Transient phase gratings in ZnO induced by two-photon absorption

Abstract

The light diffracted from transient holographic phase gratings has been used to investigate free-carrier and thermal effects in ZnO. The gratings were optically induced by two-photon absorption of two interfering optical beams. A sequential appearance of two gratings was observed: one from free carriers and the other from lattice heating. Diffraction efficiencies varied with the fourth power of the intensity of the interfering beams and reached ≈ 10% at the highest intensities.