Progress in Quantum Cascade Lasers

Non-monotonic wavelength shift of mid-infrared quantum cascade lasers at different temperatures

“…Quantum cascade lasers (QCL) [1] are unipolar semiconductor lasers based on intersubband electron transitions. They cover a wide wavelength range from mid-infrared to far-infrared, which enables important applications in free-space communication, medical diagnostics, trace gas detection, and many others [2] . Particularly, the mid-infrared region incorporates feature absorption lines of many gas molecules and falls within the atmospheric transparency window.…”