Linear and nonlinear optical properties of erbium-implanted coherent arrayof submicron silica spheres

A coherent array of silica spheres, which was implanted with erbium ions, s howed nonlinear behavior at lambda=0.532 mu m. This was attributed to a lar ge nonlinear refraction effect, which was enhanced by the structure of the opaline matrix. In addition, near infrared photoluminescence measurements s howed an overall enhancement as a function of the sphere's size. A large ph otoluminescence peak was found around lambda=900 nm and attributed to the l ensing effect of the opaline matrix. (C) 2000 American Institute of Physics . [S0003-6951(00)00926-8].