Quantum metrology, atomic sensing and novel imaging

Single spin magnetometry

Different roads have been taken towards single spin detection. Most prominent are atomic force microscopy and scanning tunneling microscopy that were able to achieve single electron spin detection over past decade, however conditions were limited to cryogenic temperatures. Our institute in close cooperation with several world leading groups in biology, physics and material science develop the novel approach to image single electron and nuclear spins under ambient conditions. The probe system is an ultrasensitive atomic magnetometer based on single electron spins associated Nitrogen-Vacancy (NV) color centers in diamond. It was shown that single NV centers can be individually created (1-3), optically polarized and detected, and exhibit excellent coherence properties even at room temperature. Recently, coherent control of NV electronic spin qubits has been used to sense and manipulate nearby individual electronic and nuclear spins in a diamond lattice. It was also demonstrated that fluorescing diamond nanocrystals containing NV defects can be used as markers for bioimaging applications. Such markers have attracted wide interest because of unprecedented photostability and non-toxicity. The main idea behind our research goal is the use excellent spin properties of NV defects for the precision sensing and imaging of external magnetic fields with sensitivity that is high enough to detect single electron and nuclear spins under ambient conditions. The impact of the project is far reaching. When successful, it will allow for imaging biologically relevant spins in living cells and resolving structure of single proteins.

_{Related publications}

_{Fedder H, Dolde F, Doherty MW, et al.: Electric-field sensing using single diamond spins. Nature Physics. 2011, 7:459-463.}

_{Balasubramanian G, Neumann P, Twitchen D, et al.: Ultralong spin coherence time in isotopically engineered diamond. Nature Materials. 2009, 8:383-387.}

_{Jelezko F, Balasubramanian G, Chan IY, et al.: Nanoscale imaging magnetometry with diamond spins under ambient conditions. Nature. 2008, 455:648-U646}