Optical and Spin Properties of NV Center Ensembles in Diamond Nano Pillars

Nitrogen vacancy NV color centers in diamond are excellent quantum sensors possessing high sensitivity and nano scale spatial resolution. Their integration in photonic structures is often desired, since it leads to an increased photon emission and also allows the realization of solid state quantum technology architectures. Here, we report the fabrication of diamond nano pillars with diameters up to 1000 nm by electron beam lithography and inductively coupled plasma reactive ion etching in nitrogen rich diamonds type Ib with [100] and [111] crystal orientations. The NV centers were created by keV He ion bombardment and subsequent annealing, and we estimate an average number of NVs per pillar to be 4300 300 and 520 120 for the [100] and [111] samples, respectively. Lifetime measurements of the NVs excited state showed two time constants with average values of amp; 964;1 amp; 8776; 2 ns and amp; 964;2 amp; 8776; 8 ns, which are shorter as compared to a single color center in a bulk crystal amp; 964; amp; 8776; 10 ns . This is probably due to a coupling between the NVs as well as due to interaction with bombardment induced defects and substitutional nitrogen P1 centers . Optically detected magnetic resonance measurements revealed a contrast of about 5 and average coherence and relaxation times of T2 [100] 420 40 ns, T2 [111] 560 50 ns, and T1 [100] 162 11 amp; 956;s, T1 [111] 174 24 amp; 956;s. These pillars could find an application for scanning probe magnetic field imagin