1.65 µm Er:YAG hybrid fibered/bulk emitter for CH4 differential absorption lidar

A new Differential Absorption Lidar (DIAL) for atmospheric methane (CH4) profile measurement is under development at LMD. The lidar emitter is a new hybrid fibered/bulk Er:YAG laser. Two Erbium doped fiber lasers at 1532 nm are used to pump an Er:YAG rod in a ring cavity. The pulsed laser is sequentially injection-seeded by 2 fiber coupled CW Distributed Feedback (DFB) laser diodes On and Off respectively in the center of the methane line triplet at 1645.55 nm and out of at 1645.3 nm. It delivers dual On/Off 8 mJ/ 300 ns pulses at a repetition frequency of 1 kHz but other configuration can also be chosen. In this paper, we will present the objectives of this work, describe the experimental set-up and the laser performances with respect to power efficiency, beam quality, spectral purity and stability.