Università
Cattolica del Sacro Cuore – Sede di Brescia
Nano-localization of polarized
light: characteristics
and applications
Dott. Matteo Savoini
Abstract
Light polarization has been extensively studied since the beginning of
1800s; since then, a lot of different applications have been found dealing with
differently polarized states of light, the most known being LCD screens. All
these possible different applications have been extensively exploited in a
range of dimensions far from the smallest diffraction-limit areas
attainable.
With the development of nanotechnology, strong interest has been devoted
in the confinement of light beams in order to have higher and higher resolving
power, thus the possibility to study light-matter interaction on an extremely
small scale. So techniques like conventional optical microscopy nowadays employ
objective lens with high focusing power (defined by the numerical aperture),
allowing resolutions down to few hundreds nanometer,
with visible illumination light. Even better resolution can be attained by less
conventional techniques; like scanning near-field microscopy (SNOM), where
typically we have resolution of 100 nm. Even further improvement in the
resolution can be obtained with plasmonic nanoantennas, where the electric field can be confined to
dimensions down to 10/20 nm. Especially in the sub-diffraction limit, little
work has been done about the study of light polarization.
With the use of polarization preserving objectives, and/or
special near-field probes, we are now able to demonstrate that it is indeed
possible to implement polarization sensitive applications and analysis on areas
well below 1 μm2. In this way, a huge number of different
applications can be envisaged and studied ranging from polymeric science to
magnetic/metallic materials