Abstract
Strong emission in the near infra-red has been observed in infra-red cathodoluminescence topographs of synthetic diamonds and is attributed to the 1.40 eV vibronic system reported by Dean (1965). In a large synthetic diamond the emission is confined to the ‘111’ growth sectors, being undetectable in sectors of the other major growth form ‘100’ and in sectors of the minor forms ‘110’ and ‘113’. The infra-red emission is partially polarized: in each octahedral growth sector the E vector is predominantly parallel to the local growth facet.