Colloquia & Guest Speakers
Epsilon (and mu) Near Zero Materials – Photonics on Steroids?
Dr. Jacob Khurgin, Department of Electrical and Computer Engineering, Johns Hopkins University
Thursday, October 24, 2019
Bausch and Lomb 109
We examine the characteristics of optical materials with near zero real part of permittivity (ENZ), and compare them with other materials relying on resonance where Re(ε)~0 (e.g. plasmonics) or Re(1/ε)~0 (e.g. slow light, microresonators, e.t.c.). Despite being seemingly very diverse phenomena all of the resonant effects share a key common characteristics – slow group velocity. Consequently, whether one operates near a zero or a pole in optical response, one is bound to gain the same very useful enhancement of some properties such as nonlinearity, and, regrettably, the commensurate increase of loss and reduction in bandwidth. We show that all the purported enhancement of nonlinear properties of ENZ material comes from the fact that the group velocity is very low (“slow light effect”) while if in addition to ε~0 the magnetic permeability μ~0 as well (EMNZ materials), group velocity is high, and consequently, no enhancement of nonlinear optical properties ensues. As nonlinear or electro-optic materials ENZ’s do have an advantage – slow group velocity can be achieved in them without fabricating nanostructures such as resonators, photonic crystals etc. But this advantage needs to be weighed against high insertion loss. If time remains, we shall discuss “zero-index-materials” based on photonic crystals, which unlike ENZ offer no advantage whatsoever when it comes to switching and modulation.
Jacob B. Khurgin had graduated with MS in Optics from the Institute of Fine Mechanics and Optics in St Petersburg, Russia (now called something else) in the previous millennium (1979), and shortly thereafter, in 1980 he had emigrated to then hospitable US shores, where, to his own greatest surprise, he almost immediately landed what at a time seemed to be a meaningful job with Philips Laboratories of NV Philips in Briarcliff Manor, NY. There for 8 years he worked with intermittent success on miniature solid-state lasers, II-VI semiconductor lasers, various display and lighting fixtures, X-ray imaging, and, more important, on small appliances such as electric shavers and coffeemakers. Simultaneously he was pursuing his graduate studies at Polytechnic Institute of NY (nowadays elevated to NYU School of Engineering) where he had received PhD in Electrical Engineering in Jan. 1987. In Jan. 1988, prompted by a promotion to a Department Manager, Khurgin’s industrial career came to an abrupt end, and he had joined the ECE department of Johns Hopkins University, where, despite his ever present reservations about that place, he had settled down and is currently a Professor. His research topics over the years included an eclectic mixture of optics of semiconductor nanostructures, nonlinear optical devices, lasers, optical communications, THz radiation, microwave photonics, cavity optomechanics, slow light propagation, and rudimentary condensed matter physics. Currently he is working in the areas of infrared and THz frequency combs, laser cooling, microwave photonics, plasmonics, coherent secure optical communications, and silicon photonics. His publications include 8 book chapters, one book edited, 300 papers in refereed journals (some of them read and cited) and 40 patents (1 of them used). Prof Khurgin had held a position of a Visiting Professor in an array of institutions of variable degrees of repute – Princeton, UCLA, Brown, Ecole Normale Superieure (Paris), Ecole Polytechnique (Paris) , EPFL (Lausanne), ETH (Zurich) and so on. Prof. Khurgin is a Fellow of American Physical Society and Optical Society of America.
Location: B&L 109
Refreshments will be served.