Photonics - Counters, Detectors, SPCM (Single Photon Counting Module) are essential devices for photonics applications. Counters are used to tally the number of photons, detectors detect the arrival and characteristics of photons, and SPCM is a highly sensitive module specifically designed for single photon detection, capable of accurately counting individual photons. These devices find extensive applications in quantum communication, photonic computing, spectroscopy, biomedical research, and other cutting-edge fields.