Colloquium: Jacob B. Khurgin

    Thursday, November 7, 2013 - 3:30pm - 5:00pm
    Meinel 307

    "How Small Can One Shrink a Laser?"


    There has been a recent surge in activity devoted to development of nanoscale lasers, particularly lasers employing surface-plasmon polaritons in metal dielectric structures. In my talk I will review recent efforts and present a theory to clearly outline the fundamental limits of how small the nanolaser can actually be.

    First I will show that, in order to go beyond diffraction limit, one absolutely must use metallic structures with associated loss. Then I will show that the lasing threshold of the single mode metal-semiconductor nanolaser is determined only by the photon absorption rate in the metal and exhibits very weak dependence on the composition, shape, size (as long as it is less than half a wavelength) and temperature of the gain medium. This threshold current is on the order of a few tens of microamperes for most semiconductor-metal combinations, which leads to unattainably high threshold current densities for a substantially subwavelength laser. I will also discuss the coherence properties of nanolasers, and their modulation speeds, which compare to that of a standard VCSEL. Therefore, in my view, surface plasmon emitting diodes, operating far below "spasing" threshold, may be a more viable option for chip-scale integrated nanophotonics.

    Speaker Bio(s): 

    Jacob B. Khurgin graduated with an M.S. in optics from the Institute of Fine Mechanics and Optics in St. Petersburg, Russia, in 1979. By 1980, he had emigrated to the U.S., where, to his great surprise, he almost immediately landed a job with Philips Laboratories in Briarcliff Manor, N.Y. For eight years, he worked with varying degrees of success on miniature solid-state lasers, II-VI semiconductor lasers, various display and lighting fixtures, X-ray imaging, and small appliances such as electric shavers and coffeemakers (for which he holds three patents). He simultaneously pursued graduate studies at the Polytechnic Institute of New York, which is now known as the New York University School of Engineering, from which he received a Ph.D. in electrical engineering in January 1987. A year later, prompted by a promotion to department manager, Khurgin's industrial career came to an abrupt end. He joined the electrical and computer engineering department of Johns Hopkins University, where, despite ever-present reservations about the place, he has settled down and currently serves as a professor.

    Khurgin's research topics have included an eclectic mixture of the optics of semiconductor nanostructures, nonlinear optical devices, lasers, optical communications, microwave photonics and rudimentary condensed matter physics. He currently works in the areas of mid-infrared lasers and detectors, phonon engineering for high frequency transistors, disorder in condensed matter physics, plasmonics, coherent secure optical communications, silicon photonics, cavity optomechanics, and slow light propagation. He has published six book chapters, 240 papers in refereed journals and 28 patents and has edited one book. Khurgin had held the position of visiting professor in an array of institutions of variable degrees of repute, including Brown University; the École Normale Supérieure and École Polytechnique in Paris, France; Princeton University; UCLA; and others. Khurgin is a fellow of the American Physical Society and the Optical Society (OSA).