Photodetectors Shed Light on Optical Sensing (.PDF Download)

Light is a form of electromagnetic (EM) energy that plays an important role in battlefield activities. It is being used, for example, for directed-energy weapons using high-power lasers, and is the basis for a number of different detection methods used both for tracking lasers and munitions guidance. In support of such applications is the YAG series of silicon PIN quadrant photodetector diodes from Excelitas. They provide excellent sensitivity and responsivity over the infrared (IR) range of 400 to 1,100 nm, making them strong candidates for optical detection applications at 1,064 nm. The IR detectors employ a circular active area with four pie-shaped quadrants; to minimize noise, a guard ring collects current outside the circular active area.

The YAG series includes silicon P- and N-type devices with a breakdown voltage of 180 V dc, and is designed for use at voltages from 0 to 180 V dc. Individual models include the P-type model YAG-444-4AH and N-type model YAG-444N-4AH, both with an active diameter of 11.3 mm. The P-type model YAG-555-44H, in contrast, has an active diameter of 14.1 mm. All three models are supplied in hermetic TO-36 packages for ease of handing and mounting. They can also be provided with additional window awhinti-reflection coating and built-in heaters.