Strain-Tunable Single-Photon Source Based on a Circular Bragg Grating Cavity with Embedded Quantum Dots

We demonstrate a Purcell-enhanced single-photon source realized by the fabrication of a hybrid III–V/dielectric circular Bragg grating cavity directly bonded onto a piezoelectric actuator. Such a kind of photonic system offers the potential for broadband high photon extraction efficiency and spontaneous emission rate enhancement. This device allows for reversible spectral tuning of the embedded quantum dot emitters and pure triggered single-photon generation with g(2)(0) = (1.5 ± 0.05) × 10–3. By applying 18 kV/cm electric filled to the piezosubstrate, we achieve a tuning range larger than 0.78 meV for quantum dots in resonance with the cavity mode. Spontaneous emission lifetimes smaller than 200 ps, in conjunction with a systematic increase of the spontaneous emission rate on resonance with the broadband cavity mode, verify that our device operates deep in the Purcell regime. Our strain-tunable, broadband Purcell-enhanced device represents a crucial building block for scalable quantum technologies.