RESUMEN
Optical manipulation of quantum systems requires stable laser sources able to produce complex waveforms over a large frequency range. In the visible region, such waveforms can be generated using an acousto-optic modulator driven by an arbitrary waveform generator, but these suffer from a limited tuning range typically of a few tens of MHz. Visible-range electro-optic modulators are an alternative option offering a larger modulation bandwidth, however they have limited output power which drastically restricts the scalability of quantum applications. There is currently no architecture able to perform phase-stabilized waveforms over several GHz in the visible or near infrared region while providing sufficient optical power for quantum applications. Here we propose and develop a modulation and frequency conversion set-up able to deliver optical waveforms over a large frequency range, with a high spurious extinction ratio, scalable to the entire visible/near infrared region with high optical power. The optical waveforms are first generated at telecom wavelength and then converted to the emitter wavelength through a sum frequency generation process. By adapting the pump laser frequency, the optical waveforms can be tuned to interact with a broad range of optical quantum emitters or qubits such as alkali atoms, trapped ions, rare earth ions, or fluorescent defects in solid-state matrices. Using this architecture, we were able to detect and study a single erbium ion in a nanoparticle. We also generated high bandwidth signals at 606 nm, which would enable frequency multiplexing of on-demand read-out Pr3+:Y2SiO5 quantum memories.
RESUMEN
Integrating atomic quantum memories based on color centers in diamond with on-chip photonic devices would enable entanglement distribution over long distances. However, efforts towards integration have been challenging because color centers can be highly sensitive to their environment, and their properties degrade in nanofabricated structures. Here, we describe a heterogeneously integrated, on-chip, III-V diamond platform designed for neutral silicon vacancy (SiV0) centers in diamond that circumvents the need for etching the diamond substrate. Through evanescent coupling to SiV0 centers near the surface of diamond, the platform will enable Purcell enhancement of SiV0 emission and efficient frequency conversion to the telecommunication C-band. The proposed structures can be realized with readily available fabrication techniques.
RESUMEN
Atomic and atomlike defects in the solid state are widely explored for quantum computers, networks, and sensors. Rare earth ions are an attractive class of atomic defects that feature narrow spin and optical transitions that are isolated from the host crystal, allowing incorporation into a wide range of materials. However, the realization of long electronic spin coherence times is hampered by magnetic noise from abundant nuclear spins in the most widely studied host crystals. Here, we demonstrate that Er3+ ions can be introduced via ion implantation into TiO2, a host crystal that has not been studied extensively for rare earth ions and has a low natural abundance of nuclear spins. We observe efficient incorporation of the implanted Er3+ into the Ti4+ site (>50% yield) and measure narrow inhomogeneous spin and optical line widths (20 and 460 MHz, respectively) that are comparable to bulk-doped crystalline hosts for Er3+. This work demonstrates that ion implantation is a viable path to studying rare earth ions in new hosts and is a significant step toward realizing individually addressed rare earth ions with long spin coherence times for quantum technologies.
RESUMEN
Solid-state electronic spins are extensively studied in quantum information science, as their large magnetic moments offer fast operations for computing1 and communication2-4, and high sensitivity for sensing5. However, electronic spins are more sensitive to magnetic noise, but engineering of their spectroscopic properties, for example, using clock transitions and isotopic engineering, can yield remarkable spin coherence times, as for electronic spins in GaAs6, donors in silicon7-11 and vacancy centres in diamond12,13. Here we demonstrate simultaneously induced clock transitions for both microwave and optical domains in an isotopically purified 171Yb3+:Y2SiO5 crystal, reaching coherence times of greater than 100 µs and 1 ms in the optical and microwave domains, respectively. This effect is due to the highly anisotropic hyperfine interaction, which makes each electronic-nuclear state an entangled Bell state. Our results underline the potential of 171Yb3+:Y2SiO5 for quantum processing applications relying on both optical and spin manipulation, such as optical quantum memories4,14, microwave-to-optical quantum transducers15,16, and single-spin detection17, while they should also be observable in a range of different materials with anisotropic hyperfine interactions.
RESUMEN
Efficient and reversible optical to microwave transducers are required for entanglement transfer between superconducting qubits and light in quantum networks. Rare-earth-doped crystals with narrow optical and spin transitions are a promising system for enabling these devices. Current resonant transduction approaches use ground-state electron spin transitions that have coherence lifetimes often limited by spin flip-flop processes and spectral diffusion, even at very low temperatures. We investigate spin coherence in an optically excited state of an Er^{3+}: Y_{2}SiO_{5} crystal at temperatures from 1.6 to 3.5 K for a low 8.7 mT magnetic field compatible with superconducting resonators. Spin coherence and population lifetimes of up to 1.6 µs and 1.2 ms, respectively, are measured by optically detected spin echo experiments. Analysis of decoherence processes suggest that ms coherence can be reached at lower temperatures for the excited-state spins, whereas ground-state spin coherence would be limited to a few µs due to resonant interactions with other Er^{3+} spins in the lattice and greater instantaneous spectral diffusion from the radio-frequency control pulses. We propose a quantum transducer scheme with potential for close to unity efficiency that exploits the advantages offered by spin states of the optically excited electronic energy levels.