University PhD Dissertation Defense of Anika Amir Kinkhabwala

[Anika Kinkhabwala]

Department of Applied Physics
University PhD Dissertation Defense



Large Single-Molecule Fluorescence Enhancements Produced by Gold Bowtie
Nanoantennas


Anika Amir Kinkhabwala

Research Advisor: Professor William E. Moerner

Refreshments at 3:00 p.m.

11 June 2010 @ 3:15 p.m.

Location: Applied Physics Building, Room 200



ABSTRACT
Plasmonic nanoantennas can concentrate light beyond the diffraction limit
and create highly enhanced local fields, leading to increased Raman
scattering and, in some cases, increased fluorescence from nanoscale
emitters. Gold bowtie nanoantennas provide a highly enhancing structure that
is more controllable and amenable to integration than other geometries such
as sharp metal tips and colloids. We have enhanced a single molecule's
fluorescence by a factor of 1,300 by coupling it to a bowtie nanoantenna,
ten times higher than previously reported for any other plasmonic structure.
Electromagnetic simulations reveal that this enhancement is a result of
greatly increased absorption of light as well as a shortened excited state
lifetime, leading to enhancement of the intrinsic quantum efficiency by an
estimated factor of nine, despite additional non-radiative ohmic losses.
Measurements of enhanced single-molecule fluorescence for molecules both in
rigid polymers and in solution show that bowtie nanoantennas can be used for
high-contrast selection of single nanoemitters in crowded environments.
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