Linearly polarized luminescence from linear defects in natural and synthetic diamond

Photomicrographic studies of luminescence from cut and polished surfaces of natural and synthetic diamonds stimulated by electron bombardment (cathodo- luminescence) reveal sharply defined blue-emitting lines which, it is believed, correspond to dislocations. The blue emission is linearly polarized with electric vector always parallel to the line. The degree of polarization is greatest (90% or more) when the lines are straight and oriented in 〈110〉 directions and this orientation is frequently observed.