Optical detection of magnetic resonance in the photoexcited triplet state of a deep center in diamond

Abstract

From an optically detected magnetic resonance study of the 2.818-eV zero-phonon emission in brown diamond, direct evidence for the existence of a photoexcited phosphorescent triplet state in diamond has been obtained. The emission is attributed to a deep-center triplet state with spin-Hamiltonian parameters \ensuremath{\Vert}D\ensuremath{\Vert}=924\ifmmode\pm\else\textpm\fi{}2 MHz, \ensuremath{\Vert}E\ensuremath{\Vert}=198\ifmmode\pm\else\textpm\fi{}2 MHz, and g=2.00. The magnetic main axes are along [100], [011], and [011\ifmmode\bar\else\textasciimacron\fi{}]. Time-resolved microwave recovery and microwave-induced delayed phosphorescence experiments at 1.4 K yield lifetimes of the radiative sublevels of 0.5 and 1.8 ms, whereas the nonradiative sublevel has a lifetime of 23 ms.