Cs 894.3 nm laser pumped by photoassociation of Cs-Kr pairs: Excitation of the Cs D2 blue and red satellites

Lasing on the D₁ transition (6²P_1/2→ 6²S_1/2) of Cs has been observed by photoassociating Cs-Kr atomic pairs with a tunable, pulsed dye laser. Pumping of the blue or red satellites of the Cs D2 line (6²P_3/2⇆6 ²S_1/2), peaking at ∼841.1 nm and ∼853 nm (respectively) in Cs/Kr/C₂H₆ gas mixtures, provides a photodissociation laser in which the CsKr excimer parent molecule is not, at any point in the pumping process, in a bound electronic state. Relative to the absorbed pump pulse energy, laser slope efficiencies ≳5% have been measured when the Cs number density is in the range of 5 x 10¹⁴-1.5 x 10 ¹⁵ cm^-3 and the pump wavelength is 841.1 nm. Direct photoexcitation of the Cs 6²P_3/2 state at 852.1 nm under these conditions is a less efficient pathway for pumping the 894.3 nm laser, presumably as a result of competing nonlinear optical processes such as 1+2 resonantly enhanced multiphoton ionization of the alkali atom.