Speaker
Description
Colour centers in diamond are in the focus of interest as single
photon emitters for quantum (Q) technologies. Q metrology has
already been demonstrated using the nitrogen-vacancy NV− center,
which has the crystal symmetry C3. However, defects with
D3d mirror symmetry, such as the group IV centers [1] SiV,
GeV, SnV and PbV, but also MgV, show optical properties superior
to NV, and are envisaged for single photon Q communication.
The D3d symmetry is the result of the impurity occupying
a lattice site in the center of two vacancies, the so-called
split-vacancy configuration as shown in Fig. 1 (bottom).
The most widely used method to create the colour centers is ion
implantation. Here one is faced with the challenge to maximize
the fraction of implanted impurities in the split-vacancy configuration
and to minimize structural damage resulting from ion
implantation in order to achieve a narrow spread of optical
properties of the centers.
We present results on the lattice location and confocal PL
measurements of radioactive 121Sn in diamond [2], where we
could unambiguously show that, following annealing at 920°C,
»30% of implanted Sn is found in the split-vacancy configuration.
Confocal photoluminescence (PL) revealed the characteristic
SnV− line at 621 nm, with an extraordinarily narrow ensemble
linewidth (2.3 nm) of near-perfect Lorentzian shape.
We are currently addressing colour center creation within a collaboration that includes KU Leuven Quantum Solid-State Physics (Belgium), University of Torino (Italy), and Universidade de Aveiro. Emission channeling (EC) lattice location experiments using the radioactive isotopes 121Sn, 209Pb, 27Mg, 45Ca and 89Sr are performed at the CERN-ISOLDE facility, while PL characterization of diamond samples implanted with stable isotopes (at KU Leuven or ISOLDE) takes place at the Universities of Torino and Aveiro.
References
[1] C. Bradac, W. Gao, J. Forneris, M.E. Trusheim, I. Aharonovich: “Quantum nanophotonics with group IV
defects in diamond”, Nature Communications 10, 5625 (2019).
[2] U. Wahl, et al: “Direct structural identification and quantification of the split-vacancy configuration for implanted
Sn in diamond”, Physical Review Letters 125, 045301 (2020).
