Mainz 2026 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 28: Poster – Quantum Optics

Q 28.9: Poster

Dienstag, 3. März 2026, 17:00–19:00, Philo 2. OG

Design and simulation of circular Bragg grating cavities for enhanced emission and spin readout of silicon C centers — •Junchun Yang¹, Alessandro Puddu^1,2, Shuyu Wen², Sourav Dev¹, Shengqiang Zhou², Yonder Berencén², and Kambiz Jamshidi¹ — ¹TU Dresden, Dresden, German — ²Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany

Color centers are optically addressable atomic-scale defects in solid-state hosts that enable the coherent control of individual spins and the generation of quantum light. Among them, silicon-based color centers are particularly attractive owing to technological maturity, CMOS compatibility, and scalability. Recently, we demonstrated optically detected magnetic resonance (ODMR) of an ensemble of silicon C centers, revealing the energy-level structure and spin-selective optical transitions. Here, we aim to enhance both the emission rate and photon collection efficiency of the silicon C center through integration with a photonic cavity. A circular Bragg gratings (CBG) cavity provides a moderate Purcell factor while its rotational symmetry ensures efficient upward coupling for any in-plane dipole. Additionally, the broad cavity linewidth enables spectral overlap without post-fabrication tuning. In this work, we use finite-difference time-domain (FDTD) simulations in Lumerical to design a CBG cavity, achieving a theoretical Purcell enhancement of 11 and a collection efficiency of 40%.

Keywords: Color center; Silicon; Circular Bragg gratings; FDTD simulations