Events

In spin transfer devices a dc electric current is capable of exciting stable precession states of the magnetic moment. These auto-oscillations are powered by the current source and were found to have many remarkable properties, e.g., very narrow line widths. Precession regimes are thought to be useful for engineering nano-generators of microwave power on a chip.

Thermal chemical vapor deposition was used to grow graphene on copper substrates [1] and isotopic labeling (13C vs 12C [2]) was used to study how graphene grows on Cu [3]. Graphene holds potential as a transparent electrically conductive thin film [4a, b, c] and for electrical energy storage (e.g.,,graphene-based ultracapacitors [5]). Our top-down approaches [6,7] were the first to target obtaining individual layers of graphite obtained by micromechanical exfoliation.

Problems 1, 2 in the morning, problems 3, 4 in the afternoon

Problems 5 , 6 in the morning, Problems 7, 8 in the afternoon

Biological systems exhibit intrinsic heterogeneity due to subpopulation kinetics, non-correlated temporal behavior and complex dynamics. Studying single biological events unravels the fascinating subtleness of biological phenomena, which is unattainable in ensemble averaging. This is accomplished by using novel optical microscopy and fluorescence techniques to probe individual proteins, complexes, viruses or cells in real time and with superior accuracy.

I will address fundamental questions regarding biological interactions:

Mineral and compound semiconductors form the basis for most of the electronic and optoelectronic devices currently on the market. Their properties derive from the electronic band structure of highly crystalline materials. Recently, organic molecular and polymeric materials in optoelectronic applications are beginning to emerge in organic light emitting diodes (OLEDS), polymer photovoltaics and polymer electro-optic switches.

In this seminar I will discuss current and proposed research directions.
In order to create an effective research program in experimental biological physics, it is essential to undertake a multidisciplinary approach. This comprehensive approach is composed of three fundamental components:

1. Defining biological questions and systems of interest. I will refer to significant topics in DNA replication and repair, as well as viral infection and membrane proteins biology.

Graduates and undergraduates meet for lunch with Dr. Eli Rothenberg.

Science and technology are strongly influenced by light-matter interactions in materials that comprise real optoelectronic devices. The designs of these devices can be enhanced using knowledge of the fundamental electronic dynamics and dephasing processes. Ultrafast pulsed laser experiments provide a snapshot of these fundamental processes, and tailoring the excitation pulses allows for coherent control of the light-matter interactions.

Coherent optical control of optoelectronic, photonic and quantum electronic materials is useful because it elicits information about fundamental physical processes. It also providing better knowledge of how these materials behave when incorporated into nanoscale and quantum devices. Here, I demonstrate quantum interference between single and two-photon absorption pathways in semiconductors. This injected and controls transient currents that are detected by terahertz emission.

Graduate and undergraduate student lunch with Alan Bristow

Biomolecules perform fascinating functions essential for all life forms, including disease states upon perturbation or mutation. In order for existing biomolecular complexes to achieve optimal performances or to engineer new ones to execute targeted activities, a deep “bottom-up” understanding of the connection between the fundamental molecular mechanism and biological functions is required.

Observing the vibrational spectra of biomolecules in real time offers the exciting possibility to track ultrafast structural dynamic changes of the photoexcited chromophore if by stimulated Raman, or conformational dynamics of protein residues if extending into the IR regime and going multidimensional.

Undergraduate and graduate students meet with Chong Fang