Spatial separation of spectrum inside the tapered metamaterial optical waveguide

In this work, the optical metamaterials based on silver dendritic cells are prepared by electrochemical deposition, and its transmission and focusing behaviors are investigated. The experimental results show that the optical metamaterials reveal a multiple pass-band transmission spectrum and a prominent focusing effect at the wavelength corresponding to the maximum transmission coefficient. Two optical metamaterial samples are combined into a tapered optical waveguide, and the spectra of transmitted light at the surface of the tapered optical waveguide is measured by using the fiber spectrometer along the light propagation direction. The results demonstrate that each frequency component of the wave packet is stopped at a different waveguide thickness, leading to the spatial separation of its spectrum. The spatial separation of spectrum can be effectively tuned by adjusting the inclination of the tapered optical waveguide, which can be used for storing photons and slow-light research.