Integration of a single photon source with a photonic waveguide

The integration of a single photon source based on a solid-state emitter with a photonic structure remains to this day a challenging operation. It is however of prime importance to do so for quantum technologies where single photon sources constitute building blocks for many technologies and in particular for quantum photonics. In this work, we demonstrate a new way of integrating a single photon source, in our case made of a single colloidal semiconductor nanocrystal, with a photonic structure made of a glass waveguide obtained by the ion-exchange technique. Using surface functionalisation and a secondary waveguide of titanium dioxide made by electron-beam lithography, we manage to couple single photons coming from the emitter to the optical waveguide. We observe that the single photon character is preserved and demonstrates a Purcell factor of 1.2. Even though this configuration is not an optimum one, a coupling efficiency of more than 25 % is expected, compared to around 1 to 2 % we obtain for simply positioning the nanocrystal on top of the waveguide alone. The optical waveguide is then pigtailed to an optical fibre to demonstrate a first proof of principle of an integrated single photon source at room temperature.