High-Efficiency Single Photon Emission from a Silicon T-Center in a Nanobeam

Abstract

Color centers in Si could serve as both efficient quantum emitters and quantum memories with long coherence times in an all-silicon platform. Of the various known color centers, the T-center holds particular promise because it possesses a spin ground state that has long coherence times, but this color center exhibits a long excited state lifetime that results in a low-photon emission rate, requiring methods to extract photon emission with high efficiency. We demonstrate high-efficiency single-photon emission from a single T-center using a nanobeam. The nanobeam efficiently radiates light in a mode that is well-matched to a lensed fiber, enabling us to couple over 70% of the photons in the nanobeam directly into a single-mode fiber. This efficiency enables us to directly demonstrate single-photon emission from the zero-phonon line, which represents the coherent emission from the T-center. Our results represent an important step toward silicon-integrated spin–photon interfaces for quantum computing and quantum networks.

Purcell Enhancement of Silicon W Centers in Circular Bragg Grating Cavities

“…A promising alternative route exploits the integration of isolated atoms into the photonic chip, such as erbium ions or isolated defects acting as artificial atoms. − By embedding one such emitter in a SOI cavity, one expects to tailor its spontaneous emission (SE) thanks to cavity quantum electrodynamics (CQED) effects and to control the single-photon generation process . Concerning color centers in Si, particular attention has been devoted to the G and T centers so far. − Ensembles of G centers have been integrated in a metasurface, micropillars, and Mie resonators to improve light extraction out of silicon, − and efficient collection of single photons has been reported for a T center in a nanobeam . Cavity enhancement of the zero-phonon emission has been demonstrated for an ensemble of G centers in a microring cavity and in a 2D photonic crystal (PhC) cavity for a single G center .…”

Cavity-Enhanced Emission from a Silicon T Center

“…Recent work has successfully isolated single T centers, representing a significant milestone in the field. Subsequent work employed waveguides to isolate single T centers with improved efficiency. , To utilize these promising spin qubit systems for quantum applications, significant challenges must be overcome. In contrast to the G and W centers, the T center has a long excited state lifetime of approximately 1 μs, which makes it a dim emitter.…”

“…The fabrication method and T center implantation approach we used is identical to the one we previously reported for fabrication of bare tapered nanobeams. 21 Figure 1c shows a fabricated nanobeam cavity suspended from the edge of a silicon carrier chip. Figure 1d shows a close-up image of the dashed box in panel c, which contains the cavity region of the device.…”

“…To create the nanobeam structure, we employed a combination of electron beam lithography and transfer print lithography techniques. The fabrication method and T center implantation approach we used is identical to the one we previously reported for fabrication of bare tapered nanobeams Figure c shows a fabricated nanobeam cavity suspended from the edge of a silicon carrier chip.…”

“…From these measurements, we determine a g (2) (0)-corrected continuous-wave count rate of 236.3K cps at the highest pump power. This count rate is >2 orders of magnitude larger than those previously reported using just a nanobeam without a cavity (1090 cps) or nanopillars (325 cps) . These results further reinforce the significant emission enhancement achieved by the cavity.…”