Realization of "Trapped Rainbow" in 1D slab waveguide with Surface Dispersion Engineering

Abstract

We present a design of a one dimensional dielectric waveguide that can trap a broad band light pulse with different frequency component stored at different positions, effectively forming a "trapped rainbow"[1]. The spectrum of the rainbow covers the whole visible range. To do this, we first show that the dispersion of a ${\text{SiO}}_2$ waveguide with a Si grating placed on top can be engineered by the design parameter of the grating. Specifically, guided modes with zero group velocity(frozen modes) can be realized. Negative Goos-Hänchen shift along the surface of the grating is responsible for such a dispersion control. The frequency of the frozen mode is tuned by changing the lateral feature parameters (period and duty cycle) of the grating. By tuning the grating feature point by point along the waveguide, a light pulse can be trapped with different frequency components frozen at different positions, so that a "rainbow" is formed. The device is expected to have extremely low ohmic loss because only dielectric materials are used. A planar geometry also promises much reduced fabrication difficulty.

References in corpus (5)

• Flat Dielectric Grating Reflectors with High Focusing Power
• Experimental verification of the "rainbow" trapping effect in plasmonic graded gratings
• Experimental observation of the trapped rainbow
• Control of dispersion in photonic crystal waveguides using group symmetry theory
• Evanescent Gain in "Trapped Rainbow" Negative Refractive Index Heterostructures

Cited by in corpus (2)

• Rainbow Trapping in a Chirped Three-Dimensional Photonic Crystal
• The Effect of Symmetry Breaking in Coupled Cavity Photonic Crystal Waveguide on Dispersion Characteristics