Calibration of an astrophysical spectrograph below 1 m/s using a laser frequency comb

Abstract

We deployed two wavelength calibrators based on laser frequency combs (“astro-combs”) at an astronomical telescope. One astro-comb operated over a 100 nm band in the deep red (~ 800 nm) and a second operated over a 20 nm band in the blue (~ 400 nm). We used these red and blue astro-combs to calibrate a high-resolution astrophysical spectrograph integrated with a 1.5 m telescope, and demonstrated calibration precision and stability sufficient to enable detection of changes in stellar radial velocity < 1 m/s.