19 research outputs found
Germanium Vacancy in Diamond Quantum Memory Exceeding 20 ms
Negatively charged group-IV defects in diamond show great potential as
quantum network nodes due to their efficient spin-photon interface. However,
reaching sufficiently long coherence times remains a challenge. In this work,
we demonstrate coherent control of germanium vacancy center (GeV) at
millikelvin temperatures and extend its coherence time by several orders of
magnitude to more than 20 ms. We model the magnetic and amplitude noise as an
Ornstein-Uhlenbeck process, reproducing the experimental results well. The
utilized method paves the way to optimized coherence times of group-IV defects
in various experimental conditions and their successful applications in quantum
technologie
Transform-Limited Photon Emission From a Lead-Vacancy Center in Diamond Above 10 K
Transform-limited photon emission from quantum emitters is essential for
high-fidelity entanglement generation. In this study, we report the coherent
optical property of a single negatively-charged lead-vacancy (PbV) center in
diamond. Photoluminescence excitation measurements reveal stable fluorescence
with a linewidth of 39 MHz at 6 K, close to the transform-limit estimated from
the lifetime measurement. We observe four orders of magnitude different
linewidths of the two zero-phonon-lines, and find that that the phonon-induced
relaxation in the ground state contributes to this huge difference in the
linewidth. Due to the suppressed phonon absorption in the PbV center, we
observe nearly transform-limited photon emission up to 16 K, demonstrating its
high temperature robustness compared to other color centers in diamond.Comment: 13 pages,4 figure
Readout and Control of a Single Nuclear Spin with a Metastable Electron Spin Ancilla
Electron and nuclear spins associated with point defects in insulators are promising systems for solid-state quantum technology1, 2, 3. The electron spin is usually used for readout and addressing, and nuclear spins are used as exquisite quantum bits4, 5 and memory systems3, 6. With these systems, single-shot readout of single nuclear spins5, 7 as well as entanglement4, 8, 9, aided by the electron spin, have been shown. Although the electron spin in this example is essential for readout, it usually limits the nuclear spin coherence10, leading to a quest for defects with spin-free ground states9, 11. Here, we isolate a hitherto unidentified defect in diamond and use it at room temperature to demonstrate optical spin polarization and readout with exceptionally high contrast (up to 45%), coherent manipulation of an individual excited triplet state spin, and coherent nuclear spin manipulation using the triplet electron spin as a metastable ancilla. We demonstrate nuclear magnetic resonance and Rabi oscillations of the uncoupled nuclear spin in the spin-free electronic ground state. Our study demonstrates that nuclei coupled to single metastable electron spins are useful quantum systems with long memory times, in spite of electronic relaxation processes.Engineering and Applied Science
Pulsed Photoelectric Coherent Manipulation and Detection of N − V Center Spins in Diamond
Hybrid photoelectric detection of NV magnetic resonances (PDMR) is
anticipated to lead to scalable quantum chip technology. To achieve this goal,
it is crucial to prove that PDMR readout is compatible with the coherent spin
control. Here we present PDMR MW pulse protocols that filter background
currents related to ionization of NS0 defects and achieve a high contrast and
S/N ratio. We demonstrate Rabi and Ramsey protocols on shallow
nitrogen-implanted electronic grade diamond and the coherent readout of ~ 5 NV
spins, as a first step towards the fabrication of scalable photoelectric
quantum devices
Electrical-Readout Microwave-Free Sensing with Diamond
While nitrogen-vacancy (NV-) centers have been extensively investigated in
the context of spin-based quantum technologies, the spin-state readout is
conventionally performed optically, which may limit miniaturization and
scalability. Here, we report photoelectric readout of ground-state
cross-relaxation features, which serves as a method for measuring electron spin
resonance spectra of nanoscale electronic environments and also for
microwave-free sensing. As a proof of concept, by systematically tuning NV
centers into resonance with the target electronic system, we extracted the
spectra for the P1 electronic spin bath in diamond. Such detection may enable
probing optically inactive defects and the dynamics of local spin environment.
We also demonstrate a magnetometer based on photoelectric detection of the
ground-state level anticrossings (GSLAC), which exhibits a favorable detection
efficiency as well as magnetic sensitivity. This approach may offer potential
solutions for determining spin densities and characterizing local environment