PbSe (lead selenide) IR detector and array chips are a type of optoelectronic chip used for infrared (IR) sensing applications. PbSe is a semiconductor material that has a narrow bandgap and is therefore sensitive to IR radiation. PbSe IR detectors and arrays are often used in applications such as gas sensing, temperature measurement, and spectroscopy. The detector chips are typically composed of a thin film of PbSe deposited on a substrate, and are often packaged in a hermetic housing to protect them from the environment. PbSe IR detectors can detect radiation in the mid-wave infrared (MWIR) and long-wave infrared (LWIR) spectral regions, and typically require cooling to cryogenic temperatures for optimal performance.