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Surface plasmon propagation along striped Gold structures has been investigated by collection-mode near-field microscopy, leading to map the field intensity at the structure surface and to assess the system behavior at the nanoscale.

Active plasmonics is an attractive emerging field in which the ability to control the surface plasmon polariton (SPP) propagation finds many applications such as realization of fully functional integrated photonic circuitry. We demonstrate both numerically and experimentally switching of the SPP transmission based on two different approaches namely the all-optical and electro-optical at telecom wavelengths. The plasmonic component consists of a compact and efficient SPP switch utilizing highly sensitive ring resonator which has high sensitivity to the refractive index changes. Fabrication was done via e-beam lithography utilizing advanced proximity corrections. The compenents were characterized via scanning near field optical microscope (SNOM) and leakage radiation microscopy respectively. Large modulations of upto ~ 40 % in SPP mode transmission were observed.

Optical antennas are passive device where fabrication designs decide operating frequency, gain and emission diagram. By introducing an electrically controllable load medium for the antenna, these characteristics can be externally controlled.

Strong coupling of molecular excitons and plasmons are used to manipulate molecular energy redistribution pathways on an ultrafast timescale. Ramifications for controlling energy decay pathways in molecules and excitons are discussed.

The locally enhanced optical field near a laser-irradiated metal tip is used as a local photon source for spectroscopic studies on nanoscale materials. Resolutions better than 20nm are achieved on individual single-walled carbon nanotubes.

The enhanced field near a laser irradiated metal tip leads to local second-harmonic generation thereby creating a highly confined photon source. This effect is applied to image the field distribution of strongly focused laser modes.