The researchers placed a silicon nitride waveguide on a transparent nanoporous silicon oxide substrate that they specially developed to have a much lower refractive index than that of the waveguide.
其做法是在纳米级氧化硅透明衬底上生长氮化硅波导，衬底的折射率远小于波导。
2
They wanted to build a waveguide, a structure designed to send light in a particular direction, by drilling carefully spaced holes in a gallium arsenide crystal.