New method enables superior light confinement in low-refraction-index microcavity
The trapping of photons in low-refraction-index materials is thought to be difficult in conventional photonic structures that employ total internal reflection. Specifically, the whispering gallery mode (WGM) microcavity, which is an important optical component, has to rely on a refraction index with high contrast to the surrounding environment to manifest excellent light confinement. A team led by Professor Yun-Feng Xiao at Peking University collaborated with researchers from the Harbin Institute of Technology, and demonstrated that an optical microcavity structure consisting of a low-refraction-index silica microtoroid that was directly bonded on a high-refraction-index silicon substrate supports high-Q fundamental WGMs. This work has been published in a recent issue of Optica.