What are the two general types of infrared detectors?

The two general types of infrared detectors are photon detectors and thermal detectors.

Photon detectors, also known as quantum detectors, operate based on the photoelectric effect. They are sensitive to the energy of incoming infrared photons and provide high sensitivity and resolution at different wavelengths. These detectors can operate at lower temperatures, which enhances their performance in capturing infrared signals.

Thermal detectors, on the other hand, detect infrared radiation by measuring changes in temperature that result from absorption of infrared energy. These devices respond to the heat generated by incoming infrared radiation, making them effective for a broad range of infrared wavelengths. They generally offer a simpler design and are less sensitive to specific wavelengths compared to photon detectors, but they can detect higher levels of infrared radiation within their operating range.

This distinction between the detection mechanisms and operation at different ranges defines why photon and thermal detectors are recognized as the two primary categories of infrared detectors.