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Polarization conversion in conical diffraction by metallic and dielectric subwavelength gratings
Nicolas Passilly1, Kalle Ventola, Petri Karvinen
1Department of Physics and Mathematics, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland. passilly@joensuu.fi
Applied Optics
|June 21, 2007
Summary
Subwavelength gratings can rotate light polarization by 90 degrees. Dielectric gratings offer higher efficiency for this polarization conversion compared to metallic ones.
Area of Science:
- Optics and Photonics
- Nanotechnology
- Materials Science
Background:
- Subwavelength gratings are crucial optical components for manipulating light polarization.
- Achieving efficient polarization rotation, specifically 90-degree conversion, is a key challenge in optical device design.
Purpose of the Study:
- To investigate subwavelength metallic and dielectric diffraction gratings for 90-degree linear polarization rotation.
- To compare the performance and efficiency of metallic versus dielectric gratings for polarization conversion.
Main Methods:
- Utilizing rigorous diffraction theory within a total-internal-reflection configuration.
- Analyzing the performance of both metallic and dielectric grating designs.
Main Results:
- Demonstrated full conversion from incident transverse electric (TE) to transverse magnetic (TM) zero-order field is achievable with both grating types.
- Dielectric gratings exhibit higher efficiency for polarization conversion compared to metallic gratings.
- Detailed discussion of fabrication aspects, constraints, and broadband wavelength behavior.
Conclusions:
- Dielectric subwavelength gratings are preferable for 90-degree polarization rotation due to higher efficiency.
- The findings provide insights into the design and application of polarization-rotating gratings.
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