[21p-211A-1~14] 3.6 Ultrashort-pulse and high-intensity lasers

[21p-211A-5] Measurement of spatiotemporal intensity profile of yoked superfluorescence

〇Kenta Kitano¹, Haruka Maeda¹ (1.Aoyama Gakuin Univ.)

Keywords:Nonlinear optics, superfluorescence, four wave mixing

When a dense atomic sample is prepared with a coherent superposition of upper and lower states in a three-level system, the excited atoms quickly decay to the intermediate state with an emission of a superfluorescent pulse, which can induce the transition between the intermediate and ground states, resulting in a highly directional emission. This coherent interplay between the upper and lower transitions is called yoked superfluorescence(YSF). We investigated the YSF from atomic vapor of rubidium(Rb) by driving the 5S-5D two-photon transition with an ultrashort laser pulse. By increasing the pump-pulse power beyond the saturation intensity, the spatial profile of the emission from the lower transition component of the YSF periodically changed between a central bright spot and a ring-shaped radial profile. The observed behavior was successfully explained by a nonlinear response of Rb atoms to the pump field.