Near-infrared (769–770 nm) K atomic laser optically pumped through KXe excimer intermediate states

Photopumping of K/Xe vapor mixtures over a continuous spectral region >1.2 THz (>40 cm^-1) in breadth yields lasing on the D₁ line of atomic potassium (4<i>p</i>²<i>P</i>_1/2 → 4<i>s</i>²<i>S</i>_1/2) by populating the dissociative B²<i>Σ</i>1/2+ or weakly bound A²Π_3/2 states of the KXe excimer molecule. Subsequent dissociation of the excited molecule populates the 4<i>p</i>²<i>P</i>_3/2 and 4<i>p</i>²<i>P</i>_1/2 levels of the K atom, the latter of which is the upper level for the 769.9 nm resonance line laser. Lasing over ∼60% of the 57.7 cm^-1 gap lying between the spin-orbit split 4<i>p</i>²<i>P</i>_3/2 - 4<i>p</i>²<i>P</i>_1/2 states has been achieved, and single-pulse energies up to ∼35 µJ have been obtained when pumping the K/Xe mixture in the vicinity of the D₂ line (766.5 nm) in a single-pass pumping configuration of the resonator. The quantum efficiency (>99%) and broad pump-acceptance bandwidth afforded by the KXe excimer lend this hybrid atomic/molecular photodissociation laser to pumping with free-running semiconductor laser arrays.