Study of the Electro-Reflectance of KDP

抄録

The electro-reflectance spectra of KDP have been measured by applying an electric field along the z-axis in the photon energy region from 6 eV to 10.5 eV, from which the changes of the real part (Δε₁) and imaginary part (Δε₂) of the dielectric constant are deduced. The spectrum of Δε₂ shows an absorption band-like shape at about 8.3 eV, a little lower energy than the reflection summit, and is interpreted as the change of the absorption intensity relevant to the electron transfer from the oxygen ions of a PO₄ tetrahedron to the nearby hydrogen ions. The spectrum of Δε₁ shows a dispersion-like shape around the Δε₂ band, and the change in the region below 7 eV well corresponds to the spectrum of the electro-optic coefficient ρ₆₃, though discrepancy is found in the absolute values of Δε₁ between the one measured and the one estimated from the electro-optic effect.