Electrodynamic properties of single-crystal and thin-film strontium titanate

We present a comparative study of broadband electrodynamic properties of co planar waveguidcs made from nonlinear dielectric single-crystal and thin-hi m SrTiO3 (STO) with high-temperature superconducting thin-film YBa2Cu3O7-de lta electrodes. The waveguides that use single-crystal STO exhibit a monoto nic increase in refractive index, dielectric nonlinearity, and dissipation with decreasing temperature (from 80 K to 20 K), whereas those based on thi n-film STO show similar but weaker effects with increasing temperature. Und er de bias, both types of waveguides show reduced refractive index, but dis sipation increases in the case of single-crystal STO, while it decreases in the case of STO thin-films.