Single Photon Avalanche Diode (SPAD)

A Single Photon Avalanche Diode (SPAD) is a sensitive electronic device designed to detect individual particles of light, called photons. When a photon hits the SPAD, it triggers a rapid, amplified electrical signal through an avalanche process, allowing detection of extremely low light levels. SPADs are widely used in applications like medical imaging, quantum communication, and LIDAR, where precise detection of single photons is critical. They operate in a state called “Geiger mode,” where even one photon can produce a measurable electrical pulse, making them highly sensitive for advanced optical measurements.