Optomechanical single photon frequency division multiplexing

Here we report on the implementation of a hybrid nonlinear optomechanical scheme to generate frequency multiplexed of single photons from a single quantum dot. To this end, the excitonic optical transition of a single semiconductor quantum dot (QD) is coherently driven by a laser with a frequency of approximately 330THz and simultaneously dynamically strained by a surface acoustic wave (SAW) in the low GHz regime. The coherent optomechanical interaction caused by the QD mixes optical and acoustic frequencies, resulting in the generation of a frequency comb. Thus the collected resonance fluorescence signal, consisting of single photons, is emitted into these frequency bins, precisely split by the frequency ω_SAW of the SAW.
Furthermore the nonlinear interaction between two mutually coherent SAWs with frequencies ω_SAW and 2ω_SAW allow for the intensity modulation of certain teeth of the comb. The probability of a single photon being emitted in a given frequency bin can be programed, by the relative phase between the two SAWs. Introducing a frequency detuning of 50μHz between the two SAWs an intensity modulation of the teeth of the frequency comb with a period of approximately 5½ hours can directly be observed, verifying the extraordinary stability of our scheme.