Characterization of optical and nonlinear properties of periodically-poled RbTiOAsO4 in the mid-infrared range via difference-frequency generation

Tunable mid-infrared coherent radiation (3.25-3.7 mu m) is generated by quasi-phase-matched difference frequency generation in a multi-grating periodically-poled RbTiOAsO4 crystal. The spontaneous polarization and coercive field of Aux-grown RbTiOAsO4 are determined by polarization switching measurements. The nonlinear interaction enables us to explore the optical and nonlinear properties of this material in the mid-infrared range, where data is scarce. The measurements are used to derive a mid-infrared corrected dispersion equation for n(z) in RbTiOAsO4. This equation is in excellent agreement with previously published measurements of nonlinear interactions in periodically-poled RbTiOAsO4. The measured wavelength and temperature bandwidths are approximate to 48 nm cm and approximate to 29 degrees C cm, respectively. A relatively high temperature tuning slope of the phase-matched idler wavelength, -1.27 nm/degrees C, is measured. This may be useful for realizing temperature-tuned nonlinear devices.