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arXiv · 0809.5242

Large bandwidth, highly efficient optical gratings through high index materials

Helmut Rathgen·H. L. Offerhaus
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Abstract

We analyze the diffraction characteristics of dielectric gratings that feature a high index grating layer, and devise, through rigorous numerical calculations, large bandwidth, highly efficient, high dispersion dielectric gratings in reflection, transmission, and immersed transmission geometry. A dielectric TIR grating is suggested, whose -1dB spectral bandwidth is doubled as compared to its all-glass equivalent. The short wavelength diffraction efficiency is additionally improved by allowing for slanted lamella. The grating surpasses a blazed gold grating over the full octave. An immersed transmission grating is devised, whose -1dB bandwidth is tripled as compared to its all-glass equivalent, and that surpasses an equivalent classical transmission grating over nearly the full octave. A transmission grating in the classical scattering geometry is suggested, that features a buried high index layer. This grating provides effectively 100% diffraction efficiency at its design wavelegth, and surpasses an equivalent fused silica grating over the full octave.

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Helmut Rathgen, H. L. Offerhaus. 2008-09-30. Large bandwidth, highly efficient optical gratings through high index materials. https://doi.org/10.1364/oe.17.004268

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