A proton-implanted planar waveguide fabricated in terbium gallium garnet crystal

Abstract

The investigation on the terbium gallium garnet (TGG) crystal waveguides in the visible and near-infrared bands is significant for potential applications in science and technology. In this work, we report on a TGG planar waveguide based on the proton irradiation with an energy of 400 keV and a dose of [Formula: see text] ions/cm2. The annealing treatments are adopted to improve optical performances of the waveguide on the conditions of 260[Formula: see text]C and 410[Formula: see text]C severally for 1 h. The dark-mode spectra and the refractive index distributions of the TGG waveguide are obtained before and after the thermal treatments. There is a strange phenomenon that nine modes are observed on the m-line curve after the annealing treatment at 410[Formula: see text]C. The theoretical and experimental results demonstrate that the fabricated waveguide annealed at the temperature of 410[Formula: see text]C can propagate more guided modes and have better capacity to confine light.