To describe experiments on fluorescence excitation of single N-V defect centers in diamond we have used the double well potential (DWP) model which incorporates the possibility of tunneling the nitrogen atom into the vacancy both in ground and excited electronic states of the center. Fluorescence and linear absorption spectra are calculated, DWP's parameter values for N-V centers are determined and manifestations of their variations due to local diamond lattice distortions in fluorescence spectra of various single N-V centers are studied.
Summary form only given. Fluorescence excitation method of single molecule spectroscopy has been applied recently to study individual nitrogen-vacancy (N-V) defect centers in diamond. These objects are of great interest owing to the proposal to build quantum computer at /sup 13/C nuclear spins neighboring the N-V center. Based on new spectroscopic information we have developed simple models of the N-V center and used them to describe a wide range of experiments dealing both with single centers and with their ensembles. The first model emphasizes possible tunneling of N atom into vacancy and describes that in terms of double well potentials. The second model takes into account the spin-triplet character of the ground electronic state of the center and allows to describe a variety of fluorescence detected magnetic resonance phenomena.
We report a magnetic field dependence of fluorescence of diamond single crystals containing NV
− centers. In such spectra, numerous sharp lines are found, which correspond to Level Anti-Crossings (LACs) in coupled spins systems comprising an NV
− center. Theoretical modeling of such "LAC-spectra" enables characterization of paramagnetic defect centers and determination of their magnetic resonance parameters, such as zero-field splitting and hyperfine coupling constants. The outlined method thus enables sensitive detection of paramagnetic impurities in diamond crystals.