"Ab Initio" Theory of Novel Micro and Nanolasers

Event Date: April 23, 2008
Speaker: A. Douglas Stone
Speaker Affiliation: Yale University
Sponsor: Nanotechnology Seminar Series
Time: 11:00 AM
Location: Birck Nanotechnology Center, Room 2001
Contact Name: Evgenii Narimanov
Contact Phone: (765) 494-6122
Contact Email: evgenii@purdue.edu
Open To: Acceptable for ECE694A

While the laser is one of the most important inventions of the past century and one of the most interesting and controllable non-linear systems in physics, there is surprisingly little predictive theory of lasing properties. Predicting lasing thresholds and output power far above threshold in the case of multiple interacting lasing modes presents a serious challenge to current theory. Many new laser designs have emerged as a consequence of modern micro and nanofabrication capabilities, for example micro cavity lasers, random lasers and photonic crystal lasers, and an improved analytic theory of lasing is necessary to understand and predict their properties. In this talk, I will sketch such a theory, which describes the open (non-hermitian) nature of a laser exactly in terms of biorthogonal modes, and treats the non-linear interactions to all orders. Thus, the theory can predict lasing properties quantitatively from knowledge of the dielectric function of the resonator and from basic properties of the gain medium, yielding an "ab initio" method to determine lasing states. The theory will be illustrated by application to one-dimensional edge-emitting lasers, two-dimensional micro disk and deformed disk lasers, and two-dimensional random lasers. The random laser in the diffusive regime has no measurable linear resonances at all, despite its sharp lasing lines in the presence of gain. Thus, its description is beyond the reach of conventional laser theory and the nature of its lasing modes was previously unknown.

A. Douglas Stone is currently Carl A. Morse Professor of Applied Physics and Physics at Yale University, and Director of the Division of Physical Sciences. He joined the Yale faculty in 1986, was promoted to Professor in 1990, and from 1997-2003 served as Chairman of the Department of Applied Physics. Previously, he obtained a Master's degree in Physics and Philosophy from Oxford in 1978 (where he was a Rhode's Scholar), a PhD in theoretical condensed matter physics from MIT in 1983, and did postdoctoral work at IBM (1983-1985).

His interests in theoretical physics span condensed matter and optical physics. His groundbreaking work with Patrick Lee on mesoscopic physics and universal conductance fluctuations is one of the most cited works in all of physics from the 1980's and was recognized by the McMillan Award of the University of Illinois at Urbana for “outstanding contributions to condensed matter physics”. For the past decade he has focused much of his research on optics, and specifically on micro cavity optics and laser physics, and holds three patents in these areas.  He is a Fellow of the American Physical Society, and a former Trustee and current General Member of the Aspen Center for Physics. He is currently writing a popular book about Einstein's contributions to quantum theory.