Eli Yablonovitch

University of California, Berkeley

Primary Section: 31, Engineering Sciences
Secondary Section: 33, Applied Physical Sciences
Membership Type: Member (elected 2003)


Eli Yablonovitch is Director of the NSF Center for Energy Efficient Electronics Science (E3S), a multi-University Center headquartered at Berkeley. Yablonovitch introduced the idea that strained semiconductor lasers could have superior performance due to reduced valence band (hole) effective mass. With almost every human interaction with the internet, optical telecommunication occurs by strained semiconductor lasers. In his photovoltaic research, Yablonovitch introduced the 4(n squared) (“Yablonovitch Limit”) light-trapping factor, in worldwide use for almost all commercial solar panels. Based on his mantra that “a great solar cell also needs to be a great LED”, his startup company Alta Devices Inc. holds the world record for solar cell efficiency, now 29.1% at 1 sun. He is regarded as a Father of the Photonic BandGap concept, and he coined the term "Photonic Crystal". The geometrical structure of the first experimentally realized Photonic bandgap, is sometimes called “Yablonovite”. His startup company Ethertronics Inc., shipped over two billion cellphone antennas. He has been elected to the NAE, NAS, NAI, AmAcArS, and as Foreign Member, UK Royal Society.  Among his honors is the OSA Ives/Quinn Medal, the Benjamin Franklin Medal, the IEEE Edison Medal, the Buckley Prize of the American Physical Society, and the Isaac Newton Medal of the UK Institute of Physics.

Research Interests

Physics-Based Digital Optimization-  for Machine Learning, Control Theory, Backpropagation, etc. Optimization is vital to Engineering, Artificial Intelligence, and to many areas of Science.  Mathematically, we usually employ steepest-descent, or other digital algorithms.  But, Physics itself, performs optimizations in the normal course of dynamical evolution.  Nature provides us with the following optimization principles:  1. The Principle of Least Action;  2. The Variational Principle of Quantum Mechanics;  3. The Principle of Minimum Entropy Generation;  4. The First Mode to Threshold method;  5. The Principle of Least Time;  6. The Adiabatic Evolution method;  7. Quantum Annealing  In effect, Physics can provides machines which solve digital optimization problems much faster than any digital computer.  Of these physics principles, "Minimum Entropy Generation" in the form of bistable electrical or optical circuits is particularly adaptable toward offering digital Optimization.  For example, we provide the electrical circuit which can address the challenging Ising problem, binary magnet energy minimization.

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