Boris Naydenov (Jörg Wrachtrup - group)
Controlled generation of diamond color centers
Nitrogen-Vacancy (NV) centers in diamond have been intensively studied by many research groups in the recent years since they are very good candidates for qubits for a solid state quantum computer at room temperature. Here we report some of our latest experiments on NV centers for their application in quantum information processing (QIP). For the first time we demonstrate the coupling of two electron spins belonging to two distant NV centers. This pair was created by high energy focused ion implantation of nitrogen in ultra pure diamond. Double electron-electron resonance measurements reveal a 9.8 (±0.1) nm distance between the NVs.
Using specially grown isotopically pure CVD diamond we show that the electron spin coherence time T2 can be increased up to 2 ms at ambient conditions. In this sample the concentrations of the main sources of decoherence, namely paramagnetic impurities and 13C nuclei, are reduced below 1013/cm2 and 0.3 % respectively. This result indicates that two NV centers separated by more than 50 nm can be coherently coupled.
We also report the production of color centers in diamond emitting at 470 nm (TR12 center) by implanting carbon ions. Moreover, second-order correlation function measurements reveal that single photon emitters can be created by adjusting the implanted dose. The fluorescence lifetime of these defects at low temperature was measured to be 3 ns, which makes them useful as single photon sources for QIP.
