A Lithographically Defined Quantum Dot with Simultaneous Sub-Wavelength Confinement of Light

Deterministic fabrication of quantum dots in optical devices is a long-standing challenge for future integrated photonics and electronics applications. Current approaches typically rely on alignment or transfer techniques [1], but the scalability is limited by the unavoidable introduction of uncertainty in both the geometry and the positioning of the dots. In this work, we present a lithographically defined quantum dot integrated with a nanostructured optical cavity with sub-wavelength confinement of light. The design is based on an optical bowtie cavity [2] in an InP dielectric membrane with an embedded InGaAsP quantum well. By modifying the central bowtie geometry, the structure can be made to support localized electron-hole states in the region of the optical hotspot. The concept is illustrated in Fig. 1.