Effect of stress on the V-bands in potassium bromide at room temperature

Abstract

Abstract The V-bands which are present in KBr at room temperature do not show anisotropic absorption after exposure to plane polarized light, at room or liquid nitrogen temperature. The effects of stress on these bands have been investigated. No appreciable changes have been observed for applied stresses below the elastic limit. Beyond the elastic limit, a [001] uniaxial stress causing slip on the (101) planes gave the following results: (a) An increase in the absorption in the region of the V 2 -band, and a decrease in the absorption in the V 3 -band region. (b) For light incident along [100], absorption with the electric vector E parallel to [001] was larger than with E parallel to [010]. (c) For light incident along [010], the absorption was nearly isotropic. The effects (a), (b) and (c) were observed also in crystals which were plastically deformed prior to irradiation. The annealing of the V 2 and V 3 bands has been studied under stress, and with the stress relieved. It is suggested that the results can be explained by the interaction of anisotropic defects with the stress fields around dislocations.