Atomic Lines of Amplified Spontaneous Emission during Optical Pumping of Yb by KrF*-Laser Radiation

Abstract

Results on quasi-resonant optical pumping of Yb vapors by KrF*-laser radiation (λ_p = 248 nm) are presented. The radiation was converted to the visible range to be available for study. Strong lines of amplified spontaneous emission are detected. These lines are due to transitions between the groups of even (6s5d¹D₂, 6s6d³D_{1, 2, 3}) and odd Yb levels (6s6p¹P₁⁰, 6s6p³P_0,1,2⁰). Coherent radiation is detected at Yb resonance lines with λ = 398.8 and 555.6 nm, which are caused, respectively, by the 6s6p¹P₁⁰ → 6s6s¹S₀ and 6s6p³P₁⁰ → 6s6s¹S₀ transitions in the Yb atom. A sequence of processes that lead to the formation of inversion at the Yb atomic transitions is qualitatively examined.