ELECTRONIC-STRUCTURE OF THE N-V CENTER IN DIAMOND - EXPERIMENTS

Quantum-beat spectroscopy has been used to observe excited states of t he N-V center in diamond. For the 1.945-eV optical transition, direct evidence is presented for the existence of GHz-scale fine structure, t ogether with a much larger 46-cm(-1) level splitting in the E state. A n interference effect observed in transient four-wave-mixing response is explained with a polarization selection rule involving Zeeman coher ence among magnetic sublevels. Also, detailed dephasing measurements v ersus temperature and wavelength have identified the decay mechanisms operative among the various states. A comparison of these results with ab initio calculations of excited electronic structure and interactio ns based on several multielectron models supports the conclusion that the N-V center is a neutral, two-electron center governed by a strong Jahn-Teller effect and weak spin-spin interactions.