On the electro‐optic properties of single crystals of sodium, potassium and rubidium acid phthalates

Abstract
The linear electro‐optic (Pockels) effect in a series of alkali metal acid phthalate crystals has been studied. Single electro‐optic coefficients r and r for sodium (NaAP), potassium (KAP) and rubidium (RbAP) acid phthalates have been measured by employing the modified Mach–Zehnder interferometric technique. The best electro‐optic crystal in this series is RbAP with r = 9.10 × 10−12 m V−1, r = 3.05 × 10−12 m V−1 and a sizable figure of merit for electro‐optic phase retardation, comparable with that of KDP. The dispersion properties of the electro‐optic coefficients for KAP are discussed in detail.