Tune the “rainbow” trapped in a multilayered waveguide

National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University Nanjing 210093, China

^(a) rwpeng@nju.edu.cn
^(b) muwang@nju.edu.cn

Received: 14 June 2012
Accepted: 8 August 2012

Abstract

The “rainbow”, where the light waves with different frequencies separate spatially, is confined in a self-similar waveguide with a hollow core coated by a coaxial dielectric/liquid-crystal multilayer. Due to the intrinsic self-similar furcation of the system, multiple transmission bands emerge in the photonic band structure, a “rainbow” is trapped as cladding modes in the waveguide. Both photonic bands and transmission modes can be tuned by changing temperature, hence the “rainbow” changes the colors in the waveguide. This effect can be applied in designing temperature-dependent integrated photonic devices, such as tunable on-chip spectroscopy, on-chip color-sorters, and photon sorters for spectral imaging.