par Vasily N. Astratov
Department of Physics and Optical Science
University of North Carolina
Charlotte, NC, USA
Résumé
Dielectric microspheres, with sizes on the order of several wavelengths, support high-quality whispering gallery (WG) modes and provide nonresonant focusing of light into tiny spots termed nanoscale photonic jets. In this talk, we review properties of more complicated multiple-cavity systems that are formed by microspheres assembled in chip-scale structures. The resonant optical properties of such systems can be engineered on the basis of tight-binding WG modes in photonic atoms. In practical systems of coupled cavities, the optical transport properties are strongly influenced by disorder effects, leading to scattering, localization, and percolation of light. Such structures can be used for developing coupled arrays of microlasers, ultracompact high-resolution spectrometers, and sensors. The nonresonant properties of such systems are connected through periodical focusing of light in chains and arrays of microspheres. In many biomedical and photonic applications the optical power is delivered by flexible hollow waveguides or multimode fibers. It is notoriously difficult to focus such multimodal beams. We show that integration of microspheres inside capillaries or hollow waveguides permit compact focusing of light from multimodal sources. Such structures are capable of focusing light in contact with tissue that can be used in ultraprecise laser tissue surgery.
Vasily Astratov is an associate professor in the Department of Physics and Optical Science at the University of North Carolina-Charlotte, joining the faculty in 2002. He received his Ph.D. degree from the A.F. Ioffe Physical-Technical Institute, St. Petersburg, Russia, in 1986. In 1993-1997 he headed a research group at the Ioffe Institute where he pioneered studies of opal photonic crystals. In 1997-2001 he has been a postdoctoral scholar at the University of Sheffield, UK, working on semiconductor microcavities, photonic crystals, and opals. He is a topical editor for the journal Optics Express since 2005. He has served as a technical committee member for CLEO/QELS 2006-07, ICTON 2007-10, and OECC/ ACOFT 08. He has been a member of the international DFG panel on photonic crystals in Germany in 2000-05 and a member of the NSF panels on photonic devices and technology in 2004-08. He is a recipient of a number of awards including Senior Visiting EPSRC Fellow Award in the UK in 2006 and Award of the Exchange Program adopted between Royal Society and Russian Academy of Sciences in 1996. His research has been funded through awards from NIH, NSF, and DOD. He has published more than 100 journal and conference papers in the areas of photonics and optoelectronics and his papers have been cited over 2000 times.
More information on Dr. Astratov and his research can be found on his website
Invitation : Nicolas Bonod (CLARTE)
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