Single frequency, narrow linewidth 935nm laser source for high-altitude water vapor LiDAR

We have demonstrated a single frequency, narrow linewidth OPO source operating at 935 nm with an output energy of greater than 28 mJ and M² of 1.7x1.2. The 935 nm conversion efficiency is 31.4% with a threshold of 42 mJ and a slope efficiency of 60%. The photon conversion efficiency is >55%. The OPO consists of two 25 mm long LBO crystals in a rectangular ring cavity, pumped by up-to 90 mJ at 532 nm from a 150 Hz repetition rate, frequency-doubled Nd:YAG laser. The Nd:YAG pump laser is also single frequency with the green output tuned to an Iodine line. The OPO is seeded by a SOA amplified 935 nm DBR laser diode source and the cavity is locked to the seed wavelength using the PDH technique with a PZT actuated sliding wedge to adjust the cavity length. Measured linewidth is 90 MHz. This demonstrated laser source (pump laser and OPO) is currently being designed for 200 Hz operation and packaging and integration into the NASA HALO instrument to be flown aboard the NASA ER-2 for making high altitude atmospheric water vapor and aerosol measurements.