Light from Silicon: A Bullseye for Quantum Photonics

Scalable quantum photonic technologies require compact, efficient, and on-chip single-photon sources to achieve quantized light. Silicon is an especially attractive platform because it supports mature nanofabrication and is fully compatible with established photonic-device manufacturing. In the image, a scanning electron microscopy (SEM) image of a nanoscale silicon circular Bragg grating or bullseye cavity is shown, which is not visible to the naked human eye, consisting of an engineered light-emitting defect known as G-center single-photon source created beneath the bullseye cavity for quantum device application. This research focuses on optimizing the silicon bullseye cavity, integrated with the G-center single-photon source to emit quantized photons in the telecom O-band range by trapping an electron in it. This wavelength range is particularly important because it enables very low transmission loss in optical communication systems. Using simulation-based analysis, this study examines how the bullseye cavity geometry and emitter properties affect key performance metrics, including optical confinement, emission enhancement, and photon extraction efficiency. Additional structural strategies were also investigated to further strengthen light-matter interaction and improve overall integrated quantum device performance.