Applications of Quantum Cascade Lasers in Spectroscopy and Trace Gas Analysis

The primary emphasis of this research paper lies in advancing versatile quantum cascade laser-based spectroscopic methods tailored for highly sensitive gas detection. These techniques hold promise for a range of applications including atmospheric sensing, biomedical science, and high-resolution fundamental molecular spectroscopy. Quantum Cascade Lasers (QCLs) have revolutionized spectroscopic techniques and trace gas analysis due to their unique properties. In spectroscopy, QCLs offer widely tunable, high-powered, and narrow-linewidth radiation across the mid-infrared (MIR) region, enabling precise identification and quantification of molecular species. Utilizing a continuous wave cavity ring-down spectrometer (CW-CRDS) with high resolution, coupled with an external cavity continuous-wave quantum cascade laser (CW-EC-QCL) functioning within the wavenumber interval from 1250 cm⁻¹ to 1333 cm⁻¹ enables spectroscopic examination. This has found applications in various fields namely, Atmospheric Sensing, Biomedical Science, Security and Defense, Environmental Monitoring, Industrial Process Control, Astrophysics and Astronomy. In trace gas analysis, QCLs offer unmatched sensitivity and selectivity. They can detect minuscule concentrations of gases, down to parts per trillion or even lower, making them indispensable in fields where precise gas measurements are paramount. This includes environmental monitoring, medical diagnostics, industrial safety, and scientific research. The versatility and precision of QCL-based spectroscopic techniques continue to drive innovation and advancements in these diverse fields.