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arXiv · 1108.3062

Observation of sub-Bragg diffraction of waves in crystals

Simon R. Huisman·Rajesh V. Nair·Alex Hartsuiker·Léon A. Woldering·Allard P. Mosk·Willem L. Vos
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Abstract

We investigate the diffraction conditions and associated formation of stopgaps for waves in crystals with different Bravais lattices. We identify a prominent stopgap in high-symmetry directions that occurs at a frequency below the ubiquitous first-order Bragg condition. This sub-Bragg diffraction condition is demonstrated by reflectance spectroscopy on two-dimensional photonic crystals with a centred rectangular lattice, revealing prominent diffraction peaks for both the sub-Bragg and first-order Bragg condition. These results have implications for wave propagation in 2 of the 5 two-dimensional Bravais lattices and 7 out of 14 three-dimensional Bravais lattices, such as centred rectangular, triangular, hexagonal and body-centred cubic.

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Simon R. Huisman, Rajesh V. Nair, Alex Hartsuiker, Léon A. Woldering, Allard P. Mosk, Willem L. Vos. 2011-12-15. Observation of sub-Bragg diffraction of waves in crystals. https://doi.org/10.1103/physrevlett.108.083901

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