Optical tuning of dielectric properties of Ba0.6Sr0.4TiO3-La(Mg0.5Ti0.5)O3 ceramics in the terahertz range

The dielectric properties of 0.4Ba(0.6)Sr(0.4)TiO(3)-0.6La(Mg0.5Ti0.5)O-3 ceramics and their tunability under external optical fields are investigated at room temperature by means of terahertz time-domain spectroscopy. Application of the optical field leads to an appreciable tuning of the permittivity, which reaches up to 16%. Meanwhile, the dielectric loss changes about 21%. From the results, we find that the change of refractive index has a linear relationship on scale with the applied light power. These findings are attributed to the internal space charge field in the ceramic caused by the excited free carriers. (c) 2013 AIP Publishing LLC.