85,690 research outputs found
Highly-tunable formation of nitrogen-vacancy centers via ion implantation
We demonstrate highly-tunable formation of nitrogen-vacancy (NV) centers
using 20 keV 15N+ ion implantation through arrays of high-resolution apertures
fabricated with electron beam lithography. By varying the aperture diameters
from 80 to 240 nm, as well as the average ion fluences from 5 x 10^10 to 2 x
10^11 ions/cm^2, we can control the number of ions per aperture. We analyze the
photoluminescence on multiple sites with different implantation parameters and
obtain ion-to-NV conversion yields of 6 to 7%, consistent across all ion
fluences. The implanted NV centers have spin dephasing times T2* ~ 3
microseconds, comparable to naturally occurring NV centers in high purity
diamond with natural abundance 13C. With this technique, we can
deterministically control the population distribution of NV centers in each
aperture, allowing for the study of single or coupled NV centers and their
integration into photonic structures.Comment: Related papers at http://pettagroup.princeton.ed
Creating diamond color centers for quantum optical applications
Nitrogen vacancy (NV) centers in diamond have distinct promise as solid-state
qubits. This is because of their large dipole moment, convenient level
structure and very long room-temperature coherence times. In general, a
combination of ion irradiation and subsequent annealing is used to create the
centers, however for the rigorous demands of quantum computing all processes
need to be optimized, and decoherence due to the residual damage caused by the
implantation process itself must be mitigated. To that end we have studied
photoluminescence (PL) from NV, NV and GR1 centers formed by ion
implantation of 2MeV He ions over a wide range of fluences. The sample was
annealed at C to minimize residual vacancy diffusion, allowing for
the concurrent analysis of PL from NV centers and irradiation induced vacancies
(GR1). We find non-monotic PL intensities with increasing ion fluence,
monotonic increasing PL in NV/NV and GR1/(NV + NV) ratios, and
increasing inhomogeneous broadening of the zero-phonon lines with increasing
ion fluence. All these results shed important light on the optimal formation
conditions for NV qubits. We apply our findings to an off-resonant photonic
quantum memory scheme using vibronic sidebands
NV-centers in Nanodiamonds: How good they are
This paper presents a method for determination of the size distribution for
diamond nanocrystals containing luminescent nitrogen-vacancy (NV) centers using
the luminescence intensity only. We also revise the basic photo physical
properties of NV centers and conclude that the luminescence quantum yield of
such centers is significantly smaller than the frequently stated 100\%. The
yield can be as low as 5\% for centers embedded in nanocrystals and depends on
their shape and the refractive index of the surrounding medium. The paper also
addresses the value of the absorption cross-section of NV centers
Local formation of nitrogen-vacancy centers in diamond by swift heavy ions
We exposed nitrogen-implanted diamonds to beams of swift uranium and gold
ions (~1 GeV) and find that these irradiations lead directly to the formation
of nitrogen vacancy (NV) centers, without thermal annealing. We compare the
photoluminescence intensities of swift heavy ion activated NV- centers to those
formed by irradiation with low-energy electrons and by thermal annealing. NV-
yields from irradiations with swift heavy ions are 0.1 of yields from low
energy electrons and 0.02 of yields from thermal annealing. We discuss possible
mechanisms of NV-center formation by swift heavy ions such as electronic
excitations and thermal spikes. While forming NV centers with low efficiency,
swift heavy ions enable the formation of three dimensional NV- assemblies over
relatively large distances of tens of micrometers. Further, our results show
that NV-center formation is a local probe of (partial) lattice damage
relaxation induced by electronic excitations from swift heavy ions in diamond.Comment: to be published in Journal of Applied Physic
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