Cascaded single-photon emission from the Mollow triplet sidebands of a quantum dot

Emission from a resonantly excited quantum emitter is a fascinating research topic within the field of quantum optics and is a useful source for different types of quantum light fields. The resonance spectrum consists of a single spectral line that develops into a triplet above saturation of the quantum emitter1,2,3. The three closely spaced photon channels from the resonance fluorescence have different photon statistical signatures4. We present a detailed photon statistics analysis of the resonance fluorescence emission triplet from a solid-state-based artificial atom, that is, a semiconductor quantum dot. The photon correlation measurements demonstrate both ‘single’ and ‘cascaded’ photon emission from the Mollow triplet sidebands5. The bright and narrow sideband emission (5.9 × 106 photons per second into the first lens) can be conveniently frequency-tuned by laser detuning over 15 times its linewidth (Δv ≈ 1.0 GHz). These unique properties make the Mollow triplet sideband emission a valuable light source for quantum light spectroscopy and quantum information applications, for example.