Polariton-Mediated Coupling of Quasi-Degenerate Porphyrin Excitons

Aleksandr Avramenko, Aaron Rury

Wayne State University

Department of Chemistry

Abstract: When an ensemble of excitons strongly couples to single photons in a nano scale Fabry-Perot (FP) cavity, one drives the formation of hybrid light-matter states known as cavity polaritons. Previous studies have proposed polaritons formed from nearly degenerate Frenkel and Wannier-Mott excitons drives a photon-mediated entanglement of spatially separated material excitations across all light-matter coupling conditions. However, it remains unclear in what limit of near degeneracy these results exist and how to characterize similar entanglement for excitons stemming from highly disordered molecular ensembles. Previous studies show the Soret transition of porphyrin molecules enables the formation of robust molecular exciton cavity polaritons whose properties change relative to free space conditions. In this study, we form cavity polaritons using two quasi-degenerate porphyrin molecules, H2TPP, and CuTPP, by strongly coupling them to cavity photons in a multilayer FP resonator structure. We show that despite their apparent degeneracy in linear absorption spectra, the fraction of the H2TPP and CuTPP excitons in each polariton branch will vary as the cavity photon energy is tuned through its dispersion curve. The ability to tune the photonic and excitonic fraction of the polariton energy levels could be a pathway to create optical devices with selectively engineered optical properties.

Design of a Dynamic Liquid Z-Scan Spectrometer

By: Brian Clark

PI: Scott Sayres

University: Arizona State University

Abstract: This project revolves around the design and testing of a z-scan spectrometer capable of measuring the third order refraction index of liquids with the goal of studying suspended exotic nanoparticles in solution.  The measuring of high order refraction indexes is instrumental for studying the optical properties of materials and coatings.  Studying these properties for liquids and nanoparticles is less well understood than studying more mainstream solids and coatings, demonstrating a need for better designs of z-scan spectrometers working with these difficult mediums.  Several designs were built and tested throughout the research process, each achieving higher standards than the one before.  Reproducible data with suspended nanoparticles has not yet been collected, but the progress towards this goal is substantial.

Recycling Isocyanurates Via Dynamic Covalent Bonding

André B. Lagron¹, Kathryn K. Lee ¹, Ethan C. Nogle ¹, Leslie S. Hamachi ¹

¹Department of Chemistry and Biochemistry, California Polytechnic State University, San Luis Obispo, CA

Abstract: Isocyanurates are commonly used in the polymer industry because their high degree of crosslinking gives rise to superior mechanical properties. Due to their high degree of stability, isocyanurate bonds are not recyclable by any current industrial recycling methods. Dynamic covalent bonding has been used successfully to promote recyclability in similar polymer systems, including polyurethanes. We hypothesized that isocyanurates may be recycled using similar methods without sacrificing their mechanical properties. Isocyanurate dynamic bonding was investigated using small-molecule organic compounds, which allowed the reaction to be monitored via gas chromatography/mass spectrometry. Recycling industrial isocyanurate waste into consumer products would increase revenue for participating companies and reduce their environmental impact.

Material Model Identification of a Ti SiC Metal Matrix Nanocomposite Coating Using Micro Indentation and Multi Scale Simulations

Pouya Shojaei, Mohamed Trabia , Brendan O’Toole

Department of Mechanical Engineering, University of Nevada, Las Vegas

Abstract: While deposited thin film coatings can help enhance surface characteristics such as hardness and friction, their effective incorporation in product design is restricted by the limited understanding of their mechanical behavior. In this work, a Ti/SiC Metal Matrix Nanocomposite (MMNC) coating with a 5% weight of SiC nanoparticles was deposited over a Ti-6Al-4V substrate using the Selective Laser Melting (SLM). Material model was obtained using a combination of micro-indentation and meso/micro scale simulations. The meso-scale uniaxial compression finite element model was developed to obtain a material model of the coating. This material model was incorporated within an axisymmetric micro-scale model of the coating to simulate the indentation. The indentation depth result of the axisymmetric micro-scale model was compared with the micro-indentation testing to validate the composite coating material model. This comparison indicated that the proposed approach could be effective in capturing the post-indentation behavior of the composite coatings. This methodology can also be used for studying the response of composite coatings with different percentage of reinforcements.