Nanoscale Positioning and In Situ Enhancement of Single G Center in Silicon Using a Fluorescence-Localization Technique

Silicon-based semiconductor nanofabrication technology has achieved a remarkable level of sophistication and maturity, and color centers in silicon naturally inherit this advantage. Besides, their emissions appear in telecommunication bands, which makes them play a crucial role in the construction of a quantum network. To address the challenge of weak spontaneous emission, different optical cavities are fabricated to enhance the emission rate. However, the relative location between cavity and emitter is random, which greatly reduces the success probability of enhancement. Here, we report on a fluorescence-localization technique (FLT) for precisely locating a single G center in silicon and embedding it in the center of a circular Bragg grating cavity in situ, achieving 240-times improvement of the success probability. We observe a 30-fold enhancement of luminescence, 2.5-fold acceleration of the emission from a single G center, corresponding to a Purcell factor exceeding 11. Our findings pave the way for large-scale integration of quantum light sources.