Hollow waveguides for the transmission of quantum cascade laser (QCL) energy for spectroscopic applications

Spectroscopy in the long-wave infrared (LWIR) wavelength region (8 to 12 mu m) is useful for detecting trace chemical compounds, such as those indicative of weapons of mass destruction (WMD). To enable the development of field portable systems for anti-proliferation efforts, current spectroscopy systems need to be made more robust, convenient, and practical (e. g., miniaturized). Hollow glass waveguides have been used with a Quantum Cascade Laser source for the delivery of single-mode laser radiation from 9 to 10 mu m. The lowest loss measured for a straight, 484 mu m-bore guide was 0.44 dB/m at 10 mu m. The smallest 300 mu m-bore waveguide transmitted single-mode radiation even while bent to radii less than 30 cm.