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 introduce a van der Waals platform comprising strain-engineered bilayer WSe ₂ quantum emitters, integrated on multimode WS ₂ waveguides with grating couplers, enabling efficient on-chip quantum light sources. The emitters exhibit bright, highly polarised emission that couples efficiently into WS ₂ waveguides. Under p-shell excitation, we observe high-purity, waveguide-coupled single-photon emission, measured using both an off-chip Hanbury Brown-Twiss configuration (g ⁽²⁾ (0) = 0.003 ^+0.030 _-0.003 ) and an on-chip configuration (g ⁽²⁾ (0) = 0.076±0.023). For a single output, the out-coupled single-photon count rate at the first lens reaches approximately 299 kHz under continuous-wave p-shell excitation, corresponding to an estimated waveguide-coupled rate of 1.59 MHz. These results demonstrate an efficient, integrated single-photon source and establish a pathway toward scalable photonic quantum information processing centred around nanoengineered van der Waals materials.