Boston Chapter of the IEEE Photonics Society

Abstract:  It has been known for almost a century that photons carry momentum, giving light the ability to exert pressure.  However, in the macroscopic world, it is difficult to imagine a scenario where photon-momentum packs a punch.  Though, interestingly, as guided optical modes shrink to nanometer dimensions on integrated optical chips, optical forces can take a dominant role.  Conventionally, integrated optical elements are ‘frozen’ on a chip with little ability to move in response to such forces.  If, however, parts of a microcavity are designed to respond freely to the optical forces produced within, the microcavity, and its moving parts, can be controlled in truly unique ways.  For example, we illustrate that if a microcavity supports two modes (of differing symmetries) a tug-of-war can ensue between them, pushing the movable parts of the cavity in different directions.  When equilibrium is reached between the optical driving forces, the cavity’s moving parts become pinned, or ‘trapped’, in space at the picometer-level (or with sub-atomic precision), corresponding to an equally remarkable level of optical resonance control.  This form of optomechanical control is not only interesting because it enables tuning and manipulation of microcavity resonances over extensive wavelength ranges, all-optically; it can also be used to construct ‘smart’ optical elements which respond to optical stimulus in a ‘pre-designed’ manner.  As first illustration of a smart self-adaptive device, we describe an optomechanically variable microcavity design which enables dynamic tracking of an incident laser-signal.

Biography:  Peter Rakich received his bachelors in Honors Physics from Purdue University in 1999, after which he joined the Physics Department of MIT for his graduate studies.  There he earned his Doctorate in Physics under Professor Erich Ippen exploring novel physical phenomena in 1D, 2D and 3D photonic crystals, and developing new technologies for the advancement of high-confinement integrated photonics.  Since the completion of his Dissertation in 2006 he has worked as a Postdoctoral Associate under Professors Yoel Fink and Marin Soljacic developing novel light sources for the MID-IR and continuing to advance the field of integrated photonics.

Location:  MIT Lincoln Laboratory