Quantum cascade lasers (QCL)

Quantum cascade lasers (QCLs) are specialized semiconductor devices that produce very precise, high-frequency light, often in the mid-infrared to terahertz range. Unlike traditional lasers that rely on electron-hole recombination, QCLs generate light through electrons cascading down multiple energy levels in a layered structure, releasing a photon at each step. This design allows for tunable, efficient, and coherent light sources useful in applications like spectroscopy, environmental monitoring, and medical diagnostics. Their unique quantum-engineered structure enables them to operate at wavelengths and power levels difficult to achieve with conventional lasers.