Two-Photon Laser

Abstract
We have demonstrated a pulsed two-photon laser at the transition 3dD22sS2 of atomic Li (frequency ω31) by (i) generation of a coherent light beam at ωx, stimulated by light pulses at ω1=ω31ωx, and (ii) single-pass amplification of injected light at ω3=ω312.