MICROANALYTICAL INVESTIGATIONS ON OPTICAL-PHASE GRATINGS IN K(TIO)PO4SINGLE-CRYSTALS

The Rb/K ion exchange in micro-structured K(TiO)PO4 single crystals in contact with Rb containing nitrate melts results in ion-exchanged zon es with enlarged refractive index which works as an optical phase grat ing. The knowledge of the diffusion behavior was the prerequisite for the generation of optimum refractive index profiles. Therefore, the lo cal Rb/K concentration of ion-exchanged single crystals was determined with an electron probe microanalyzer (EPMA). The observed degree of i on exchange and the calculated Rb/K counterdiffusion coefficients were used to estimate the optimum ion exchange conditions. The diffusion-g enerated optical phase gratings show very narrow and deep ion-exchange d zones. The ratio of the ion penetration depths results in an extreme diffusion anisotropy D-Rb/K(c):D-Rb/K(b) approximate to 500:1.