Wide bandwidth directional beaming via waveguide ports in photonic crystals

Abstract

We numerically and experimentally demonstrated highly directional emission from photonic crystals (PCs). Our structures comprise branched waveguide channels with a periodic doubling scheme. An incident electromagnetic wave can be first split into multiple beams using PC waveguide structures. The beams were then emitted at the output waveguide ports of the PC with the same phase, which resulted in a highly directional radiation pattern. Our results demonstrate that the full width at half maximum of the emission beam is nearly inversely proportional to the number of output waveguide ports. Typically, for a PC with sixteen output ports, the half-power beam width measured 4.8• , which was in good agreement with the calculated value of 4.1• . In contrast to the traditional beaming structures, our design did not involve grating-like structures, which resulted in a wider operation bandwidth.

Highly Efficient Two-Channel Drop Filter of Single Photons with One Drop Waveguide

“…Optical drop filters are the essential elements in photonic integrated circuits and dense wavelength division multiplexing (WDM) communication systems, since they have been applied as multiplexers, selector, modulators, and so on. Over the past two decades, a variety of investigation on optical drop filtering has been carried out in various systems, including fiber Bragg gratings [1]- [6], photonic crystal structures [7]- [17], plasmonic systems [18] [19], and microresonators [20]- [25], etc. Especially, whispering-gallery mode (WGM) resonators as filter components have attracted much attention owing to their high quality factors and compact sizes [26].…”

Enhanced photocurrent efficiency of a carbon nanotube p–n junction electromagnetically coupled to a photonic structure

“…By artificially modifying the composition and periodic arrangement in a photonic structure, the flow of light can be guided onto extremely localized regions of space. Recognizing these possibilities, several groups have already characterized photonic structures which can focus electromagnetic waves and provide highly directional light beams [6][7][8][9][10][11][12][13][14]. There has also been recent work in modifying photonic surfaces to produce beams with high transmission efficiencies [8].…”