Answers are grounded in this paper and cite their sources.
Resonant two-photon pumping in the Cs 6s2S-7s2S transition has been used for 2.9 μm to 4550 Å image up-conversion. A power conversion efficiency of 20% with 1000 resolvable spots was achieved using a pump power of 8 kW. The pumping laser, Nd : lanthanum berylate, has a natural two-photon coincidence with the Cs 6s2S-7s2S transition.
No takes yet. Share an insight, caveat, or question.
Stappaerts et al. (1976) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: