Quasinondestructive readout in a photorefractive polymer

An important physical phenomenon, quasinondestructive reading, has been observed for the first time in a photorefractive polymeric material, PMMA (poly-methylmethacrylate) (1,3-dimethyl-2,2-tetramethylene-5- nitrobenzimidazoline). In addition, a maximum steady-state diffraction efficiency of 7% (125 μm sample thickness) and a net two-beam coupling gain of 16 cm-1 are observed in this polymer. A two-trap-level model, in which the levels are populated sequentially, qualitatively mimics the intensity-dependent decay rate and the transition to quasinondestructive reading. © 1994 The American Physical Society.