Photoionization of Cs (6p 2P3/2) atoms during the operation of a Cs D2 line (852.1 nm: 6p 2P3/2→6s 2S1/2) laser, pumped by free→free transitions of thermal Cs-Ar ground state pairs, has been investigated experimentally and computationally. Photoexcitation of Cs vapor/Ar mixtures through the blue satellite of the D2 transition (peaking at 836.7 nm) selectively populates the 2P3/2 upper laser level by the dissociation of the CsAr excited complex. Comparison of laser output energy data, for instantaneous pump powers up to 3 MW, with the predictions of a numerical model sets an upper bound of 8 × 10−26 cm4 W−1 on the Cs (6p 2P3/2) two photon ionization cross-section at 836.7 nm which corresponds to a single photon cross-section of 2.4 × 10−19 cm2 for a peak pump intensity of 3 MW cm−2.
Applied Physics Letters
J. D. Hewitt, T. J. Houlahan, J. E. Gallagher, D. L. Carroll, A. D. Palla, J. T. Verdeyen, G. P. Perram, J. G. Eden; Role of excited state photoionization in the 852.1 nm Cs laser pumped by Cs-Ar photoassociation. Appl. Phys. Lett. 18 March 2013; 102 (11): 111104. https://doi.org/10.1063/1.4796040