A novel 2 μm, frequency conversion based, laser transmitter for CO 2 DIAL

We report on a novel 2 μm laser transmitter for CO 2 DIAL, based on a nanosecond parametric master oscillator-power amplifier architecture. The master oscillator is an entangled-cavity, doubly resonant, optical parametric oscillator, based on a type-II periodically poled Lithium Niobate nonlinear crystal. This device provides single-longitudinal-mode radiation, with a high frequency stability and high beam quality, with no need of an additional seeding source. The 2.05 μm signal emission is amplified by multi-stage parametric amplifiers to generate more than 10 mJ. After amplification, both the spectral purity and beam quality are maintained: we demonstrate single-longitudinal-mode emission with a frequency stability better than 3 MHz rms, within a nearly diffraction limited beam, with a M 2 quality factor close to 1.5. The unique performances of this parametric architecture make this device a relevant transmitter for CO 2 differential-absorption LIDAR. Such approach could be readily duplicated for the detection of other greenhouse gases.