Silicon is the most scalable optoelectronic material but has suffered from its inability to generate directly and efficiently classical or quantum light on-chip. Scaling and integration are the most fundamental challenges facing quantum science and technology. We report an all-silicon quantum light source based on a single atomic emissive center embedded in a silicon-based nanophotonic cavity. We observe a more than 30-fold enhancement of luminescence, a near-unity atom-cavity coupling efficiency, and an 8-fold acceleration of the emission from the all-silicon quantum emissive center. Our work opens immediate avenues for large-scale integrated cavity quantum electrodynamics and quantum light-matter interfaces with applications in quantum communication and networking, sensing, imaging, and computing.

We implanted ultralow doses (2×1011cm−2) of antimony ions (Sb121) into isotopically enriched silicon (Si28) and find high degrees of electrical activation and low levels of dopant diffusion after rapid thermal annealing. Pulsed electron spin resonance shows that spin echo decay is sensitive to the dopant depths, and the interface quality. At 5.2K, a spin decoherence time, T2, of 0.3ms is found for profiles peaking 50nm below a Si∕SiO2 interface, increasing to 0.75ms when the surface is passivated with hydrogen. These measurements provide benchmark data for the development of devices in which quantum information is encoded in donor electron spins.

We report electron spin resonance measurements of donors in silicon at millikelvin temperatures using a superconducting LC planar micro-resonator and a Josephson parametric amplifier. The resonator includes a nanowire inductor, defining a femtoliter detection volume. Due to strain in the substrate, the donor resonance lines are heavily broadened. Single-spin to photon coupling strengths up to $\sim 3\hspace{0.17em}\text{kHz}$ are observed. The single shot sensitivity is $120\hspace{0.17em}\pm \hspace{0.17em}24$ spins/Hahn echo, corresponding to $\approx 12\pm 3$ spins $/\sqrt{\text{Hz}}$ for repeated acquisition.

Magnetic Vortex Acceleration (MVA) from near critical density targets is one of the promising schemes of laser-driven ion acceleration. 3D particle-in-cell simulations are used to explore a more extensive laser-target parameter space than previously reported in the literature as well as to study the laser pulse coupling to the target, the structure of the fields, and the properties of the accelerated ion beam in the MVA scheme. The efficiency of acceleration depends on the coupling of the laser energy to the self-generated channel in the target. The accelerated proton beams demonstrate a high level of collimation with achromatic angular divergence, and carry a significant amount of charge. For petawatt-class lasers, this acceleration regime provides a favorable scaling of the maximum ion energy with the laser power for the optimized interaction parameters. The megatesla-level magnetic fields generated by the laser-driven coaxial plasma structure in the target are a prerequisite for accelerating protons to the energy of several hundred mega-electron-volts.

Silicon-based quantum emitters are candidates for large-scale qubit integration due to their single-photon emission properties and potential for spin-photon interfaces with long spin coherence times. Here, we demonstrate local writing and erasing of selected light-emitting defects using femtosecond laser pulses in combination with hydrogen-based defect activation and passivation at a single center level. By choosing forming gas (N₂/H₂) during thermal annealing of carbon-implanted silicon, we can select the formation of a series of hydrogen and carbon-related quantum emitters, including T and C_i centers while passivating the more common G-centers. The C_i center is a telecom S-band emitter with promising optical and spin properties that consists of a single interstitial carbon atom in the silicon lattice. Density functional theory calculations show that the C_i center brightness is enhanced by several orders of magnitude in the presence of hydrogen. Fs-laser pulses locally affect the passivation or activation of quantum emitters with hydrogen for programmable formation of selected quantum emitters.

We have measured the electrically detected magnetic resonance of donor-doped silicon field-effect transistors in resonant $X$- (9.7 GHz) and $W$-band (94 GHz) microwave cavities. The two-dimensional electron gas resonance signal increases by 2 orders of magnitude from $X$ to $W$ band, while the donor resonance signals are enhanced by over 1 order of magnitude. Bolometric effects and spin-dependent scattering are inconsistent with the observations. We propose that polarization transfer from the donor to the two-dimensional electron gas is the main mechanism giving rise to the spin resonance signals.