A proposed laser frequency comb based wavelength reference for high resolution spectroscopy

High resolution spectroscopy is the foundation for many challenging astronomical observations. A highly precise, repeatable and stable wavelength calibration is especially essential for long term radial velocity observations. The two wavelength references in wide use for visible wavelengths, iodine absorption cells and thorium/argon lamps, each have fundamental limitations which restrict their ultimate utility. We are exploring the possibility of adapting emerging laser frequency comb technology in development at the National Institute of Standards and Technology in Boulder, Colorado, to the needs of high resolution, high stability astronomical spectroscopy.(1,2) This technology has the potential to extend the two current wavelength standards both in terms of spectral coverage and in terms of long term precision, ultimately enabling better than 10 cm/s astronomical radial velocity determination.