Imaging of THz waves in 2D photonic crystal structures embedded in a slab waveguide

We present space- and time-resolved simulations and measurements of single-cycle terahertz (THz) waves propagating through two-dimensional (2D) photonic crystal structures embedded in a slab waveguide. Specifically, we use a plane wave expansion technique to calculate the band structure and a time-d...

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Bibliographic Details
Main Authors: Peier, P., Merbold, H., Pahinin, V., Nelson, Keith Adam, Feurer, T.
Other Authors: Massachusetts Institute of Technology. Department of Chemistry
Format: Article
Language:en_US
Published: Institute of Physics Publishing 2012
Online Access:http://hdl.handle.net/1721.1/70844
https://orcid.org/0000-0001-7804-5418
Description
Summary:We present space- and time-resolved simulations and measurements of single-cycle terahertz (THz) waves propagating through two-dimensional (2D) photonic crystal structures embedded in a slab waveguide. Specifically, we use a plane wave expansion technique to calculate the band structure and a time-dependent finite-element method to simulate the temporal evolution of the THz waves. Experimentally, we measure the space–time evolution of the THz waves through a coherent time-resolved imaging method. Three different structures are laser machined in LiNbO3 crystal slabs and analyzing the transmitted as well as the reflected THz waveforms allows determination of the bandgaps. Comparing the results with the calculated band diagrams and the time-dependent simulations shows that the experiments are consistent with 3D simulations, which include the slab waveguide geometry, the birefringence of the material, and a careful analysis of the excited modes within the band diagrams.