Ultralow-Power Instant-On Photon-Pair Counting And Photon-Entanglement Analysis

The latest breakthroughs in quantum technologies, such as satellite quantum communications, present new challenges, imposing stringent restrictions on weight, size, and power consumption of quantum information systems. Here, we show that nonlinear and quantum optics provides powerful resources to confront these challenges by offering attractive solutions for photon-pair counting and quantum-entanglement detection. We demonstrate a low-cost, readily miniaturizable photon-pair counting module, which consumes less than 100 mu Ah during a sub-10 ms power-on/off measurement cycle, thus providing a meaningful performance as a promising component for satellite quantum technologies.