Calibration of an echelle spectrograph with an astro-comb: a laser frequency comb with very high repetition rate

Searches for extrasolar planets using precision radial velocity (PRV) techniques are approaching Earth-like planet sensitivity, however require an improvement of one order of magnitude to identify earth-mass planets in the habitable zone of sun-like stars. A key limitation is spectrograph calibration. An astro-comb, an octave-spanning laser frequency comb and a Fabry-Pérot cavity, producing evenly spaced frequencies with large wavelength coverage, is a promising tool for improved wavelength calibration. We demonstrate the calibration of a high-resolution astrophysical spectrograph below the 1 m/s level in the 8000-9000 Å and 4200 Å spectral bands.

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