SPADpixeln

SPADpixeln is a term referring to a single-photon avalanche diode pixel. These are specialized semiconductor devices designed to detect individual photons, which are the smallest discrete units of light. Unlike conventional photodetectors that measure light intensity, SPAD pixels are capable of registering the arrival of even a single photon. This sensitivity is achieved through a phenomenon known as avalanche multiplication. When a photon strikes the SPAD pixel, it generates an electron-hole pair. This pair is accelerated by a high electric field within the diode, leading to a cascade of further electron-hole pair generations. This avalanche effect amplifies the initial signal, making it detectable. The output of a SPAD pixel is typically a digital pulse, indicating the detection of a photon. This all-or-nothing response is a key characteristic. SPAD pixels are often arranged in arrays to form single-photon avalanche diode cameras or imagers. These devices have applications in various fields, including low-light imaging, fluorescence microscopy, LiDAR (light detection and ranging) systems, quantum communication, and time-of-flight measurements due to their ability to provide timing information with high precision. The development of SPAD pixels and arrays has significantly advanced the capabilities of light detection technologies.