High resolution imaging and lithography using interference of light and surface plasmon waves

The resolution of optical imaging and lithography is limited by the wave nature of light. Studies have been undertaken to overcome the diffraction limit for imaging and lithography. In our lab, the standing wave surface plasmon resonance fluorescence (SW-SPRF) microscopy was developed. It is a combination of standing wave total internal reflection fluorescence (SW-TIRF), one of structured illumination techniques, with surface plasmon resonance (SPR). The SW-TIRF approach decreases the excitation wavelength by interfering two coherent light rays on the substrate and producing an evanescent standing wave field between the object and a high refractive index substrate. Evanescent standing wave illumination generates a sinusoidal interference pattern with 2n times higher-spatial frequency than original light, where n is the refractive index of the substrate allowing higher lateral resolution. Surface plasmon is generated by reflecting a light on the gold surface through the cover glass at a specific angle inducing collective excitation of electrons in the metal. The SPR contributes a better signal-to-noise ratio by inducing an enhanced evanescent electric field to excite fluorophores. With the SW-TIRF instrument, about 100 nm resolution was obtained. In this thesis, we aim to produce less than 50 nm resolution lithography and imaging using corrugated gold surface. The induction of surface plasmon wave with large wave number is made possible by the sinusoidal gold surface allowing wave number matching between the excitation light and the surface plasmon wave. This wave number matching requires proper optimization of parameters like grating constant, perturbation depth, incidence angle of the beam, and excitation wavelength. The fabrication of the corrugated gold surface would be done by e-beam etching with varying parameters.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2007

Author dc:creator

• Kim, Yang-Hyo

Advisor dc:contributor.advisor

• Peter T.C. So.

• 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

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/42303

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/42303