Optical and electrical readout of diamond NV centers in dependence of the excitation wavelength

Abstract

Nitrogen-vacancy (NV) centers in diamond can be read out optically or electrically. To better understand the physics of their internal electronic transitions as well as ionization and recharging, we study the spin contrast observed in both readout methods as a function of the excitation wavelength for both single NV centers and ensembles. While the optical readout works best between 525 and 550 nm, the highest electrical spin contrast is achieved by resonantly exciting the NV0 zero-phonon line at 575 nm. Additional spectral features attributed to a further excited state of NV−, phonon sidebands and tunnel coupling to nitrogen donors are observed and discussed.