Waveguides formed via direct deposition of reflective material on isolated surfaces of the waveguides rather than on every surface of the waveguides are described. It is contemplated that direct deposition facilitates deposition on isolated surfaces. Deposition only on isolated surfaces reduces costs and risks. Cost is reduced by reducing the amount of reflective material required. Risk of metal particles plugging the waveguide reduced both by the decrease in amount of reflective material used, and in the method of depositing it.