The objective of this project is to demonstrate the feasibility of room temperature, extended cavity narrowband tunable semiconductor diode laser sources with output wavelengths from 1900nm to 5000nm. We plan to adapt the Littman-Metcalf cavity design to provide the the same tunability, narrow linewidth and reliability with GaInAsSb-AlGaAsSb double heterostructure diodes as with commercially-available high-reliability AlGaAs gain media. We also wish to prove that anti-reflection facet treatments for these diode chips suppress the reflections sufficiently to allow continuous tunability over 100 nm or more and have operating lifetimes of >3000 hours, compatible with space and commercial applications. These lasers will be particularly useful in trace gas detection and environmental monitoring as the wavelengths will overlap relatively strong vibrational absorption bands. The initial goal is to demonstrate the feasibility of GaInAsSbAlGaAsSb extended cavity lasers in the 2000-2300-nm band where index guided gain media are becoming available. This will establish a path towards longer wavelength.The development of single mode tunable laser sources with wavelengths in the 1900-5000 nm range will find commercial application in the areas of trace gas detection, spectroscopy and chemical analysis. These laser sources would complement the already existing line of tunable semiconductor lasers from New Focus. Convenient narrow-band sources with high spectral brightness and continuous tunability in the mid-IR will replace the costly and cumbersome "solutions" that presently exist such as lead-salt diodes.
