Some physical properties of single crystals of normal and deuterated rubidium dihydrogen arsenate II. Electro-optic and dielectric properties

The electro-optic and dielectric constants of single crystals of rubidium dihydrogen arsenate grown in H₂O, and of rubidium dideuterium arsenate grown in D₂O, have been measured. On deuteration the relative dielectric constant K₃₃ is increased from 28·5 to 42·5 and K₁₁ is increased from 54·5 to 71·5 at 25°C. The half-wave retardation voltage V_λ/2, measured at 500 nm is decreased from 3·8 kv to 3 kv and the electro-optic constant r₆₃ is increased from 16·7×10⁻¹⁰ cm v⁻¹ to 21·6×10⁻¹⁰ cm v⁻¹ on deuteration. The loss tangent tan δ₃₃, measured at 1 kHz and at 25°C, is about 2·6 for D-RbDA and 5·2 for RbDA. The specific resistivity ρ₃₃ for RbDA is 3·4×10⁶ Ω cm and that for D-RbDA is 3·6×10⁷ Ω cm, measured at 25°C. The input power requirement using these crystals in an electro-optic modulator is compared to that of KDP.