NaBa12(BO3)7F4 (NBBF) dichroic crystals: optical properties and dielectric permittivity

Abstract

Three NaBa₁₂(BO₃)₇F₄ crystals were grown in the BaO–BaF₂–B₂O₃–Na₂O system from three different compositions of high-temperature solution. With the use of optical spectroscopy, energy-dispersive X-ray spectroscopy, and the Schering bridge method it was found that the crystals revealed sharp differences in their optical and dielectric properties. The relative permittivity of the crystals in direction perpendicular to the optical axis reached 319(5). The minimum deviation technique was used for refractive index measurements.