching element, the proposed LMR relies on a plasmonically-enhanced thermomechanical coupling to selectively harvest the impinging electromagnetic energy, in a specific spectral band of interest, and use it to mechanically create a conducting channel between the device terminals without the need of any additional power source, which directly translates into a near-zero standby power consumption. The first of a kind prototype presented here is selectively activated by an ultra-narrow band radiation in the mid-wavelength infrared (IR) spectral region (-5.5 μm). The strong and spectrally selective absorptivity (-95% at 5.5 μm with a full width at half maximum of ~1.1 μm) and the high thermomechanical coupling of the fabricated structure result in the first experimental demonstration of a LMR with an ultra-low actuation threshold of only 950 nW suitable for the realization of a new class of zero-power IR digitizers capable of producing a quantized output bit in the presence of a unique IR spectral signature of interest.