Enhancing one dimensional sensitivity with plasmonic coupling

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Issue Date
2014
Authors
O’Mullane, Samuel
Peterson, Brennan
Race, Joseph
Keller, Nick
Diebold, Alain C.
Publisher
Optics Express
Keywords
ellipsometry , polarimetry , plasmonics , scatterometry , unconverged rigorous coupled wave approximation (RCWA) , simulation
Abstract
In this paper, we propose a cross-grating structure to enhance the critical dimension sensitivity of one dimensional nanometer scale metal gratings. Making use of the interaction between slight changes in refractive index and localized plasmons, we demonstrate sub-angstrom scale sensitivity in this structure. Compared to unaltered infinite metal gratings and truncated finite gratings, this cross-grating structure shows robust spectra dependent mostly on the dimension of the smaller line width and pitch. While typical scatterometry simulations show angstrom resolution at best, this structure has demonstrated picometer resolution. Due to the wide range of acceptable specifications, we expect experimental confirmation of such structures to soon follow.
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