
Techniques for detecting and visualizing infrared light or heat using specialized cameras or sensors.Infrared imaging is the technique of capturing and visualizing infrared radiation—light with wavelengths longer than visible light but shorter than microwaves—to create images based on heat or thermal emission. It allows us to 'see' in the dark, detect temperature differences, and observe objects that are invisible to the naked eye. This technology is crucial in fields ranging from astronomy to medicine, where it reveals thermal patterns and hidden structures.
The first infrared detectors were developed in the early 19th century, but practical infrared imaging emerged in the 20th century with military applications during World War II. Modern uncooled microbolometer arrays became widely available in the 1990s.
Infrared cameras use sensors made of materials like indium gallium arsenide (InGaAs) or microbolometers that respond to infrared photons. These sensors convert the incoming radiation into electrical signals, which are then processed to form a thermal image. Some systems use quantum well infrared photodetectors (QWIPs) or uncooled microbolometers that change resistance with temperature. The image displays temperature variations as different colors or shades of gray.
Infrared imaging is used in night vision, thermal inspection of buildings, medical thermography, firefighting, and astronomical observations of cool objects.
Infrared cameras can detect a single photon in some advanced quantum imaging setups, enabling imaging with extremely low light levels.





