Determination of the refractive indices of layers in a multilayer stack bya guided-wave technique

The m-lines technique is used to measure the refractive indices and thickne sses of layers embedded in a multilayer stack. The multilayer considered is deposited by ion plating. Its formula is silica-4H-L-4H-L-6H-air, where H and L denote Ta2O5 and SiO(2)lambda/4 layers, respectively, with lambda = 5 14.5 nm. Measurements indicate that the refractive index of Ta2O5 is 5 x 10 (-3) greater when the layer is close to air than when the layer is inside t he coating and that the Ta2O5 is slightly more birefringent. (C) 1999 Optic al Society of America.