Quantum cascade lasers (QCLs) are a type of semiconductor laser which utilizes epitaxially grown quantum wells that contain electrons in lasing states. The optical physics of a QCL differ from that of a diode laser. In a QCL the lasing transition occurs between states within a given quantum well. In contrast, in a diode laser transitions occur between the conduction band and valence band of the semiconductor material.
Because of the inherent access to molecule-specific fingerprints via well-pronounced fundamental vibrational, rotational, and rotovibrational transitions, quantitative information at parts-per-billion to parts-per-trillion concentration levels and beyond is achievable in solids, liquids, and gases. Mid-Infrared (MIR) of the spectrum are much more important for chemical/gases sensing because the fundamental bands of vibrations lying in these regions are 1~3 orders of magnitude stronger than their near-infrared overtones.
CO2 Absorption Spectrum
String Topology Waveguides (STWs) are comprised of a central hole surrounded by a highly reflective inner wall. STWs are of particular interest for the transmission of infrared (IR) to THz radiatio.
String Topology Waveguides (STWs)
In particular, the combination of quantum cascade lasers (QCLs) with correspondingly tailored hollow-core waveguide technologies serving as a new generation spectrometry with high sensitivity, precision, low detection limit and fast turnover rate, ideally for applications such as oil and gas exploration, climate and environment, medical and physiological, and Industrial monitoring
hollow-core waveguides optically coupled with quantum cascade lasers
