Some Physical Properties of Single Crystals of Normal and Deuterated Potassium Dihydrogen Arsenate. II. Electro-optic and Dielectric Properties

Abstract

The electro‐optic and dielectric constants of single crystals of potassium dihydrogen arsenate, grown in H₂O, and potassium dideuterium arsenate, grown in D₂O, have been measured. On deuteration, the relative dielectric constant K₃₃ is increased from 24 to 31 and K₁₁ is increased from 60 to 70, measured at 25°C. The half‐wave retardation voltage V_λ/2, measured at 500 nm is decreased from 5.9 to 3.3 kV, and the electro‐optic constant γ₆₃ in increased from 11.0×10⁻¹⁰ cm/V to 19.5 cm/V on deuteration. The loss tangent tanδ₃₃ measured at 1 kHz and at 25°C is about 0.30 for KDA and 0.18 for D‐KDA. The specific resistivity ρ₃₃ for KDA is 7.2×10⁸Ω·cm, and that for D‐KDA is 5.1×10⁸Ω·cm, measured at 25°C. The input power requirement using these crystals in an electro‐optic modulator is compared to that of KDP.