B.S., Caltech, 1980; M.S., 1981; Ph.D., 1985.

phone: 626.395.2144
location: 234 Watson Laboratories
mail code: 128-95

Research Group |

Lightwave communications, ultrafast physics and application to high-speed information processing.

The recent research in the Vahala Group can be broken into several sub-groups:

• Ultra-High-Q toroidal microresonator: The development of the Ultra-high-Q silica toroidal microresonator has enabled many other devices such as High Q polymer resonators, four port couplers, and tunable microresonators. Additionally, recent results have shown pressure-driven mechanical oscillations present in the toroid.
• Non-linear Optics: Because of the very small mode volume and the very high-Q of silica microresonators, the power build-up is extremely large. This allows for studies of non-linearities in silica which would otherwise be extremely difficult.
• Sensing: Quality factors greater than 100 million in water have been achieved in water. These ultra-high-Q factors have enabled ultra-sensitive detection of heavy water heavy water.
• Rare-Earth Doping: By doping silica with rare earth elements, such as erbium, microlasers are able to be fabricated. We have collaborated with Prof. Albert Polman at FOM on Er+ ion implantation. Additionally, we have used Er+ doped sol-gel and CdSe/ZnS nanocrystals. We have collaborated with Prof. Harry Atwater at Caltech on CdSe/ZnS nanocrystal synthesis.
• Cavity Quantum Electrodynamics (cavity QED): Simulations have shown that UHQ microtoroids can provide a new and useful resonator platform for cavity QED experiments. In addition, the ability to couple optical power very efficiently to and from the resonator using a tapered optical fiber will be important. We are collaborating with Prof. Jeff Kimble’s group in the Caltech Physics Department to experimentally demonstrate strong coupling between a microtoroid and a single cesium atom.