Colloquium Schedule

Colloquium: Thursday, November 21st, 4:25 PM, Lewis Lab 316

Structural Influences on the Optical Properties Atomically Thin Metals

Kenneth L. Knappenberger, Jr.

The Pennsylvania State University
Recent advances in understanding structure-dependent optical properties of plasmonic 2D metals will be described. Using a process known as confinement heteroepitaxy, non-traditional plasmonic metals can be formed and kept stable for several months. A unique feature of metals formed in theis manner is the ability to generate materials that support both classical plasmon modes (in-plane) and discrete quantum excitations (out of plane). This multifaceted behavior results because the heteroepitaxy process generates 2-D metal films while confining axial growth to a few atomic layers, and hence, yielding inter-dimensional materials. As a result, both the quantum and classical aspects of these systems can be leveraged for tailoring material properties. In particular, inter-dimensional group lll metals (e.g. Ga and In) show extraordinary optical and electronic properties. In the case of gallium and indium, we observe nonlinear x2 values that are 103 larger than values typical for colloidal 3-D gold, and approximately 500x larger than for industrial standards, such as LiNbO3. These outstanding optical properties originate from multiple sources, including persistent plasmon coherence times, suppressed inter-band scattering by group III metals (w.r.t. gold), and intrinsic symmetry breaking at the metal-substrate interface. Many of these advances were made possible by the combined use of spatially resolved coherent nonlinear optical spectroscopy and correlative structural probes. Strategies for leveraging the unique properties of these inter-dimensional metals for controlled energy transfer will be described. Progress toward understanding energy transfer from these metals to molecular and semiconducting substrates will also be presented.

Click Here for full announcement

Physics and Astronomy Colloquia are usually scheduled for Thursdays at 4:25 PM in Lewis Lab room 316. Refreshments and snacks are available in the nearby coffee room at 4:00 PM.


Physics Colloquium Schedule for Fall 2019

Click on Title below for past or upcoming Announcements (where available), and Speaker name for website.        

August 29---
September 5V. DobrosavljevicFlorida StateLandau Theory for Disorder-Driven Metal-Insulator
September 12Ivan BiaggioLehigh University The Life and Times of Excitons in an Organic "Semiconductor": Fission, Fusion, Entanglement, Transport, and Dissociation
September 19Cyrus DreyerStony BrookThe Modern Theory of Polarization with a Twist
September 26Martin ZwierleinMITThe Sound of Fermions
October 3A.L. ExarhosLafayetteCreating, Controlling, and Characterizing Quantum Emission from Hexagonal Boron Nitride
October 10Edmund WebbLehigh UniversityMultiscale Modeling of the Human Blood Protein Von Willebrand Factor
October 17Eugene MeleU. PennAnomalous Velocity and Geometry in Wave Mechanics
October 24Berndt MuellerBrookhaven NLThe Unbearable Burden of Being Light: Emergence of Ordinary Matter from Quarks and Gluons
October 31Chueng JiNCS University Proton Puzzle
Novemebr 7Gabriel KotliarRutgers UniversityTowards a Predictive Theory of Strongly Correlated Electron Materials
November 14Karen KaszaColumbia UniversityUnderstanding and controlling the mechanical behavior of living tissues inside developing embryos
November 21K. L. KnappenbergerPenn State UniversityStructural Influences on the Optical Properties Atomically Thin Metals
November 28Thanksgiving Break--
December 5Javier Perez-MorenoSkidmore CollegeApplying Sum Rules to Interpret Experimental Data from Nonlinear Molecules