Eli Yablonovitch

Abstract:  For 50 years, stimulated emission has been stronger and far more important than spontaneous emission. Indeed spontaneous emission has been looked down upon, as a weak effect. Now a new science of enhanced spontaneous emission is emerging, that will make spontaneous emission stronger and faster than any possible stimulated emission. This new science depends upon the use of nanoscale metallic optical elements, as antennas for spontaneous emission.

The overall increase in spontaneous emission rate can be roughly 8 orders of magnitude! Under favorable circumstances the spontaneous emission rate can be comparable to the optical frequency itself, which is unprecedented.

Among the applications will be: (1) Direct modulation of LED’s will extend above 1THz, far faster than the direct modulation speed of any laser. This may define the future of short distance data-communications technology. (2) Materials which do not fluoresce or luminesce, owing to strong non-radiative losses (i.e. most molecules), will now become spectroscopically accessible since their spontaneous emission will now compete favorably with non-radiative losses. This is expected to have revolutionary implications in basic biological research, since a local probe can be inserted into a cell to optically interrogate the molecules at the tip.

The lecture will provide the basic background in metal optics, and in optical frequency antennas required to understand the photo-physics of this new form of light emission.

Bio:  Eli Yablonovitch graduated with the B.Sc. degree in 1967 from McGill University, Montreal, Canada. He then received his Ph.d. degree in Applied Physics from Harvard University in 1972. He also has an honorary Ph.d. from the Royal Inst. of Tech., Stockholm Sweden in 2004. He worked for two years at Bell Telephone Laboratories, and then became a professor of Applied Physics at Harvard. In 1979 he joined Exxon to do research on photovoltaic solar energy. Then in 1984, he joined Bell Communications Research, where he was a Distinguished Member of Staff, and also Director of Solid-State Physics Research. In 1992 he joined the University of California, Los Angeles. Then in 2007 he became Professor of Electrical Engineering and Computer Sciences at UC Berkeley, where he is the Nortel Distinguished Professor.

Prof. Yablonovitch is a Fellow of the Optical Society of America and the American Physical Society. He is a Life Member of Eta Kappa Nu, and a Member of the National Academy of Engineering and the National Academy of Sciences. He has been awarded the Adolf Lomb Medal, the W. Streifer Scientific Achievement Award, the R.W. Wood Prize, and the Julius Springer Prize. In his photovoltaic research, Yablonovitch introduced the 4n2 light-trapping factor that is used commercially in almost all high performance solar cells.

Yablonovitch introduced the idea that strained semiconductor lasers could have superior performance due to reduced valence band (hole) effective mass. Today, almost all semiconductor lasers use this concept, including telecommunications lasers, DVD players, and laser pointers.

Yablonovitch is regarded as one of the Fathers of the Photonic BandGap concept, and coined the term "Photonic Crystal".