Active Control of Terahertz Nanogap Device
Monday, May 21, Kemper Hall 1065, 11:00am-12:00pm
Speaker: Minah Seo
Director's Postdoctoral Fellow
Los Alamos National Laboratory
Terahertz technology is one of the successes can encompass a wide range of electronics and photonics, and contribute for its fundamental science as well as its potential impact on engineering applications in recent years. Development of metamaterials has supported various applications in this hidden frequency. Metamaterials are artificially structured materials, introduced to overcome the limit of natural dielectric responses and to get a desirable resonance tuning over broad bandwidths. The dielectric properties of these metamaterials, changeable by optical, electrical, or thermal means, with or without lateral patterns, are in turn used to control entire optical frequencies which further extend metamaterials performance. To develop tunable and actively controllable metamaterials with extremely high gain as electro-optic devices at terahertz frequencies was proposed. Terahertz wave transmission through subwavelength apertures is controlled by temperature and photo excitation driven refractive index change of substrate. Remarkably, the nanogap-patterned device allows the extinction to fall by four orders of magnitudes with completely shutting-off the resonance characteristics. This research will contribute on the highly sensitive terahertz sensing and detection technique.
Minah Seo received a M.S. (2005) and Ph.D. (2010) degrees in Physics from Seoul National University in Seoul, South Korea. Her thesis work for Ph.D. is about terahertz spectroscopy on plasmonic materials, semiconductor thin films and CNTs, and terahertz electromagnetic wave control by using actively controlled metamaterial, honored by outstanding doctoral dissertation award from Seoul National University in 2010. She has developed and accomplished a research on the topic of terahertz near field imaging of plasmonic structures, which inspired the further new project on the topic of terahertz-nano-plasmonics. Minah is currently Director’s postdoctoral fellow at Los Alamos National Laboratory, concentrating on ultrafast mid-to-far-infrared dynamics in individual semiconductor nanowires and in plasmonic metamaterials with high temporal and spatial resolution. She has authored over 30 refereed journal publications and two US and international patents.