Albert Anthony Ballman

Linear and nonlinear optical properties of flux‐grown KTiOAsO4

Single crystals of KTiOAsO4, a material which is isostructural with the well‐known nonlinear optical material KTiOPO4 (KTP), were grown by a flux process and its optical and dielectric properties characterized. Compared to KTP, KTiOAsO4 has a higher figure of merit for second‐harmonic generation, larger electro‐optic coefficients, and lower ionic conductivity. As a result, KTiOAsO4 should become a viable alternative for KTP.

Properties of doped and undoped crystals of single domain KTiOAsO4

Large single crystals of KTiOAsO4 (KTA) measuring up to 35×31×58 mm3 (along abc) are grown from the pure potassium arsenate self-fluxes and from the tungstate flux using the seeded high-temperature solution growth technique. Small amounts of Fe2O3, Sc2O3, or In2O3 (∼0.2–0.4 wt %) are added to the melt to promote single-domain formation in the flux-grown crystals. We report here the linear optical and nonlinear optical properties of these crystals. We observed an unusually strong optical birefringence increase with Fe2O3 dopant concentration [δ(nz−nx)∼0.017/wt % Fe]. This increase leads to a blue shift in the second-harmonic generation cutoff wavelength of as much as 37 nm for a ∼0.47 wt % Fe-dopant level in KTA.

KTIOPXAS1-XO4 OPTICAL WAVEGUIDES GROWN BY LIQUID PHASE EPITAXY

We report on a new type of optical waveguide based on the nonlinear optical material KTiOPO4 (KTP). Thin films of KTiOPxAs1−xO4 (5–50 μm) were grown on KTP substrates by liquid phase epitaxy using a tungstate flux. Energy‐dispersive x‐ray spectrometry reveals an abrupt increase in the arsenic concentration in the film, suggesting an abrupt, step‐like refractive index profile in these guides. Optical waveguiding at 0.633 μm was demonstrated in a 20‐μm‐thick KTiOP0.76As0.24O4 film grown on a {011} KTP substrate. The refractive index difference between the film and the substrate (Δn) was measured to be ∼0.012, which compares favorably with the value estimated from bulk crystal measurements of the end members. Variations in the design of these waveguides and several potential applications are discussed.

Preparation of single-domain KTiOAsO4 crystals for device application

We report here the crystal growth and characterization of single domain KTiOAsO4 crystals suitable for devices application. The presence of inversion domains were established by various techniques including piezoelectric resonances and electrostatic toning. Techniques for removing these domains from as grown crystals were discussed.