In-plane anisotropy of nano-particle-doped glasses fabricated by multi-source simultaneous oblique-deposition

Nano-particle-doped glass thin films which have quite unique anisotropies in microscopic structures and in optical properties in the thin film planes were fabricated. SiO2 and three kinds of dopant materials, ZnTe, Au, or both ZnTe and Au, were deposited from two opposing oblique directions and then the samples were annealed. In the as-deposited samples the dopant materials formed nano-particles of metastable states surrounded by amorphous SiO2 and elongated to the direction normal to the two deposition directions. By post annealing, the dopant materials showed various changes of structural or chemical states: crystallization or solid state reactions, in individual nano-spaces surrounded by amorphous SiO2. In-plane anisotropies (polarization dependence) in the absorption coefficients and the absolute values of the third-order nonlinear optical susceptibilities were evaluated. One of the main origins of the anisotropies in the optical properties were revealed to be the polarization dependence of the distributions of the electric field of the incident light in the composite samples owing to the structural anisotropies. It was suggested that the local intensities of the electric field at the nano-particles were remarkably modified when both ZnTe and Au nano-particles were embedded in contact with each other. (C) 1997 Elsevier Science S.A.