14 research outputs found
Stark Tuning and Electrical Charge State Control of Single Divacancies in Silicon Carbide
Neutrally charged divacancies in silicon carbide (SiC) are paramagnetic color
centers whose long coherence times and near-telecom operating wavelengths make
them promising for scalable quantum communication technologies compatible with
existing fiber optic networks. However, local strain inhomogeneity can randomly
perturb their optical transition frequencies, which degrades the
indistinguishability of photons emitted from separate defects, and hinders
their coupling to optical cavities. Here we show that electric fields can be
used to tune the optical transition frequencies of single neutral divacancy
defects in 4H-SiC over a range of several GHz via the DC Stark effect. The same
technique can also control the charge state of the defect on microsecond
timescales, which we use to stabilize unstable or non-neutral divacancies into
their neutral charge state. Using fluorescence-based charge state detection, we
show both 975 nm and 1130 nm excitation can prepare its neutral charge state
with near unity efficiency.Comment: 12 pages, 4 figure
Engineered Micro- and Nanoscale Diamonds as Mobile Probes for High-Resolution Sensing in Fluid
The nitrogen-vacancy (NV) center
in diamond is an attractive platform
for quantum information and sensing applications because of its room
temperature operation and optical addressability. A major research
effort focuses on improving the quantum coherence of this defect in
engineered micro- and nanoscale diamond particles (DPs), which could
prove useful for high-resolution sensing in fluidic environments.
In this work we fabricate cylindrical diamonds particles with finely
tuned and highly reproducible sizes (diameter and height ranging from
100 to 700 and 500 nm to 2 μm, respectively) using high-purity,
single-crystal diamond membranes with shallow-doped NV centers. We
show that the spin coherence time of the NV centers in these particles
exceeds 700 μs, opening the possibility for the creation of
ultrahigh sensitivity micro- and nanoscale sensors. Moreover, these
particles can be efficiently transferred into a water suspension and
delivered to the region to probe. In particular, we introduce a DP
suspension inside a microfluidic circuit and control position and
orientation of the particles using an optical trapping apparatus.
We demonstrate a DC magnetic sensitivity of 9 μT/√Hz
in fluid as well as long-term trapping stability (>30 h), which
paves
the way toward the use of high-sensitivity pulse techniques on contactless
probes manipulated within biological settings