Stabilizing a Fabry-Perot etalon to 3 cm/s for spectrograph calibration

Abstract

We present a method of frequency stabilizing a broadband etalon that can serve as a high-precision wavelength calibrator for an Echelle spectrograph. Using a laser to probe the Doppler-free saturated absorption of the rubidium D2 line, we stabilize one etalon transmission peak directly to the rubidium frequency. The rubidium transition is an established frequency standard and has been used to lock lasers to fractional stabilities of $<10^{-12}$, a level of accuracy far exceeding the demands of radial velocity (RV) searches for exoplanets. We describe a simple setup designed specifically for use at an observatory and demonstrate that we can stabilize the etalon peak to a relative precision of $<10^{-10}$; this is equivalent to 3 cm/s RV precision.

9 pages, 6 figures. Submitted to PASP

References in corpus (6)

• A laser frequency comb that enables radial velocity measurements with a precision of 1 cm s${}^{-1}$
• A new list of thorium and argon spectral lines in the visible
• Selection of ThAr lines for wavelength calibration of echelle spectra and implications for variations in the fine-structure constant
• Development of Fiber Fabry-Perot Interferometers as Stable Near-infrared Calibration Sources for High Resolution Spectrographs
• An Ultra-High Stability, Low-Noise Laser Current Driver with Digital Control
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