Optical manipulation of nanoparticles and biomolecules in sub-wavelength slot waveguides.

The ability to manipulate nanoscopic matter precisely is critical for the development of active nanosystems. Optical tweezers are excellent tools for transporting particles ranging in size from several micrometres to a few hundred nanometres. Manipulation of dielectric objects with much smaller diameters, however, requires stronger optical confinement and higher intensities than can be provided by these diffraction-limited systems.

Optofluidic trapping and transport on solid core waveguides within a microfluidic device.

In this work we demonstrate an integrated microfluidic/photonic architecture for performing dynamic optofluidic trapping and transport of particles in the evanescent field of solid core waveguides. Our architecture consists of SU-8 polymer waveguides combined with soft lithography defined poly(dimethylsiloxane) (PDMS) microfluidic channels. The forces exerted by the evanescent field result in both the attraction of particles to the waveguide surface and propulsion in the direction of optical propagation both perpendicular and opposite to the direction of pressure-driven flow.

Generation of correlated photons in nanoscale silicon waveguides.

.We experimentally study the generation of correlated pairs of photons through four-wave mixing (FWM) in embedded silicon waveguides. The waveguides, which are designed to exhibit anomalous group-velocity dispersion at wavelengths near 1555 nm, allow phase matched FWM and thus efficient pair-wise generation of non-degenerate signal and idler photons.

High confinement in silicon slot waveguides with sharp bends.

Slot waveguides allow for high optical confinement in a planar optical waveguide. Here we show a method for maintaining this high degree of confinement in slot waveguides with sharp bends. This high confinement can be achieved by using an asymmetric slot-based structure, where the mode in the bend remains localized in the slot region.

Broad-band optical parametric gain on a silicon photonic chip.

Developing an optical amplifier on silicon is essential for the success of silicon-on-insulator (SOI) photonic integrated circuits. Recently, optical gain with a 1-nm bandwidth was demonstrated using the Raman effect, which led to the demonstration of a Raman oscillator, lossless optical modulation and optically tunable slow light. A key strength of optical communications is the parallelism of information transfer and processing onto multiple wavelength channels.

Tailored anomalous group-velocity dispersion in silicon channel waveguides.

We present the first experimental demonstration of anomalous group-velocity dispersion (GVD) in silicon waveguides across the telecommunication bands. We show that the GVD in such waveguides can be tuned from -2000 to 1000 ps/(nm*km) by tailoring the cross-sectional size and shape of the waveguide.

Ultrafast all-optical modulation on a silicon chip.

We experimentally demonstrate ultrafast all-optical modulation using a micrometer-sized silicon photonic integrated device. The device transmission is strongly modulated by photoexcited carriers generated by low-energy pump pulses. A p-i-n junction is integrated on the structure to permit control of the generated carrier lifetimes.