There has been a considerable effort recently in the development of planar chiral metamaterials. Owing to the lack of inversion symmetry, these materials have been shown to display interesting physical properties such as negative index of refraction and giant optical activity. However, the biosensing capabilities of these chiral metamaterials have not been fully explored. Ultrasensitive detection and structural characterization of proteins adsorbed on chiral plasmonic substrates was demonstrated recently using UV-visible circular dichroism (CD) spectroscopy. Second harmonic generation microscopy is an extremely sensitive nonlinear optical probe to investigate the chirality of biomaterials. In this study, we characterize the chiral response of chiral plasmonic metamaterials using second harmonic generation microscopy and CD spectroscopy. These planar chiral metamaterials, fabricated by electron-beam lithography, consist of right-handed and left-handed gold gammadions of length 400 nm and thickness 100nm, deposited on a glass substrate and arranged in a square lattice with a periodicity of 800nm.
We discuss the design and development of a slow-light spectrometer on a chip with the particular example of an
arrayed waveguide grating based spectrometer. We investigate designs for slow-light elements based on photonic
crystal waveguides and grating structures. The designs will be fabricated using electron-beam lithography and UV
photolithography on a silicon-on-insulator platform. We optimize the geometry of these structures by numerical
simulations to achieve a uniform and large group index over the largest possible wavelength range.
A theoretical model is proposed for describing the effective nonlinearity of surface plasmons supported by a
single interface between a metal and a linear dielectric (or a vacuum). The response to the polarization fields
driving the nonlinearity is modeled using a Green function formalism for surface optics. The theory is employed
to investigate the self-phase modulation of the single-interface surface plasmon. We discuss the possibility of
using surface plasmon self-phase modulation to estimate the value of the third-order nonlinear susceptibility of
metals through experimentation.
The amplification of surface plasmon polaritons in planar metallic waveguides via propagation through an
optically pumped dipolar gain medium incorporated into one of the claddings is discussed theoretically and
experimentally. Physically realisable arrangements based on the single-interface and on the thin metal film
are described. Experimental results are given, demonstrating amplification of the long-range surface plasmon-polariton
along a thin metal stripe at near infrared wavelengths using a dye gain medium. Low amplified
spontaneous emission noise into this mode is simultaneously observed.
This paper discusses two aspects of current interest in surface plasmon photonics: the surface
sensitivity of surface plasmon waveguides, and the amplification of surface plasmon-polaritons via
propagation through an optically pumped dipolar gain medium incorporated into one of the
claddings. Physically realisable structures are considered in both cases.
We present results of our work aiming towards the amplification of surface plasmon-polariton modes in long-range
waveguide structures. Such structures are formed by a thin gold stripe sitting on a silicon dioxide substrate. The
active medium consists of organic-dye molecules with emission wavelengths in the near infra-red region, dissolved
in dimethyl sulfoxide and ethylene glycol. The active solution is index matched to the substrate and serves as
upper cladding, forming a symmetric waveguide structure. The large gain coefficients that can be obtained
with organic dyes together with the low attenuation coefficients offered by symmetric long-range surface plasmo-polariton
waveguides make these structures good candidates to achieve net amplification in the near infra-red