Variable gradient refractive index engineering: design, growth and electro-deflective application of KTa1−xNbxO3

Abstract

Gradient refractive index (GRIN) optical materials have received substantial attention because of their applications in integrated imaging and fiber optics. The refractive index gradient of most GRIN materials cannot be adjusted after fabrication, which limits the widespread application of GRIN materials. A variable GRIN material is proposed which utilizes the controllable quadratic electro-optic coefficient distribution in single crystals of potassium tantalate niobate (KTa_1−xNb_xO₃). By using the phase diagram of KTa_1−xNb_xO₃, niobium composition gradient KTa_1−xNb_xO₃ single crystals were designed and successfully grown to achieve the gradient distribution of a quadratic electro-optic coefficient by controlling growth conditions. Based on this variable, GRIN KTa_1−xNb_xO₃, a novel high-speed electro-deflector, was produced.