Katharine B. Gebbie Young Scientist Award
Optical spectroscopy: frequency combs, radiocarbon, microcavities, and satellites
The work of myself and my collaborators has focused upon the application of novel highly sensitive spectroscopic techniques to present problems in atmospheric chemistry, atomic physics, and metrology. We have developed a wide range of cavity-enhanced instruments in which an optical cavity (i.e., a pair of highly reflective mirrors to form a resonator) serves to dramatically increase the instrument’s sensitivity by allowing for tens or even hundreds of thousands of transits through the absorbing medium. This has enabled spectroscopic measurements of radiocarbon (14C) for application areas such as dating and source apportionment. In addition, this instrumentation has allowed for the production of reference data to support atmospheric remote sensing by satellites. Further, we have developed approaches for the generation of optical frequency combs which allow for multiplexed, single-shot measurements of atomic and molecular gases. Finally, we have begun to apply these methods to the development of sensors based upon optical microcavities which offer exquisite sensitivity to external perturbations.
How can we find and use materials data to support our materials science?
One of the outcomes of the Materials Genome and other similar initiatives is an increase in the amount of materials science data now being generated and distributed. Even more is on the way. But how does a researcher find data or make data useful to someone else? How does one know where to look, judge the quality of the data, or decide whether it is applicable? This seminar will address several approaches to addressing these questions, including the development of a materials resource registry system to make finding materials data easier and work to facilitate the industrial use of molecular simulations of metallic materials. It will also describe efforts to look across the boundaries between research disciplines to find applicable analysis approaches while recognizing that each research problem is unique.
Visualizing Nanostructures with X-Rays
The semiconductor industry has revolutionized our way of life. It is hard to imagine life without all of our electronic gadgets. These electronics are made possible by tremendous technological advances in semiconductor manufacturing. The semiconductor industry has continuously shrunk the size of their transistors and memory cells for over 40 years following what is known as Moore’s Law. The devices have gone from macroscopic transistors nearly 1 mm in size to nanoelectronics under 20 nm in size. The latest generation of computer microprocessors have a minimum feature size of 14 nm, or about 30 silicon atoms across. This extreme scaling results in large increases in performance and power efficiency while decreasing the cost per transistor. In the near future, the industry will be manufacturing less than 10 nm features. These small features challenge the physical limits of current metrology tools. I will discuss the development of a new X-ray based measurement method with the potential to provide the needed resolution of the dimensions and shape of next generation semiconductor nanostructures. I will show examples of a series of nanostructures not possible to measure by other means.