0000000000309043
AUTHOR
Harald Giessen
Novel plasmonic sensor design using plasmon-induced transparency
We introduce a novel sensor concept in the field of plasmonics, namely plasmon-induced transparency sensors. These sensors combine localized particle plasmon resonances with extremely small sensing volume with excellent sharp spectral resonances that show a good respose to refractive index changes of the surrounding environment. The principle is based on the plasmonic analog of electromagnetically induced transparency (EIT) between a radiative dipole and a nonradiative quadrupole antenna. This effect yields a spectrally narrow resonance within a broad localized particle plasmon resonance in the near-infrared spectral region [1, 2]. Using deposition of biotin and streptavidin, we demonstrate…
Towards the origin of the shear force in near-field microscopy
The shear force from a gold or a graphite sample acting on an approaching near-field optical probe is studied in detail. The adiabatic and dissipative contributions to the force are clearly distinguished by monitoring the amplitude as well as the phase of the tip vibration when the tip approaches the surfaces. We also take into account that not only the damping and the resonance frequency but also the mass of the system changes when the tip approaches the surface. The relative strength of the contributions to the force varies differently but characteristically with the distance of the two samples, starting at a much larger distance in the case of graphite. The adiabatic contribution is lar…
Planar metamaterial analogue of electromagnetically induced transparency for plasmonic sensing.
We experimentally demonstrate a planar metamaterial analogue of electromagnetically induced transparency at optical frequencies. The structure consists of an optically bright dipole antenna and an optically dark quadrupole antenna, which are cut-out structures in a thin gold film. A pronounced coupling-induced reflectance peak is observed within a broad resonance spectrum. A metamaterial sensor based on these coupling effects is experimentally demonstrated and yields a sensitivity of 588 nm/RIU and a figure of merit of 3.8.