Michael Goldman

Quantum Interference of Single Photons from Remote Nitrogen- Vacancy Centers in Diamond

We demonstrate quantum interference between indistinguishable photons emitted by two nitrogen-vacancy centers in distinct diamond samples separated by two meters. Macroscopic solid immersion lenses are used to enhance photon collection efficiency. Quantum interference is verified by measuring a value of the second-order cross-correlation function g((2))(0)=0.35±0.04<0.5. In addition, optical transition frequencies of two separated nitrogen-vacancy centers are tuned into resonance with each other by applying external electric fields. An extension of the present approach to generate entanglement of remote solid-state qubits is discussed.

Phonon-induced population dynamics and intersystem crossing in nitrogen-vacancy centers.

We report direct measurement of population dynamics in the excited state manifold of a nitrogen-vacancy (NV) center in diamond. We quantify the phonon-induced mixing rate and demonstrate that it can be completely suppressed at low temperatures. Further, we measure the intersystem crossing (ISC) rate for different excited states and develop a theoretical model that unifies the phonon-induced mixing and ISC mechanisms. We find that our model is in excellent agreement with experiment and that it can be used to predict unknown elements of the NV centers electronic structure. We discuss the models implications for enhancing the NV centers performance as a room-temperature sensor.

State-selective intersystem crossing in nitrogen-vacancy centers

Motivated by recent measurements of state-selective intersystem crossing (ISC) in the nitrogen-vacancy (NV) center in diamond (see companion PRL), a new microscopic model is developed of the key ISC mechanism. These nonradiative transitions between states of different spin multiplicity are pivotal in the optical initialization and readout of the NV centers electronic spin, which has created a diverse range of room-temperature applications in metrology and quantum information science.