Blue and Infrared Stimulated Emission from Alkali Vapors Pumped through Two-photon Absorption
The 5 2D3/2, 5 2D5/2, and 7 2S1/2 states of rubidium and the 7 2D3/2, 7 2D5/2, and 9 2S1/2 states of cesium were populated at low pressure by two photon excitation using a pulsed dye laser. Blue beams from the Rb 6 2P3/2, 1/2–5 2S1/2 and Cs 7 2P3/2, 1/2–6 2S1/2 transitions were observed. In addition, infrared beams were observed arising directly from the pumped 2D states, establishing a collisionless cascade mechanism. Threshold is modest at about 0.3 mJ/pulse or 2×105 W/cm2. Slope efficiencies increase dramatically with alkali concentration and peak at 0.4%, with considerable opportunity for improvement. This versatile system might find applications in both underwater communications and for infrared counter measures.
Applied Physics B
Sulham, C.V., Pitz, G.A. & Perram, G.P. Blue and infrared stimulated emission from alkali vapors pumped through two-photon absorption. Appl. Phys. B 101, 57–63 (2010). https://doi.org/10.1007/s00340-010-4015-9