We use a laser-driven single (In,Ga)As quantum dot (QD) in the dressed-state regime of resonance fluorescence (T=4K) to observe the four D1-transition lines of alkali atomic cesium (Cs) vapor at room temperature. We tune the frequency of the dressing continuous-wave laser in the vicinity of the bare QD resonance ∼335.116THz (∼894.592nm) at constant excitation power and thereby controllably tune the center and side channel frequencies of the probe light, i.e., the Mollow triplet. Resonances between individual QD Mollow triplet lines and the atomic hyperfine-split transitions are clearly identified in the Cs absorption spectrum. Our results show that narrow-band (In,Ga)As QD resonance fluorescence (RF) is suitable to optically address individual transitions of the D1 quadruplet without applying magnetic field or electric field tuning.
Publication: Spectroscopy of the D1 transition of cesium by dressed-state resonance fluorescence from a single (In,Ga)As/GaAs quantum dot
S. M. Ulrich, S. Weiler, M. Oster, M. Jetter, A. Urvoy, R. Löw, and P. Michler 
Phys. Rev. B 90, 125310 – Published 18 September 2014
Contact person: Prof. Peter Michler