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

Abstract

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.

Permittivity changes induced by injected electrons and field-induced phase transition in KTa1−xNbxO3optical beam deflectors

“…In addition to the deflection, we found another peculiar phenomenon, namely there is a significant increase in the permittivity caused by the electron injection. 13) Thus the two important parameters for the deflector, the charge density and the permittivity, are related to each other. This nonlinear effect might be related to nonlinearity in the dielectric properties found in ferroelectric materials.…”

Temperature dependence of Kerr coefficient and quadratic polarized optical coefficient of a paraelectric Mn:Fe:KTN crystal

“…Recently, research interests have converged on potassium tantalate niobate (KTN) crystal. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] KTN crystal, a perovskite-type oxide material, well recognized for its excellent EO performance where the index modulation is proportional to the square of the electric field, can realize rapid response, strong control of the refractive index and much lower driving energy comparing to LiNbO 3 for the same change ∆n in the refractive index. For this reason, KTN-based single crystal has been considered as promising materials, and has then been substantially investigated and successfully exploited in such diverse areas as EO deflection, [6][7][8] EO scanner, 9 a fast varifocal lens [10][11][12][13] and so on.…”