Single Molecule Magnetic Resonance Spectroscopy Under Ambient Conditions With Nitrogen-Vacancy Center In Diamond

The past half century has seen rapid emergence and advances of single-molecule techniques,which have deepened our understanding of the micro-world,and unprece-dentedly improved our ability to control the micro-systems.However,current single-molecule techniques,limited by working principles,can't achieve in situ and non-invasive detection,or are difficult to conduct stable and precise structure analysis.Mag-netic resonance(MR)is a non-invasive method,which could extract conformational and structural information from sample,and has been widely applied in physics,chemistry,material,biology and medicine.Conventional MR relies on signal accumulation from billions of molecules.Pushing the sensitivity to single molecule is one of the most im-portant subjects in MR research,while facing numerous challenges.Most recent results show that nitrogen-vacancy(NV)center in diamond could perform as a new-type sen-sor under ambient conditions and has the potential of detecting single molecules.In this thesis,we built up platform for optically detected magnetic resonance(ODMR),and developed new methods of quantum control over single NV center.Based on these techniques,we get the first magnetic spectrum from single protein.1.We built up a multi-band ODMR platform,and developed high-accuracy quan-tum control techniques over NV center.We demonstrated Rabi oscillation based on over 1000 Landau-Zenner tunnelings.This provides a method of controlling quantum coherence robust to noises from driving fields.We implemented dynamically corrected quantum logic gates with composite pulses.This provides a quantum control method robust to noises from spin bath.2.Based on the above techniques,we made N V center as a quantum interferometer.We use it to detect and polarize single dark spin in diamond,as a proof of principle for single molecule detection.Quantum logic cooling also demonstrates that the dark spin can be harnessed as qubit resources.Furthermore,under ambient conditions,we successfully detected an electron spin label outside of diamond about 10 nm away from NV center.This is the first magnetic resonance spectrum of single protein.We extracted information of molecule dynamics from spectral analysis.3.The signal from single molecule is normally very weak.Here we proposed to improve the detecting sensitivity with a more efficient method,based on combination of photo-ionizing process and single electron transistor.Firstly we used single electron transistor to observe photo-ionization and Stark effect of single rare-earth ion,and pro-posed a method of characterizing transistor at nano-scale.We discussed the prospect of high-efficiency and high-flux single-molecule study with this method.