3 research outputs found
Selective Trapping or Rotation of Isotropic Dielectric Microparticles by Optical Near Field in a Plasmonic Archimedes Spiral
We demonstrate selective trapping
or rotation of optically isotropic
dielectric microparticles by plasmonic near field in a single gold
plasmonic Archimedes spiral. Depending on the handedness of circularly
polarized excitation, plasmonic near fields can be selectively engineered
into either a focusing spot for particle trapping or a plasmonic vortex
for particle rotation. Our design provides a simple solution for subwavelength
optical manipulation and may find applications in micromechanical
and microfluidic systems
Creating Optical Near-Field Orbital Angular Momentum in a Gold Metasurface
Nanocavities
inscribed in a gold thin film are optimized and designed to form a
metasurface. We demonstrate both numerically and experimentally the
creation of surface plasmon (SP) vortex carrying orbital angular momentum
in the metasurface under linearly polarized optical excitation that
carries no optical angular momentum. Moreover, depending on the orientation
of the exciting linearly polarized light, we show that the metasurface
is capable of providing dynamic switching between SP vortex formation
or SP subwavelength focusing. The resulting SP intensities are experimentally
measured using a near-field scanning optical microscope and are found
in excellent quantitative agreements as compared to the numerical
results
Creating Optical Near-Field Orbital Angular Momentum in a Gold Metasurface
Nanocavities
inscribed in a gold thin film are optimized and designed to form a
metasurface. We demonstrate both numerically and experimentally the
creation of surface plasmon (SP) vortex carrying orbital angular momentum
in the metasurface under linearly polarized optical excitation that
carries no optical angular momentum. Moreover, depending on the orientation
of the exciting linearly polarized light, we show that the metasurface
is capable of providing dynamic switching between SP vortex formation
or SP subwavelength focusing. The resulting SP intensities are experimentally
measured using a near-field scanning optical microscope and are found
in excellent quantitative agreements as compared to the numerical
results