Generating Ultrabroadband Deep-UV Radiation and Sub-10 nm Gap by Hybrid-Morphology Gold Antennas.

We experimentally investigate the interaction between hybrid-morphology gold optical antennas and a few-cycle Ti:sapphire laser up to ablative intensities, demonstrating rich nonlinear plasmonic effects and promising applications in coherent frequency upconversion and nanofabrication technology. The two-dimensional array of hybrid antennas consists of elliptical apertures combined with bowties in its minor axis. The plasmonic resonance frequency of the bowties is red-shifted with respect to the laser central frequency and thus mainly enhances the third harmonic spectrum at long wavelengths.

Low-loss, broadband and high fabrication tolerant vertically tapered optical couplers for monolithic integration of SiN and polymer waveguides.

A low-loss, broadband and high fabrication tolerant optical coupler for the monolithic integration of SiN and polymer waveguides is designed and experimentally demonstrated. The coupler is based on the adiabatic vertical tapering of the SiN waveguides. Low-loss operation is experimentally verified at both 976 and 1460-1635 nm wavelengths.

Optical antennas with sinusoidal modulation in width.

Small metal structures sustaining plasmon resonances in the optical regime are of great interest due to their large scattering cross sections and ability to concentrate light to subwavelength volumes. In this paper, we study the dipolar plasmon resonances of optical antennas with a constant volume and a sinusoidal modulation in width. We experimentally show that by changing the phase of the width-modulation, with a small 10 nm modulation amplitude, the resonance shifts over 160 nm.

A phased antenna array for surface plasmons.

Surface plasmon polaritons are electromagnetic waves that propagate tightly bound to metal surfaces. The concentration of the electromagnetic field at the surface as well as the short wavelength of surface plasmons enable sensitive detection methods and miniaturization of optics. We present an optical frequency plasmonic analog to the phased antenna array as it is well known in radar technology and radio astronomy.

Nanoimprint lithography for nanophotonics in silicon.

A novel inverse imprinting procedure for nanolithography is presented which offers a transfer accuracy and feature definition that is comparable to state-of-the-art nanofabrication techniques. We illustrate the fabrication quality of a demanding nanophotonic structure: a photonic crystal waveguide. Local examination using photon scanning tunneling microscopy (PSTM) shows that the resulting nanophotonic structures have excellent guiding properties at wavelengths in the telecommunications range, which indicates a high quality of the local structure and the overall periodicity.

Lambda/4 resonance of an optical monopole antenna probed by single molecule fluorescence.

We present a resonant optical nanoantenna positioned at the end of a metal-coated glass fiber near-field probe. Antenna resonances, excitation conditions, and field localization are directly probed in the near field by single fluorescent molecules and compared to finite integration technique simulations. It is shown that the antenna is equivalent to its radio frequency analogue, the monopole antenna.