OPTICAL TRAP ACTIVATION IN A PHOTOREFRACTIVE POLYMER

Optical trap activation has been observed to increase the steady-state diffraction efficiency by a factor of 3 in a photorefractive (PR) pol ymer, yl-2,2-tetramethylene-5-nitrobenzimidazoline):C-60 (PMMA:DTNBI:C -60). The increased diffraction efficiency is accompanied by an increa se in the PR storage lifetime but also by an increase in the character istic grating growth time of the PR grating. The optical activation of the deep trapping sites is observed to be a sublinear function of the optical irradiation power. Both spatially uniform trap activation and spatial patterning of the photorefractive response of the material ar e demonstrated.