Holographic lithography boosts
plasmonic nanogap array production
HOBOKEN, N.J. – A technique based on
methods from holographic lithography has
been developed to demonstrate a new approach for scaling up the fabrication of
plasmonic nanogap arrays while simultaneously reducing costs and infrastructure.
A team led by Dr. Stefan Strauf, director of the NanoPhotonics Laboratory at
Stevens Institute of Technology, developed
the process to create uniform arrays of
metallic nanostructures. Existing nanogap
array production methods have low
throughput and are expensive and time-consuming to produce.
Plasmonic nanogap arrays have small
air gaps between them. By producing
strongly confined electrical fields in opti-
cal illumination, the air gaps allow the ar-
rays to be used in a number of applica-
tions, including ultrasensitive sensing and
photonic circuit miniaturization. Such sen-
sors could be used in high-resolution mi-
croscopy or to determine the presence of
specific chemicals or proteins at a single-
molecule level. Nanophotonic circuits,
which can transfer huge amounts of data,
are crucial to future-generation computing
power and to bringing about the exaflop
processing era.
Bottom left shows a four-beam interference lithography setup using blue light; upper left, the resulting 3-D
pattern. When the phase of one beam is changed, the trianglular lattice splits into a compound lattice featuring
a twin motive whose relative spacing can be tuned using beam polarization or exposure time. At upper right
is a scanning electron microscope image of the resulting nanogap template written into a photoactive polymer,
which can be backfilled with gold, resulting in the plasmonic nanogap array (lower right). Courtesy of Xi
Zhang and Stefan Strauf, Stevens Institute of Technology.
