No abstract

Forces arising from overlap between the guided waves of parallel, microphotonic waveguides are calculated. Both attractive and repulsive forces, determined by the choice of relative input phase, are found. Using realistic parameters for a silicon-on-insulator material system, we estimate that the forces are large enough to cause observable displacements. Our results illustrate the potential for a broader class of optically tunable microphotonic devices and microstructured artificial materials.

This paper reports a bidirectional fiber optic probe for the detection of surface enhanced Raman scattering (SERS). One facet of the probe features an array of gold optical antennas designed to enhance Raman signal, while the other facet of the fiber is used for the input and collection of light.

We have calculated the optically-induced force between coupled high-Q whispering gallery modes of microsphere resonators. Attractive and repulsive forces are found, depending whether the bi-sphere mode is symmetric or antisymmetric. The magnitude of the force is linearly proportional to the total power in the spheres and consequently linearly enhanced by Q. Forces on the order of 100 nN are found for Q=108, large enough to cause displacements in the range of 1mum when the sphere is attached to a fiber stem with spring constant 0.004 N/m.

Conventional lithographic methods (e.g. electron-beam writing, photolithography) are capable of producing high-resolution structures over large areas, but are generally limited to large (>1 cm 2 ) planar substrates. Incorporation of these features on unconventional substrates (i.e., small (<1 mm 2 ) and/or non-planar substrates) would open possibilities for many applications, including remote fiber-based sensing, nanoscale optical lithography, three-dimensional fabrication, and integration of compact optical elements on fiber and semiconductor lasers. Here we introduce a simple method in which a thin thiol-ene film strips arbitrary nanoscale metallic features from one substrate and is then transferred, along with the attached features, to a substrate that would be difficult or impossible to pattern with conventional lithographic techniques. An oxygen plasma removes the sacrificial film, leaving behind the metallic features. The transfer of dense and sparse patterns of isolated and connected gold features ranging from 30 nm to 1 μm, to both an optical fiber facet and a silica microsphere, demonstrates the versatility of the method. A distinguishing feature of this technique is the use of a thin, sacrificial film to strip and transfer metallic nanopatterns and its ability to directly transfer metallic structures produced by conventional lithography. Keywords pattern transfer; soft lithography; metal nanoparticles; nanofabrication; nanopatterning Nanostructures exhibit optical, 1 thermal, 2 electrical, 3 and magnetic 4 properties that differ from bulk materials. To harness these properties into functional devices, it is often important to control their size, shape, and position on a substrate. Electron-beam (e-beam) lithography has one of the highest resolutions of the lithographic techniques; it is often used to define nanostructures, as it can pattern arbitrary features over large areas (>1 cm 2 ) with a resolution of approximately ten nanometers. 5 E-beam patterning of non-planar surfaces (e.g. microspheres, lenses, cylinders, atomic-force microscope (AFM) tips) is challenging because these substrates are difficult to coat evenly with resist, and because their surfaces do not lie in a single focal-plane for the e-beam. E-beam patterning on extremely small planar substrates (e.g. fiber and laser facets, small pieces of substrates) is also challenging, as the edge bead resulting from the coating of resist can be as large as the sample itself. Evaporative e-beam resists that eliminate edge-beads have been developed, but require the use of an evaporation chamber with specific design and vacuum requirements, as well as specialized resist and developer. 6