September 12, Vladimir Aksyuk, National Institute of Standards and Technology



12:30 PM in Room 901, 8 St. Mary’s Street
Coffee and cookies served at 12:15

Plasmonic and Photonic Mechanical Systems With Large Optomechanical Coupling: Measurements and Modeling

Abstract: Dielectric micro and nano structures such as waveguides, protonic crystals and microdisks enable efficient 2D and 3D confinement and manipulation of electromagnetic (EM) radiation in the visible and near-infrared frequency range. Alternatively, the large and predominantly negative dielectric constant of metals such as Au and Ag gives rise to EM excitations confined to metal/dielectic interfaces – surface plasmon polaritons (SPP) – as well as to localized plasmonic resonances on metallic nanoparticles and nanostructures. In both cases, due to the tight spatial confinement, the optical properties of such nanophotonic and nanoplasmonic structures can be exquisitely sensitive to mechanical motion or deformation of their constituent parts, giving rise to novel possibilities in optical sensing of mechanical motion and mechanical modulation of optical signals. This high optomechanical coupling also leads to the enhancement of the mechanical forces exerted on the nanostructures by the local EM radiation, and have been exploited for nearfield optical trapping, optomechanical excitation and even cooling of the mechanical motion to its quantum mechanical ground state. Additionally, resonant enhancement of a  localized EM mode is also exploited in both nanoplasmonic and nanophotonic devices. While optical quality (Q) factors of 10^6 to 10^8 can be achieved with dielectrics, in metals they are fundamentally limited by the intrinsic losses, even if the radiation loss is controlled. On the other hand, metals allow for much tighter EM mode confinement, e.g. with “lightning rod” structures and in narrow slot waveguides, with the correspondingly increased optomechanical coupling.

In this talk, I will describe modeling and design optimization of several nanophotonic and nanoplasmonic structures with high optomechanical coupling using a commercial multiphysics finite element package combining frequency domain EM solver with structural mechanics, parametrized geometry deformation and numerical optimization. I will show experimental results for two different types of nanophotonic-mechanical transducers incorporating high Q microdisk optical cavities on-chip and discuss our recent work on a plasmonic-mechanical modulator.

Biography: Vladimir Aksyuk is a Project Leader in the Center for Nanoscale Science and Technology at the National Institute of Standards and Technology. He received a B.S. in Physics from Moscow Institute of Physics and Technology and a Ph.D. in Physics from Rutgers University. Following research as a Member of Technical Staff and then Technical Manager at Bell Labs, he joined the research staff at NIST. Vladimir’s research focuses on the design and fabrication of novel optical MEMS systems. He holds more than 30 patents, and has published over 40 papers. In 2000 he received the Bell Labs President’s Gold Award, in 2005 was named among MIT Technology Review magazine’s TR35, and in 2008 received a Distinguished Alumni award for Early Career Accomplishments from Rutgers Graduate School. He is currently developing multiple projects in the use of optical MEMS and NEMS to address fundamental problems in nanomanufacturing.

Faculty Host:  David Bishop

Student Host: Jacob Trevino