ABSTRACT
The advent of nano-processing has led to the development of many
new technologies, a few of which are optical microscopy on the
nano-scale, optical near-field probes, single molecules as probes
for local fields, surface plasmonics, forces in confined fields and
others. Microwavemicroscopes formeasuring sub-wavelength sized
features embedded in a dielectric composite use a probe interacting
with the sample material via both evanescent and radiating fields
[1]. The optical properties of cavities are very sensitive to any
changes of the refractive index in their environment, making them
a promising solution for the detection of a number of important
viruses [2]. Optical forces can dominate in the tiny optical cavities
and they can provide a way of harnessing these forces, converting
them into micro-cavities that can mechanically adapt their geom-
etry [3]. Semiconductor quantum dots engineered to have both
fluorescent and paramagnetic properties offer great potential as
biological probes for imaging cellular activity. The probe is based on
a silica sphere incorporating the quantum dots with paramagnetic
nano-particles inside and target-specific groups attached to the
outside [4]. The ability to map the rheological characteristics
(mechanical properties such as elasticity and viscosity) of biological
tissues in vivo is important. A new optical method, Brillouin microscopy, with microscopic resolution is developed for this
purpose [5]. Optical antennas have the potential to become powerful
tools for nano-bio-imaging by enhancing the optical fields at this
miniature scale [6]. The development of optical trapping techniques
to control objects at the nano-scale is an important and challenging
endeavour [7]. Sound waves generated by light are the basis of
a sensitive medical imaging technique with applications to cancer
diagnosis and treatment [8]. It is suggested recently that nano-
particles of concentric structures with the cores made of ordinary
dielectrics and the shells of plasmonic materials, or vice versa, can
have resonant frequencies tuned by the ratio of the radii of the
core and the shell in a wide frequency range [9-11]. One of the
possible applications of the plasmonic materials is to build antenna
devices radiating and receiving electromagnetic energy at optical
frequencies – a very important concept for the construction of a
variety of probes. The high-Q factor, augmented sensitivity, and the
potential directional characteristics offered by the optical nano-
resonatorsmake them important components for chemical-and bio-
sensing applications.
