4 research outputs found
Two-Color Laser Printing of Individual Gold Nanorods
We report on the deposition of individual
gold nanorods from an
optical trap using two different laser wavelengths. Laser light, not
being resonant to the plasmon resonances of the nanorods, is used
for stable trapping and in situ alignment of individual nanorods.
Laser light, being resonant to the transversal mode of the nanorods,
is used for depositing nanorods at desired locations. The power and
polarization dependence of the process is investigated and discussed
in terms of force balances between gradient and scattering forces,
plasmonic heating, and rotational diffusion of the nanorods. This
two-color approach enables faster printing than its one-color equivalent
and provides control over the angular orientation (±16°)
and location of the deposited nanorods at the single-nanorod level
Nanolithography by Plasmonic Heating and Optical Manipulation of Gold Nanoparticles
Noble-metal particles feature intriguing optical properties, which can be utilized to manipulate them by means of light. Light absorbed by gold nanoparticles, for example, is very efficiently converted into heat, and single particles can thus be used as a fine tool to apply heat to a nanoscopic area. At the same time, gold nanoparticles are subject to optical forces when they are irradiated with a focused laser beam, which renders it possible to print, manipulate, and optically trap them in two and three dimensions. Here, we demonstrate how these properties can be used to control the polymerization reaction and thermal curing of polydimethylsiloxane (PDMS) at the nanoscale and how these findings can be applied to synthesize polymer nanostructures such as particles and nanowires with subdiffraction limited resolution
Bending Gold Nanorods with Light
V-shaped
gold nanoantennas are the functional components of plasmonic
metasurfaces, which are capable of manipulating light in unprecedented
ways. Designing a metasurface requires the custom arrangement of individual
antennas with controlled shape and orientation. Here, we show how
highly crystalline gold nanorods in solution can be bent, one-by-one,
into a V-shaped geometry and printed to the surface of a solid support
through a combination of plasmonic heating and optical force. Significantly,
we demonstrate that both the bending angle and the orientation of
each rod-antenna can be adjusted independent from each other by tuning
the laser intensity and polarization. This approach is applicable
for the patterning of V-shaped plasmonic antennas on almost any substrate,
which holds great potential for the fabrication of ultrathin optical
components and devices
DNA-Assembled Nanoparticle Rings Exhibit Electric and Magnetic Resonances at Visible Frequencies
Metallic nanostructures can be used
to manipulate light on the subwavelength scale to create tailored
optical material properties. Next to electric responses, artificial
optical magnetism is of particular interest but difficult to achieve
at visible wavelengths. DNA-self-assembly has proved to serve as a
viable method to template plasmonic materials with nanometer precision
and to produce large quantities of metallic objects with high yields.
We present here the fabrication of self-assembled ring-shaped plasmonic
metamolecules that are composed of four to eight single metal nanoparticles
with full stoichiometric and geometric control. Scattering spectra
of single rings as well as absorption spectra of solutions containing
the metamolecules are used to examine the unique plasmonic features,
which are compared to computational simulations. We demonstrate that
the electric and magnetic plasmon resonance modes strongly correlate
with the exact shape of the structures. In particular, our computations
reveal the magnetic plasmons only for particle rings of broken symmetries,
which is consistent with our experimental data. We stress the feasibility
of DNA self-assembly as a method to create bulk plasmonic materials
and metamolecules that may be applied as building blocks in plasmonic
devices