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The focusing effect of graded index photonic crystals

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Original languageEnglish
Article number171108
JournalApplied Physics Letters
Issue number17
Publication statusPublished - 2008
Externally publishedYes
Publication typeA1 Journal article-refereed


We describe an approach to implement graded index (GRIN) structures using two-dimensional photonic crystals (PCs). The lattice spacing along the transverse direction to propagation is altered and we show, both theoretically and experimentally, that such a spatial perturbation is an effective way to obtain GRIN PC. The response of the structure to spatially wide incident beams is investigated and strong focusing behavior is observed. The large spot size conversion ratio can be attainable and is mainly limited by the finite size of the structure. The designed GRIN PC shows promise for use in optical systems that require compact and powerful focusing elements compared to the traditional bulky lenses.

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