BEGIN:VCALENDAR
VERSION:2.0
PRODID:icalendar-ruby
CALSCALE:GREGORIAN
X-WR-CALNAME:Physics Colloquium with Dr. Matthew White
X-WR-TIMEZONE:Eastern Time (US & Canada)
BEGIN:VEVENT
DTSTAMP:20260912T164310Z
UID:tag:localist.com\,2008:EventInstance_52022006913694
DTSTART:20260209T214000Z
DTEND:20260210T104000Z
DESCRIPTION:Metal-dielectric photonic crystal organic light emitting diodes
 : band structure\, defect engineering\, and topological states\n\n \n\nwit
 h Dr. Matthew White\nUniversity of Vermont\n\n \n\nABSTRACT: We investigat
 e the band structure of metal-dielectric photonic crystals comprising stac
 ked organic semiconductor microcavities with silver metal mirrors. Employi
 ng organic semiconductor dielectric layers allows the unit cells in the cr
 ystal to function as optoelectronic devices including OLEDs and photodetec
 tors\, whether addressed individually or collectively. Geometric variables
  and material composition are presented to tune the band structure and cor
 responding photonic wave functions within the crystal. When single defects
  are introduced into crystals\, individual unit cells with aperiodic dimen
 sionality of the organic dielectric layer\, the resulting mid-gap defect s
 tates are shown to hybridize with a photonic band at certain resonant dime
 nsions. The resonance of the defect cavity affects the transmittance of li
 ght through the device\, disrupting or enhancing the coupling between othe
 rwise resonant cavities. If the defect is periodic throughout the crystal\
 , the effects on band structure are very different.  We introduce a period
 ic defect to every other metal layer\, which doubles the size of the unit 
 cell and has previously been shown to induce a Peierls bandgap.  Defining 
 a ratio R of the thickness of the even numbered and odd numbered metal lay
 ers\, the condition R=1 results in no Peierls gap as the cavities are unif
 orm. We demonstrate that by varying that ratio from R<1 to R>1\, there is 
 a point where the band collapses resulting in topological edge states\, he
 avily localized in the two outer-most cavities.  Topological domain walls 
 are introduced within the bulk of a crystal with similar properties to sol
 iton-like domain walls in the Su-Schrieffer-Heeger model. \n\n \n\nBIOGRAP
 HY: Matthew White is an Associate Professor of Physics and the director of
  the Materials Science Graduate Program at the University of Vermont.  His
  research focuses on materials and devices for light harvesting and light 
 emission\, ranging from stability of commercial photovoltaic modules to na
 nostructured photonic devices.  Prior to joining UVM\, he was a postdoctor
 al researcher and then a fixed-term assistant professor in the Institute f
 or Physical Chemistry at the Johannes Kepler University in Linz\, Austria.
   He earned his PhD in Physics from the University of Colorado\, Boulder\,
  and a BS in Physics and Mathematics from the University of Washington.  \
 n\n \n\nWith refreshments from Panera Bread
GEO:44.479328;-73.198095
LOCATION:Votey Hall\, 303
SUMMARY:Physics Colloquium with Dr. Matthew White
URL;VALUE=URI:https://events.uvm.edu/event/physics-colloquium-with-dr-matth
 ew-white
CATEGORIES:Speakers and Lectures
END:VEVENT
END:VCALENDAR