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| Three-Dimensional Photonic Crystals | |
|---|---|
| Description: | Nano 501 Seminar
Minghao Qi Abstract: A photonic crystal (PhCs) is typically a composite of a high-dielectric-constant material (e.g. Si) and a low-constant one (e.g. SiO2 or air), arranged periodically in space. Two dimensional examples include a hexagonal lattice of air holes drilled in a Si slab, or a set of Si rods at square lattice points. In some 3D configurations, photonic band gaps (PBGs) are formed such that photons over a certain frequency band cannot propagate in any directions. When the perfect periodicity is broken, e.g. a single hole filled or a single rod removed, point defects (or microcavities) are formed. Compared to cavities in 2D PhCs, the quality factors (Qs) currently achieved are lower. However, the Qs can be improved exponentially with increasing number of layers surrounding the cavities. The ultimate Q achievable is limited only by intrinsic material absorption. 3D PhCs also have the unique advantage that light can be confined in hollow microcavities. Another distinctive feature for a cavity in 3D PhCs is that the Q will not degrade with the presence of structural distortions. This makes it much more feasible to realize such cavities with nanofabrication. Finally, increasing the cavity Q in a 3D PhC does not require delocalization, or increase of mode-volume. Microcavities in 3D PhCs can be applied to explore a variety of fundamentally important physical phenomena. For example, high Q cavities with mode volumes approaching (1/2 λ/n)3 are ideal for studying cavity quantum electrodynamics (CQED). We show that with dynamic tuning of high-Q cavities, a scheme for on-demand single-photon emission could be realized in 3D PhCs. Bio: Minghao Qi received his B.S. degree in Chemical Physics from the University of Science and Technology of China. He received his M.S. and Ph.D. in Electrical Engineering from Massachusetts Institute of Technology in 1998 and 2005 respectively. He was a post-doctoral research associate in the Research Laboratory of Electronics at MIT before joining Purdue University as an assistant professor of Electrical and Computer Engineering in August 2005. |
| When: |
Wednesday, January 30 2008, 2:30pm - 3:30pm |
| Where: | Purdue University, EE 317 |
| Submitted by: Alicia Goodman | |