Joule Level Double-pulsed Ho:Tm:LuLF Master-Oscillator-Power-Amplifier (MOPA) for Potential Spaceborne Lidar Applications

摘要

Spaceborne coherent Doppler wind lidars and CO_2 Differential Absorption Lidars (DIALs) at eye-safe 2-μm spectral range have been proposed for several years for accurate global wind and carbon-oxide concentration profiling measurement. These lidar systems require Joule level laser pulse energy from laser transmitter and high efficiency. In this paper, we report a diode-pumped Ho:Tm:LuLF Master-Oscillator-Power-Amplifier (MOPA) developed to demonstrate Joule level output pulse energy. The MOPA consists of one master oscillator and two power amplifiers. The master oscillator was Q-switched and can be operated at single pulse mode or double pulse mode respectively. The single pulse operation is used for a coherent Doppler wind lidar and the double pulse operation for a CO_2 Differential Absorption Lidar (DIAL). The output pulse energy of the master oscillator is 115 mJ for the single pulse operation and 186 mJ for the double pulse operation. To extract more energy from the pumping pulses and increase the efficiency of the MOPA, the first amplifier was set at a double pass configuration. The second amplifier was set at a single pass configuration to avoid the damage problem of the Ho:Tm:LuLF laser rod. Total output pulse energy of 0.63 J with an optical efficiency of 4.1% for single pulse operation and 1.05 J with an optical efficiency of 6.9 % for double pulse operation were demonstrated.