Physics & Astronomy Colloquium

3:30 PM, Friday, November 6, 2009
Room 155, Chem-Phys Building

Dr. Ron Walsworth
Harvard-Smithsonian Center for Astrophysics
Department of Physics, Harvard University

"Laser frequency combs for precision astrophysical spectroscopy''

Precision astrophysical spectroscopy is a crucial tool for cosmology and the search for extrasolar planets, but is currently limited by the stability and precision of existing wavelength calibration sources. I will describe our realization of a near-IR laser comb with up to 40 GHz line-spacing, generated from a 1-GHz repetition-rate source comb and Fabry-Perot filtering cavity, as an improved wavelength calibrator; integration and testing of this "astro-comb" with a telescope and precision spectrograph at the Whipple Observatory, directed at searches for extrasolar planets; and ongoing development of astro-combs operating in the visible. Astro-combs should allow more than an order-of-magnitude improvement in sensitivity to changes in Doppler-shifts and cosmological redshifts, with significant impact on many fields.

Refreshments will be served in CP 179 at 3:15 PM