A quantum cascade laser (QCL) is a type of semiconductor laser that operates in the mid- to far-infrared region of the electromagnetic spectrum. It utilizes a specialized design of multiple quantum well layers to generate laser light.
A QCL works by using the energy levels of electrons in a series of quantum well layers to produce stimulated emission of photons. As electrons move through the layers, they emit photons with specific energies, resulting in a laser beam.
QCLs have several advantages over other types of lasers, including high output power, high efficiency, and tunability across a wide range of wavelengths. They can also operate at room temperature and have a relatively long lifespan.
QCLs have a wide range of applications, including remote sensing, spectroscopy, and medical diagnostics. They are also used in military and security systems, such as infrared countermeasures and thermal imaging.
The theoretical limit of power for a QCL is determined by the material properties and design of the device. Currently, the highest output power achieved by a QCL is around 2 watts, but research is ongoing to increase this limit.