INORGANIC MATERIALS FOR ANOMALOUS-DISPERSION PHASE-MATCHED 2ND-HARMONIC GENERATION - RUBIDIUM TITANYL ARSENATE ISOMORPHS, RB[TI(1-2X)LN(X)NB(X)]OASO4

The defect chemistry and optical properties of Rb[Ti(1-2x)Ln(x)Nb(x)]OAsO4 are reported. The solid solubility of lanthanide ions in these materials decreases exponentially as the size of the lanthanide ion increases. The high-temperature chemistry is complex: Rb[Ti(1-2x)Ln(x)Nb(x)]OAsO4 is formed at low dopant concentrations and Rb-1-z square(z)[Ti(1-2x-z)Ln(x)Nb(x+z)]OAsO4 and additional phases are formed at higher concentrations. All the materials exhibit absorption spectra that are characteristic of the particular lanthanide ion in the structure. The charge transfer band is red-shifted 0-27 nm relative to RbTiOAsO4 (midpoint 331 nm). The magnitude of the shift depends on the method of sample preparation. Second-harmonic intensities measured at 532 nm decrease exponentially as the lanthanide ion concentration is increased.