Optical properties of Ga from ab initio DFT-MD simulations (dotted lines) match experiment

1. Manipulating Surface Plasmons via Phase Transitions in Liquid MetalsTeri W. Odom, Northwestern University, DMR 1006380 Electronic circuits are increasingly constrained by the capabilities of metal interconnects to transport information. Surface plasmon polaritons (SPPs) are propagating electromagnetic waves that can potentially bridge the gap size between photonic (>100 nm) and nanoelectronics (<100 nm). To realize SPP photonic devices, there is a need for on-demand control of the plasmonic properties. We have dynamically manipulated SPPs in 1D Ga nanogratings via reversible solid-to-liquid phase transitions. Compared to the solid, the liquid phase exhibited higher SPP coupling efficiencies and narrower resonances. Exploiting the supercooling characteristics of Ga, we lowered the freezing point to access liquid plasmonic properties over a wide temperature range. Ab initio density functional theory-molecular dynamic (DFT-MD) simulations revealed why liquid properties were superior. Time (s) Reflectance map shows reversible switching of the plasmonic properties of liquid (L) and solid (S) Ga S.R.C. Vivekchand, C. Engel, S. Lubin, M. Blaber, W. Zhou, J.Y. Suh, G.C. Schatz, T.W. Odom, Nano Lett. 12, 4324 (2012) Optical properties of Ga from ab initio DFT-MD simulations (dotted lines) match experiment

2. Bringing Science to the ClassroomTeri W. Odom, Northwestern University, DMR 1006380 Members from the Odom group visit third and fourth grade students at a Chicago elementary school monthly. Graduate students teach scientific principles through very interactive, hands-on experiments. The topics explored in 2012 have included magnetism, chemical and physical reactions, heat and temperature, light, and sound. At the end of the school year, all of the elementary students are invited to a final demonstration held on the Northwestern University campus. Odom group members showcased experiments to over 200 students. (Top) Odom lab members and 3rd graders in April 2012 during the ‘Heat’ lab. Students learned how heat is transferred between objects and how to read thermometers. (Bottom) Students raising their hands to answer questions during a demonstration on chemiluminescence at the final show in May 2012.