Compact Broad-Band Wavelength-Agile Mid-Infrared Semiconductor Lasers for Spectroscopic Sensing

摘要

This report presents advances in mid-infrared (IR) lasers, photonics, and system applications. Compact mid-infrared, broadly tunable lasers have been developed and demonstrated for wavelength from 3 to 9.6 micrometers. Both Sb and InP quantum cascades were used. Advanced concepts of tunable, two-segment lasers and off-band, surface-emitting Bragg-grating-coupled lasers were demonstrated with broad, continuous tunability and fast wavelength modulation. Other advanced mid-IR photonics include optical preamplifiers with a tunable Bragg for an advanced receiver in remote sensing such as lidars. This program has verified key basic scientific aspects of the proposed tunable laser concept and design, which can eventually be transferred to manufacturing and development. This mid-IR tunable laser technology is essential for spectroscopic chemical warfare agent detection. The advanced laser technology allows applications such as wavelength modulation spectroscopy (WMS), which was demonstrated with gas absorption spectroscopy. For advanced system applications, novel spectral imaging based on WMS was developed and demonstrated to map spatial distribution of a gas with background-clutter rejection. More general multi-spectral, mid-IR spectral imaging techniques based on these lasers have shown potential applications in chemical and biological target recognition based on spectral signatures. A list of 38 journal articles, proceedings papers, and meeting papers is included.