Dresden 2026 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 26: Poster II

HL 26.30: Poster

Wednesday, March 11, 2026, 09:30–11:30, P1

Double Gaussian Defect Cavity Design for Semiconductor Based Entangled Photon Sources — •Xian Zheng, Fei Ding, and MIchael Zopf — Institute of Solid State Physics, Leibniz University of Hannover, Appelstr. 2, 30167 Hannover, Germany

Polarization-entangled photon pairs are essential resources for quantum communication and quantum networks, enabling protocols such as quantum key distribution, teleportation, and entanglement swapping. However, simultaneously controlling cavity spectrum, field profile, and balanced coupling to multiple radiative transitions in a solid-state emitter remains challenging. In this work, we design a double-Gaussian defect cavity as a flexible platform to engineer semiconductor quantum-dot entangled photon sources. Two Gaussian-shaped, microsphere-like thickness modulations are embedded inside a DBR cavity and sculpt the axial and lateral field distributions, providing independent knobs, such as cavity height and defect width, to simultaneously tune the cavity resonance close to emission lines, such as biexciton and exciton emission and optimize the emission wavelength. Using FDTD simulations and time-domain exponential decay fitting, we extract the quality factor, mode volume, and Purcell enhancement, and quantify their dependence on the geometric parameters. The resulting design framework provides practical guidelines for tailoring cavity*quantum-dot coupling in double-Gaussian defect geometries and supports the development of bright, on-demand entangled photon sources suitable for future integrated quantum-network architectures.

Keywords: Entanlgled photon source; Double guassian defect cavity