Fabrication of extremely smooth blazed diffraction gratings

High efficiency diffraction gratings are important in a variety of applications, such as optical telecommunications, lithography, and spectroscopy. Special interest has been placed on blazed diffraction gratings for their ability to enhance diffraction intensity at the specular reflection angle off the blazed facets. In this thesis I will report a novel process for fabricating extremely smooth blazed diffraction gratings with 200 nm-period. The blazed grating is fabricated using interference lithography and anisotropic etching, then replicated using nanoimprint lithography. This process was developed for fabricating the off-plane blazed diffraction gratings for the NASA Constellation-X x-ray space telescope. In order for x-rays to reflect effectively through grazing incidence reflection, the gratings will be coated with high atomic number materials, such as gold. Deposition of thin metal film often develops residual stress that adds out-of-plane distortion. In this thesis the out-of-plane distortions due to thin metal films are analyzed using wavefront aberration functions known as the Zernike polynomials. The thin film stress is proved to be linearly related to the change of the Z₂₁ Zernike coefficient. The anisotropic material properties of silicon are taken into account in the derivation, and a prediction of lattice dependent distortion is proposed.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2004

Author dc:creator

• Chang, Chih-Hao, 1980-

Advisor dc:contributor.advisor

• Mark L. Schattenburg and George Barbastathis.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/27056

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/27056