Exploiting Spintronics at Room Temperature for Long-Wave Infrared Nanophotonic Digital Bolometers

Digital detectors that "click" such as avalanche diodes and superconducting nanowire sensors are widely used in visible and near-infrared frequencies within the fields of quantum communications, imaging and metrology. On the other hand, the vast field of infrared bolometry has been dominated by analog detectors barring a few examples which require extremely challenging low temperature environments. Here, we propose and demonstrate a nanophotonic bolometer designed by engineering spintronic materials and dimensions to provide "clicks" from thermally activated transitions between two discrete magnetization states. We demonstrate that this nanophotonic bolometer is capable of high readout speeds of 91.6 MHz, which is faster than commercial vanadium dioxide detectors, and a noise equivalent temperature difference of ∼103 mK at 25 Hz. Further improvements to optical and thermal coupling are expected to push the sensitivity beyond even state-of-the-art cooled imagers paving the way for a new class of high-speed room temperature infrared sensors.