Integrated on-chip quantum light sources on a van der Waals platform

Scalable photonic quantum information technologies require a platform combining quantum light sources, waveguides, and detectors on a single chip. Here, we demonstrate integrated quantum light sources based on strain-engineered bilayer WSe2 quantum emitters coupled to multimode WS2 waveguides with grating couplers. These emitters exhibit bright, highly polarised emission that couples efficiently into WS2 waveguides. Under discrete-state excitation, we observe high-purity, waveguide-coupled single-photon emission, measured using both single-port and cross-correlated, multi-port photon streams, yielding $${g}^{(2)}(0)=0.00{3}_{-0.003}^{+0.030}$$ and g(2)(0) = 0.076 ± 0.023, respectively. For a single output, the out-coupled single-photon count rate at the first lens reaches approximately 357 kHz under continuous-wave discrete-state excitation, corresponding to an estimated minimum waveguide-coupled rate of 1.68 MHz. These results demonstrate an efficient, integrated single-photon source based on van der Waals materials, representing a step towards scalable integrated quantum photonics. Integrating quantum emitters with on chip photonic circuits remains a challenge for van der Waals materials. Here, the authors couple strain induced WSe2 quantum emitters to WS2 waveguides, demonstrating high purity waveguide coupled single photon emission in an all van der Waals photonic platform.