Realization of .... in 1D slab waveguide.pdf (1.09 MB)
Download fileRealization of “trapped rainbow” in 1D slab waveguide with surface dispersion engineering
journal contribution
posted on 2016-09-12, 00:00 authored by Rui Yang, Wenkan Zhu, Jingjing LiWe present a design of a one dimensional dielectric waveguide
that can trap a broadband light pulse with different frequency component
stored at different positions, effectively forming a “trapped rainbow”
[Nature 450, 397 (2007)]. The spectrum of the rainbow covers the whole
visible range. To do this, we first show that the dispersion of a SiO2
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-H¨anchen 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.