Infrared detectors are devices that sense infrared radiation, which is a type of electromagnetic radiation with wavelengths longer than visible light. These detectors are commonly used in various applications, including thermal imaging, night vision, and temperature measurement. They can detect heat emitted by objects, making them useful in fields like security, firefighting, and medical diagnostics. There are different types of infrared detectors, such as photoconductive, pyroelectric, and bolometric detectors. Each type operates based on different principles, allowing them to be tailored for specific uses. For example, bolometric detectors measure changes in temperature, while pyroelectric detectors respond to changes in infrared radiation levels.