概要（Overview）

The 81624A is an InGaAs (Indium Gallium Arsenide) optical head with a diameter of 5 millimeters, designed for precision optical measurements. It likely features a sensor made from InGaAs, a material known for its sensitivity to infrared light, making it suitable for detecting wavelengths that are beyond the capacity of standard silicon sensors. The 5mm diameter refers to the size of the sensor's active area, which is the part that captures the light. This optical head may be used in various applications such as fiber optic testing, optical power measurement, or as a component in larger optical systems.