Characterization of a green astro-comb using a Fourier Transform Spectrometer

POSTER

Abstract

Searches for Earth-like exoplanets using precision stellar radial velocity (PRV) measurements require a precision and accuracy below 10 cm/s over several years. An astro-comb, the combination of a laser frequency comb with a coherent wavelength shifting mechanism (such as a doubling crystal or photonic crystal fiber) and a mode-filtering Fabry-Perot cavity (FPC), produces evenly spaced frequency markers with broad spectral coverage and is a promising approach to improved wavelength calibration for astrophysical spectrographs. The accuracy of an astro-comb relies on high-quality suppression of undesired comb lines by the FPC. Here we present a characterization of a green astro-comb using a high-resolution Fourier Transform Spectrometer (FTS) constructed in our laboratory. The FTS has an unapodized resolution of 125 MHz, which enables high resolution measurements of our 1 GHz repetition rate laser frequency comb after it has been filtered into a 20 GHz astro-comb. FTS measurements of the green astro-comb will reveal any systematic defects in our filtering process and help determine the ultimate accuracy of the astro-comb as a wavelength reference.

Authors

  • Alexander Glenday

    • Harvard-Smithsonian

  • Chih-Hao Li

    • Harvard-Smithsonian

  • Matthew Webber

    • Northeastern University

  • Nicholas Langellier

    • Harvard-Smithsonian

  • Gabor Furesz

    • Harvard-Smithsonian

  • Guoqing Chang

    • Massachusetts Institute of Technology

  • Li-Jin Chen

    • Massachusetts Institute of Technology

  • Hung-Wen Chen

    • Massachusetts Institute of Technology

  • Jinkang Lim

    • Massachusetts Institute of Technology

  • Franz Kaertner

    • Massachusetts Institute of Technology

  • David Phillips

    • Harvard-Smithsonian

  • Andrew Szentgyorgyi

    • Harvard-Smithsonian

  • Ronald Walsworth

    • Harvard-Smithsonian