Argonne Chemistry Research Areas

Nanophotonics - Experimental

Overview

A better understanding of the fundamental interactions between
nanoparticles in organized arrays is of paramount importance
for the development of nanoscale photonic devices. This is
because these interactions can serve as communication
mechanisms in nanometric regimes far below that of the
conventional semiconductor regime in use today. Fundamental
mechanisms of communication can involve transfer of energy
in the form of photons, charge, or spin. We are exploring
communication mechanisms through new spectroscopies and
the development of new nanostructures based on hybrid metal
nanoparticle/molecular components. Metal nanoparticles
possess plasmon modes whose intense local fields may be
useful for precise, photo-initiated processes in nano-structured
arrays. The creation of new organized nanostructures, coupled
with near-field optical technology, continues to reveal an
extraordinarily rich set of possibilities for producing coupled
plasmons that can delocalize in a unidirectional manner within
nanostructures. In a parallel development, recent spectroscopy
efforts on highly efficient organic fluorophores have produced
the first example of a room temperature, "single photon on
demand" source. We believe that combining the unique
nano-excitation properties of plasmons on metal nanoparticles
with fluorophores in organized structures will open entirely new
directions for both nanoscience and nanotechnology. Both
near-field scanning optical microscopies and far-field ultrafast
studies of metal colloids are being used for this work.

Staff

Gary P. Wiederrecht
Jeffrey Hall
Jasmina Hranisavljevic
Hicham, Ibn El Ahrach

Highlights

Apertureless Scanning Near-Field Optical Microscopy

Electron Beam Lithography and Nanofabrication (ppt)

Publications

**The following articles have been copyrighted by the
corresponding journal and any download must be made
in compliance with the journal's copyrights policies.

The Spatial Extension of the Field Scattered by Silver
Nanoparticles Excited near Resonance as Observed by
Apertureless Near-Field Optical Microscopy, G. A. Wurtz,
N. M. Dimitrijevic, and G. P. Wiederrecht, Jpn. J. Appl. Phys.
41, Part 2, No. 3B, L351-L354 (2002)

Photoinduced Charge Separation Reactions of J-Aggregates
Coated on Silver Nanoparticles, J. Hranisavljevic,
N. M. Dimitrijevic, G. A. Wurtz, and G. P. Wiederrecht,
J. Am. Chem. Soc. 124 (17), 4536-4537 (2002)

Contact: Gary Wiederrecht

Nanophotonics - Computational

Overview

Theoretical modeling of metallic nanostructures is carried out
to complement the experimental program described above,
as well as other nanophotonics experimental work at Argonne
and elsewhere. Much of this theoretical work involves
finite-difference time-domain (FDTD) simulations of light
interacting with nanostructured metallic systems. Both
two-dimensional and fully three-dimensional FDTD studies
of a variety of nanophotonics problems have been carried out.
This work attempts to understand and predict how light can
be confined, intensified, and manipulated on the nanoscale.
Also of interest is learning how molecular and nonlinear
optical processes can be stimulated by the intense fields that
are possible due to surface plasmon excitations.

Highlights