Demonstration of a Near-IR Laser Comb for Precision Radial Velocity Measurements in Astronomy

We describe a successful effort to produce a laser comb around 1.55 μm in the astronomical H band (1.5-1.8 μm) using a method based on a line-referenced, electrooptical-modulation frequency comb (LR-EOFC). We discuss the experimental setup, laboratory results and proof of concept demonstrations at the NASA Infrared Telescope Facility (IRTF) and the Keck-II telescope. The laser comb has a demonstrated stability of < 200 kHz, corresponding to a Doppler precision of ∼ 0.3 m s−1. This technology, when coupled with a high spectral resolution spectrograph, offers the promise of ∼ 1 m s−1 radial velocity precision suitable for the detection of Earth-sized planets in the habitable zones of cool M-type stars. ar X iv :1 50 1. 02 50 9v 1 [ as tr oph .I M ] 1 1 Ja n 20 15