Spin dynamics in the optical cycle of single nitrogen-vacancy centres in diamond

Abstract

We investigate spin-dependent decay and intersystem crossing (ISC)
in the optical cycle of single negatively charged nitrogen-vacancy (NV) centres
in diamond. We use spin control and pulsed optical excitation to extract both
the spin-resolved lifetimes of the excited states and the degree of optically
induced spin polarization. By optically exciting the centre with a series of
picosecond pulses, we determine the spin-flip probabilities per optical cycle,
as well as the spin-dependent probability for ISC. This information, together
with the independently measured decay rate of singlet population, provides a full
description of spin dynamics in the optical cycle of NV centres. The temperature
dependence of the singlet population decay rate provides information about the
number of singlet states involved in the optical cycle.