Potential NASA Commercial Applications: The tunable laser technology developed in this project can be used to support a wide variety of commercial products. Leak detection alone is a huge industry hampered by the lack of such a portable laser source. Residential natural gas companies routinely search for leaks in distribution systems using very expensive methods (including trucks manned with funnel suction lines and spectroscopic equipment). The same situation exists at supplier levels where gas transmission, production, and storage facilities use enormous amounts of resources detecting leaks. Low cost, portable leak monitors, enabled by this source technology, would reduce the cost of facility ownership. Finally, the cost benefits that come with volume opportunities associated with semiconductor-based lasers could lead to devices with costs easily below $1000 per unit in large volumes and hence, portable sensors at unit costs below $2500. This is well below a critical price point in the chemical sensor industry. Potential Non-NASA Commercial Applications: The tunable source developed under this program could be used in LIDAR instruments and components that are required by NASA to support remote sensing measurements for future earth science missions. NASA particularly needs advanced components for in-situ gas measurements using tunable laser spectrometers in circumstances where available platforms such as aircraft, balloons, surface and entry probes, and landed rovers, present severe limitations on resources. Tunable laser absorption spectroscopy is a simple measurement technique known for its high sensitivity and specificity. For instance, tunable laser spectroscopy can measure the CH4 abundance down to 10 parts in 1E12 with preconcentration and to 1 ppbv without preconcentration. Measurement of the isotopic ratio 13C/12C in CH4 will help assess the biogenic origin of CH4 on a planet like Mars. Also important are laser sources for remote measurements of carbon-based trace gases (CO2, CH4, C2H6, and CO) from aircraft and spacecraft operating to nadir using the earth¡¦s surface as a target, as well as for profiling measurements from the ground using atmospheric backscatter. The same laser source developed for these NASA requirements would also be a very attractive spectroscopy product for the scientific community.