Single-particle photoluminescence from cadmium selenide quantum dots fabricated via laser ablation in superfluid helium

We fabricated cadmium selenide nanoparticles using a pulsed laser-ablation scheme in superfluid helium. The fabricated nanoparticles showed photoluminescence blinking and a clear blueshifted emission whose linewidth was nearly equal to the homogeneous linewidth. These results demonstrate that our method can prepare quantum dots with a sharp resonance directly in superfluid helium, enabling the further implementation of resonant optical manipulation and optical trapping in cryogenic systems.