Hochauflösende Mikroskopie und Spektroskopie an einzelnen Fehlstellenzentren in Diamant

Abstract

This thesis deals with the application of single Nitrogen-vacancy centers to precise localization techniques in microscopy and magnetic sensing of single spins in liquids. It will give an introduction to imaging theory and recent methods of superresolution microscopy. After that, basic properties of the Nitrogen-vacancy center will be described, as well as its applications to measurements of magnetic fields and external spins outside the diamond. The experimental part of this work presents a description of the configurations of the setup for the performed experiments. This is followed by a detailed discussion about the measurements and the results. Chapter 4 will present superresolution measurements on NV centers by GSD microscopy. With this nonlinear imaging technique, a resolution below 20 nm in the plane perpendicular to the optical axis have been achieved. In fact, we were able to resolve a pair of two NV centers as close as 14 nm. The main work of this thesis consists of a second type of experiment. Fluorescence imaging with one-nanometer accuracy (FIONA) was applied and adapted, to determine the depth of implanted NV centers. We report an achieved accuracy of about 2.6 nm along the optical axis for shallow emitters. Additionally, it was shown that the shift of a focal point in a high refractive index material is dependent on its distance to the surface. For this issue a theoretical model was calculated that matches the behavior of our experimental results. The last type of performed experiments uses shallow implanted single NV centers to combine the determination of depth to their sensitivity of external spins. This was done by measuring the effect of single spins in liquids near the surface of the diamond on the coherence times of NV centers. Hence, we show the realization of a microfluidic chamber and prove a sensitivity of the NV centers to a small number (< 100) of external spins.