116 research outputs found
Electron spin phase relaxation of phosphorus donors in nuclear spin enriched silicon
We report a pulsed EPR study of the phase relaxation of electron spins bound
to phosphorus donors in isotopically purified 29^Si and natural abundance Si
single crystals measured at 8 K.Comment: 5 pages, 3 figure
Perfect alignment and preferential orientation of nitrogen-vacancy centers during CVD growth of diamond on (111) surfaces
Synthetic diamond production is key to the development of quantum metrology
and quantum information applications of diamond. The major quantum sensor and
qubit candidate in diamond is the nitrogen-vacancy (NV) color center. This
lattice defect comes in four different crystallographic orientations leading to
an intrinsic inhomogeneity among NV centers that is undesirable in some
applications. Here, we report a microwave plasma-assisted chemical vapor
decomposition (MPCVD) diamond growth technique on (111)-oriented substrates
that yields perfect alignment () of as-grown NV centers along a single
crystallographic direction. In addition, clear evidence is found that the
majority () of the aligned NV centers were formed by the nitrogen
being first included in the (111) growth surface and then followed by the
formation of a neighboring vacancy on top. The achieved homogeneity of the
grown NV centers will tremendously benefit quantum information and metrology
applications.Comment: 6 pages, 4 figures, changes to previous version: added
acknowledgemen
Enhancing fluorescence excitation and collection from the nitrogen-vacancy center in diamond through a micro-concave mirror
We experimentally demonstrate a simple and robust optical fibers based method
to achieve simultaneously efficient excitation and fluorescence collection from
Nitrogen-Vacancy (NV) defects containing micro-crystalline diamond. We
fabricate a suitable micro-concave (MC) mirror that focuses scattered
excitation laser light into the diamond located at the focal point of the
mirror. At the same instance, the mirror also couples the fluorescence light
exiting out of the diamond crystal in the opposite direction of the optical
fiber back into the optical fiber within its light acceptance cone. This part
of fluorescence would have been otherwise lost from reaching the detector. Our
proof-of-principle demonstration achieves a 25 times improvement in
fluorescence collection compared to the case of not using any mirrors. The
increase in light collection favors getting high signal-to-noise ratio (SNR)
optically detected magnetic resonance (ODMR) signals hence offers a practical
advantage in fiber-based NV quantum sensors. Additionally, we compacted the NV
sensor system by replacing some bulky optical elements in the optical path with
a 1x2 fiber optical coupler in our optical system. This reduces the complexity
of the system and provides portability and robustness needed for applications
like magnetic endoscopy and remote-magnetic sensing.Comment: 6 pages, 8 figure
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