Optical effects of defect diffusion in Bi4Ge3O12 and Bi12 GeO20 produced by ion implantation

Abstract

Planar optical waveguides have been formed in Bi₄Ge₃O₁₂ and Bi₁₂GeO₂₀ by helium-ion implantation at 77 and 300 K. Index profiles were determined at 488, 633 and 1150 nm. The two materials behave quite differently in terms of the relationships between index changes and the energy deposition from nuclear collisions and electronic excitation. Effects discussed include simple-damage production, radiation-enhanced diffusion of damage from the collision region and relaxation of the lattices into higher-index phases.