Photon detection is the process of identifying and measuring individual particles of light, known as photons. This is crucial in various fields, including quantum optics, astronomy, and medical imaging. Devices called photon detectors, such as photomultiplier tubes and avalanche photodiodes, are used to capture these light particles and convert them into electrical signals for analysis. The ability to detect photons allows scientists to study light properties and interactions at a fundamental level. It plays a significant role in technologies like laser communication and night vision devices, enhancing our understanding of the universe and improving various applications in everyday life.