Picosecond multiphoton STIRAP detection of gas phase species: a test with sodium
Jerald B. Johnson, Susan Davis Allen, Daniel R. Britton +4 more
Laser detection technologies offer obvious benefits for the standoff detection of hazardous or energetic materials where safe detection at a distance is the goal. Of the many optical standoff detection methods available, multiphoton fluorescence techniques have been studied less extensively. Multiphoton fluorescence allows high selectivity relative to the background while preserving the larger signal of laser induced fluorescence (LIF). Using sodium vapor as a test system, we demonstrate that stimulated Raman adiabatic passage (STIRAP) is capable of providing more than a factor of ten improvement in population transfer efficiency to the final state when compared to stimulated emission pumping (SEP). The two sodium transitions used are the 3p (2P1/2) ← 3s (2S1/2) and 5s (2S1/2) ← 3p (2P1/2). The light used to couple the states was produced with two synchronously pumped OPG/OPAs pumped by the 355 nm light from a picosecond tripled Nd:YAG.
Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 21, 2009•4 citations