Superconducting nanowire single-photon detectors (SNSPDs) are highly sensitive devices used to detect individual photons, which are the smallest units of light. They operate at very low temperatures, close to absolute zero, where certain materials become superconductors. When a single photon hits the nanowire, it causes a brief disruption in the superconducting state, creating a measurable electrical signal. These detectors are known for their high efficiency and fast response times, making them valuable in various applications, including quantum computing, quantum cryptography, and astronomy. Their ability to detect single photons enables advancements in technologies that rely on precise light measurements.