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Coherence brightened laser source for atmospheric remote sensing |
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| Authors: | Andrew J Traverso Rodrigo Sanchez-Gonzalez Luqi Yuan Kai Wang Dmitri V Voronine Aleksei M Zheltikov Yuri Rostovtsev Vladimir A Sautenkov Alexei V Sokolov Simon W North Marlan O Scully |
| Institution: | aTexas A&M University, College Station, TX 77843; ;bBaylor University, Waco, TX 76798; ;cMoscow State University, Moscow 119992 Russia; ;dUniversity of North Texas, Denton, TX 76203; and ;ePrinceton University, Princeton, NJ 08544 |
| Abstract: | We have studied coherent emission from ambient air and demonstrated efficient generation of laser-like beams directed both forward and backward with respect to a nanosecond ultraviolet pumping laser beam. The generated optical gain is a result of two-photon photolysis of atmospheric O2, followed by two-photon excitation of atomic oxygen. We have analyzed the temporal shapes of the emitted pulses and have observed very short duration intensity spikes as well as a large Rabi frequency that corresponds to the emitted field. Our results suggest that the emission process exhibits nonadiabatic atomic coherence, which is similar in nature to Dicke superradiance where atomic coherence is large and can be contrasted with ordinary lasing where atomic coherence is negligible. This atomic coherence in oxygen adds insight to the optical emission physics and holds promise for remote sensing techniques employing nonlinear spectroscopy. |
| Keywords: | nonadiabatic coherence oxygen laser coherence brightening stand-off detection intensity spiking |