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Emissivity measurements of 3D photonic crystals at high temperatures

Photonics and Nanostructures - Fundamentals and Applications

Luk, T.S.; Mclellan, T.; Subramania, G.; Verley, Jason C.; El-Kady, Ihab F.

An accurate methodology is presented to measure photonic crystal emissivity using a direct method. This method addresses the issue of how to separate the emissions from the photonic crystal and the substrate. The method requires measuring two quantities: the total emissivity of the photonic crystal-substrate system, and the emissivity of the substrate alone. Our measurements have an uncertainty of 4% and represent the most accurate measure of a photonic crystal's emissivity. The measured results are compared to, and agree very well with, the independent emitter model. © 2007 Elsevier B.V. All rights reserved.

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TYPE Conference YEAR 2008
ScopusOSTI

Molded transparent photopolymers and phase shift optics for fabricating three dimensional nanostructures

Optics Express

El-Kady, Ihab F.; Bogart, Gregory R.

This paper introduces approaches that combine micro/nanomolding, or nanoimprinting, techniques with proximity optical phase mask lithographic methods to form three dimensional (3D) nanostructures in thick, transparent layers of photopolymers. The results demonstrate three strategies of this type, where molded relief structures in these photopolymers represent (i) fine (<1 μm) features that serve as the phase masks for their own exposure, (ii) coarse features (>1 μm) that are used with phase masks to provide access to large structure dimensions, and (iii) fine structures that are used together phase masks to achieve large, multilevel phase modulations. Several examples are provided, together with optical modeling of the fabrication process and the transmission properties of certain of the fabricated structures. Lastly, these approaches provide capabilities in 3D fabrication that complement those of other techniques, with potential applications in photonics, microfluidics, drug delivery and other areas.

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TYPE Journal Article YEAR 2007
OSTIDOI

Tilted logpile photonic crystals using the LIGA technique

Proceedings of SPIE - The International Society for Optical Engineering

Williams, John D.; Arrington, C.; Sweatt, W.C.; Peters, David; El-Kady, Ihab F.; Ellis, A.R.; Verley, Jason C.; Mccormick, Frederick B.

The LIGA microfabrication technique offers a unique method for fabricating 3-dimensional photonic lattices based on the Iowa State "logpile" structure. These structures represent the [111] orientation of the [100] logpile structures previously demonstrated by Sandia National Laboratories, The novelty to this approach is the single step process that does not require any alignment. The mask and substrate are fixed to one another and exposed twice from different angles using a synchrotron light source. The first exposure patterns the resist at an angle of 45 degrees normal to the substrate with a rotation of 8 degrees. The second exposure requires a 180 degree rotation about the normal of the mask and substrate. The resulting pattern is a vertically oriented logpile pattern that is rotated slightly off axis. The exposed PMMA is developed in a single step to produce an inverse lattice structure. This mold is filled with electroplated gold and stripped away to create a usable gold photonic crystal. Tilted logpiles demonstrate band characteristics very similar to those observed from [100] logpiles. Reflectivity tests show a band edge around 5 μm and compare well with numerical simulations.

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TYPE Conference YEAR 2006
ScopusOSTI
Results 101–125 of 132
Results 101–125 of 132