Hamamatus APD （雪崩式光電二極體）是一種高靈敏度的光電二極體，透過施加反向偏壓能夠以高速度和高增益，提供了相較於PIN光電二極體更高的訊雜比，被廣泛應用於光學測距儀，空間光傳輸，閃爍檢測器等。
Hamamatsu Photonics APD (avalanche photodiode) is a high sensitivity photodiode that operates at high speeds and high gain by applying a reverse bias. Delivers a higher S/N than PIN photodiodes and is widely used in optical rangefinders, spatial light transmission, scintillation detectors, etc.
The APD is a high-speed, high-sensitivity photodiode that internally multiplies photocurrent when reverse voltage is applied. The APD, having a signal multiplication function inside its element, achieves higher S/N than the PIN photodiode and can be used in a wide range of applications such as high-accuracy rangefinders and low-light-level detection that use scintillators. Though the APD can detect lower level light than the PIN photodiode, it does require special care and handling such as the need for higher reverse voltage and more detailed consideration of its temperature-dependent gain characteristics.