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Abstract: |
Abstract: An optical frequency comb based on the
output of a mode-locked femtosecond laser can be a valuable tool
in a variety of spectroscopic studies and applications. The
frequency comb simultaneously provides excellent spectral
resolution and broad wavelength coverage across the visible and
near infrared. In this talk, I will describe our use of
optical frequency combs for two emerging spectroscopic
applications: (1) trace gas detection, and (2) calibration of
astronomical spectrographs. In the first case, the output of a
broadband frequency comb is used to directly measure the
spectral fingerprint of an absorbing gas. A novel
two-dimensional spectrometer permits rapid parallel readout over
5-10 THz with resolution limited only by the comb element
linewidth. Present efforts are aimed at developing similar
approaches in the 3-15 micron spectral region. The second class
of applications involves using atomically-stabilized frequency
combs with large (>10 GHz) mode spacing to provide a precise
calibration for astronomical spectrographs. Here we have
focused on generating a comb in the 1-2 micron range that would
be used in conjunction with a high-resolution spectrograph to
search for earth-like planets around M-class stars.
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