Development of a frequency-locked Er:YAG laser for methane and water vapor DIAL

Information on the spatial distributions of methane and vertical profiles of water vapor are essential in better understanding the carbon cycle, atmospheric dynamics and their roles in climate change and numerical weather prediction. Fibertek is developing Er:YAG laser technology for differential absorption lidar (DIAL) that can simultaneously access methane (1645.55 nm) and water vapor (822.92 nm) absorption lines. In this paper we will present data on a hardened 1kHz single-frequency oscillator that is frequency doubled to produce 3 mJ at 823 nm and 3 mJ at 1645 nm for airborne DIAL on the NASA Langley HALO platform. Status and challenges addressed in power scaling experiments on the Er:YAG system for a space-based mission will also be presented. Finally, we will present small signal gain measurements in Er:YAG which show the benefits of low temperature operation for power scaling.