Performance Characteristics of a Compact Widely Tunable External Cavity Quantum Cascade Laser

Daylight Solutions is developing broadly tunable, external cavity quantum cascade lasers (EC-QCLs) for gas sensing instrumentation. Recent efforts at Daylight Solutions yielded the world's first miniature room temperature EC-QCLs comprising a 15 mm long optical cavity, miniature grating tuning mechanism and integrated current and temperature controls. The laser operates in the 4.5-10.5μm spectral region with a scanning range up to 100 cm-1. Spectral resolution is better than 1 cm-1 and scanning rate is faster than 1 second. In addition to the relative simplicity and ruggedness of the opto-mechanical design, the laser also features low power consumption, does not require precise current and temperature control, and operates at room temperature with convective cooling. The prototype QCL-based acetone sensor has shown a sensitivity of 100 ppb. In parallel, a continuously tunable CW broadly external cavity QCL laser prototype was developed. The CW laser performance was evaluated by recording ammonia spectrum.