Quantum Cascade Lasers

Quantum Cascade Lasers (QCLs) are specialized light sources that emit laser light in the mid-infrared to terahertz range. They work by electrons moving through a series of thin semiconductor layers, where each "step" in the process releases a photon—light particle. This layered structure, called a quantum well, is engineered so electrons cascade down multiple steps, producing a powerful, coherent beam of light with specific wavelengths. QCLs are used in applications like environmental sensing, medical diagnostics, and spectroscopy due to their ability to generate precise infrared light efficiently and tunably.