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

TL;DR

This paper demonstrates a near-infrared laser comb technology that achieves high stability and precision in radial velocity measurements, enabling the detection of Earth-sized exoplanets around M-type stars.

Contribution

It introduces a novel laser comb system in the near-IR with demonstrated stability and proof of concept for high-precision astronomical radial velocity measurements.

Findings

Achieved laser comb stability of <200 kHz.

Demonstrated Doppler precision of ~0.3 m/s.

Potential for <1 m/s radial velocity accuracy.

Abstract

We describe a successful effort to produce a laser comb around 1.55 $\mu$m in the astronomical H band using a method based on a line-referenced, electro-optical-modulation frequency comb. 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. This technology, when coupled with a high spectral resolution spectrograph, offers the promise of $<$1 m/s radial velocity precision suitable for the detection of Earth-sized planets in the habitable zones of cool M-type stars.