Field of Study

The Vahala group performs research in optics at the meso-optic level i.e. we investigate optical properties of structures having dimensions in the micron size regime. Central to our research are micro-resonators. Of all resonant geometries micron-sized spherical dielectric resonators are unparalleled in terms of their ability to store and confine energy for long periods of time within meso-scale volumes. In the sphere light orbits near the surface where long confinement times (high-Q) effectively wraps a large interaction distance into a tiny volume. This characteristic makes them uniquely suited for studies of nonlinear coupling of light with matter. The electromagnetic modes - termed Whispering Gallery Modes (WGMs) -of these micro-spheres can be efficiently excited with a tapered optical fiber. Research in this area has been twofold. On the one hand we explore applications in optical telecommunication using these meso-scale structures . On a more fundamental level we investigate the physics which can be observed in these microstructures; Nonlinear effects like stimulated Raman Scattering, Stimulated Four Wave Mixing and Brillouin Scattering may be observed at extremely low input power levels and furthermore the conditions under which they can be observed are altered due to the confinement of the resonator. Additionally, micro-spheres are a candidate to investigate cavity QED effects, such as gain enhancement of nonlinear effects.

Research Areas:

- Micro-resonators for Optical Communication
- Nonlinear Optics in High-Q microresonators
- All Optical Logic

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last modified 9 March, 2007
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