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ESE Guest Seminar – “Coherent Control of Electromagnetic Waves via Tunable Chaotic Cavities”
November 14 at 10:30 AM - 11:30 AM
The theory of Coherent Perfect Absorption1 (time-reversed lasing) and Reflectionless Scattering Modes2 has shown that there always exist discrete solutions to scattering of electromagnetic waves in multiple-scattering geometries that achieve perfect transduction or perfect (reflectionless) impedance matching. In general these are transient (complex frequency) solutions, but, typically, with tuning of a one system parameter it is possible to achieve steady- state, reflectionless excitation of arbitrary systems. Here we focus on the case of reflectionless excitation of a lossless multiport/multi-channel system, and show3 that it is possible not only to eliminate reflection, but also to control the scattering into the output channels to perform routing or filtering functions. This is achieved by creating a degeneracy of d complex eigenvalues of the wave equation, tuned to the real frequency; and we find that the number of tuning parameters needed to achieve such routing at a given frequency to be 2(d+1). For heuristic reasons we expect an open low-loss wave-chaotic cavity with tunable scattering elements to be optimal for achieving routing functions, since such a cavity has overlapping, pseudo-random resonances, making it frequency agnostic, and easily reprogrammable. We will present the results of recent experiments4 and simulations3,4 of such a cavity that have confirmed this conjecture in the microwave frequency range. These systems are easily reprogrammable, making them uniquely effective for applications where frequency- agile performance is required and implying robustness to perturbations and defects in fabrication.
- “Coherent Perfect Absorbers: Time-reversed Lasers”, D. Chong, L. Ge, H. Cao, and A. D. Stone, Physical Review Letters, 105, 053901 (2010).
- “Theory of Reflectionless Scattering Modes”, William Sweeney, Chia Wei Hsu, and A. Douglas Stone, Phys. Rev. A, 2020, https://link.aps.org/doi/10.1103/PhysRevA.102.063511
- “Coherent Control of Scattering of Guided Waves”, in preparation, A. Alhulaymi, Pyvovar, P. Del Hougne, O. D. Miller, A. D. Stone.
- “Agile Free-Form Signal Filtering with a Chaotic-Cavity-Backed Non-Local Programmable Metasurface”, T. Faul, L. Cronier, A. Alhulaymi, A. D. Stone, P. del Hougne, submitted to Advanced Materials.
Douglas A. Stone
Carl A. Morse Professor of Applied Physics and Professor of Physics at Yale University, and Deputy Director of the Yale Quantum Institute
Professor A. Douglas Stone is Carl A. Morse Professor of Applied Physics and Professor of Physics at Yale University, and Deputy Director of the Yale Quantum Institute. He received his BA from Harvard University, an MA from Balliol College Oxford, (where he was a Rhodes Scholar), and his PhD from MIT in theoretical Condensed Matter Physics. He did pioneering work on mesoscopic electron physics and quantum chao in the 80’s and 90’s, co-discovering the existence of “Universal Conductance Fluctuations”, for which he received the McMillan Award for early career research in CM physics. He has worked primarily in Optical and Laser Physics for the past twenty years and has been recognized for his work on wave chaos and optics in random and complex media, including the proposal of chaotic cavity lasers and the development of Steady-state Ab Initio Laser Theory (SALT). In the related area of non-hermitian physics, his group pioneered the concept of time-reversed lasing (Coherent Perfect Absorption) and its generalization: Reflectionless Scattering Modes. He is a Fellow of the APS and of Optica, and he shared the 2015 Willis Lamb Award for Laser Science and Quantum Optics. His popular science book, Einstein and the Quantum: The Quest of the Valiant Swabian, was selected as science book of the year in 2013 by NPR and he is currently the Chair-Elect of the APS Forum on History and Philosophy of Science.