Record-breaking single-photon detector ends need for cryogenics

Researchers at ICFO have developed a groundbreaking single-photon detector capable of sensing mid-infrared photons at significantly higher temperatures—around 25 Kelvin—compared to conventional detectors that require cryogenic cooling below 1 Kelvin. This advance eliminates the need for bulky, energy-intensive cryogenic systems, making the technology more practical for integration into photonic circuits. The detector is constructed from stacked two-dimensional materials, specifically bilayer graphene sandwiched between hexagonal boron nitride layers, precisely aligned to create a moiré pattern that induces a bistability effect. This bistability allows the device to switch between two stable states when triggered by a single photon, enabling detection without ultra-low temperatures. The novel detection mechanism differs fundamentally from traditional superconducting and semiconductor detectors by operating near an electrical tipping point, where a single photon acts as a trigger to switch the device’s state. This approach enhances sensitivity to long-wavelength photons and has potential applications in astronomy, quantum communication, and medical imaging by improving the