Tunable Infrared Source by Difference Frequency Mixing Diode lasers and Diode pumped YAG, and Application to Methane Detection

Tremendous potential exists for the application of diode laser sources for high sensitivity detection of atoms and molecules. Some of the obvious applications include pollution monitoring, medical diagnostics, industrial process monitoring, and analytic and atmospheric chemistry applications. Room-temperature, tunable diode laser sources provide the opportunity for constructing compact, transportable instrumentation. Unfortunately the wavelengths of most of the atomic and molecular transitions are not directly accessible with commercially available, room-temperature diode lasers. In particular many of the important molecular transitions are in the mid-infrared spectral region. However, this spectral region is accessible with difference-frequency-generation (DFG) using visible and near-IR lasers.