Injected-charge-driven increase in electro-optic effect of KTN crystals

We report a significant increase in the electro-optic (EO) effect of KTaxNb1-xO3 (KTN) crystals that we achieved by injecting carriers into them. The dielectric constant of KTN was increased approximately twofold by carrier injection. The EO beam scanning performance was effectively improved by the increase in the EO effect resulting from the increased dielectric constant. The estimated densities of the trapped electrons were as small as 5.8 × 1020m-3. The very small quantity of injected electrons greatly affected the dielectric constant and EO effect of the KTN crystals.