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Proceedings Paper

Highly efficient diffraction gratings and resonant plasma layers at IR wavelengths
Author(s): Johan H. Stiens; Galina A. Nemova; Peter F. Muys; Roger A. Vounckx
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Paper Abstract

In this work we investigate the interaction between rectangular-grooved transmission gratings and a resonant plasma layer at IR wavelengths. The gratings are designed to convert quasi-vertically incident light into quasi- horizontally propagating light in a high refractive index GaAs substrate with efficiencies of almost 90 percent in the first diffraction order. This can only be achieved by etching highly asymmetric '(lambda) /4' or '(lambda) ' gratings in a high refractive index material evaporated on the GaAs substrate. The resonant plasma layer (RPL) consists of a very thin highly doped n-GaAs layer whose plasma frequency is almost equal to the frequency of the incident light. Under these conditions Drude's formula shows that the refractive index almost vanishes due to plasma oscillations. The interaction between the diffraction modes and the RPL are investigated and optimized on the base of a rigorous coupled-wave analysis. This analysis reveals to which extent the RPL can influence the distribution of light between the zero and first diffraction orders. In the optimum position of the RPL, the first order diffraction efficiency changes from 90 percent down to 25 percent for a RPL thickness change of 40nm.

Paper Details

Date Published: 11 November 1999
PDF: 10 pages
Proc. SPIE 3897, Advanced Photonic Sensors and Applications, (11 November 1999); doi: 10.1117/12.369363
Show Author Affiliations
Johan H. Stiens, Vrije Univ. Brussel (Belgium)
Galina A. Nemova, Institute of Radio Engineering and Electronics (Russia)
Peter F. Muys, Laser Power Europe NV (Belgium)
Roger A. Vounckx, Vrije Univ. Brussel (Belgium)

Published in SPIE Proceedings Vol. 3897:
Advanced Photonic Sensors and Applications
Robert A. Lieberman; Anand Krishna Asundi; Hiroshi Asanuma, Editor(s)

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