A Precise Photometric Ratio via Laser Excitation of the Sodium Layer I: One-photon Excitation Using 342.78 nm Light

Abstract

The largest uncertainty on measurements of dark energy using type Ia supernovae is presently due to systematics from photometry; specifically to the relative uncertainty on photometry as a function of wavelength in the optical spectrum. We show that a precise constraint on relative photometry between the visible and near-infrared can be achieved in upcoming surveys (such as in LSST at the Vera C. Rubin Observatory) via a mountaintop-located laser source tuned to the 342.78 nm vacuum excitation wavelength of neutral sodium atoms. Using a high-power (500 W) laser modified from laser guide star studies, this excitation will produce an artificial star (which we term a "laser photometric ratio star," or LPRS) of de-excitation light in the mesosphere that is observable from the ground at approximately 20 magnitude (i.e., well within the expected single-image magnitude limit of LSST) at wavelengths in vacuum of 589.16 nm, 589.76 nm, 818.55 nm, and 819.70 nm, with the sum of the numbers of 589.16 nm and 589.76 nm photons produced by this process equal to the sum of the numbers of 818.55 nm and 819.70 nm photons, establishing a precise calibration ratio between, for example, the LSST r and z filters. This technique can thus provide a novel mechanism for establishing a spectrophotometric calibration ratio of unprecedented precision, from above most of the Earth's atmosphere, for upcoming telescopic observations across astronomy and atmospheric physics. This article is the first in a pair of articles on this topic. The second article of the pair describes an alternative technique to achieve a similar, but brighter, LPRS than the technique described in this paper, by using two mountaintop-located lasers, at optical frequencies approximately 4 GHz away from resonances at wavelengths in vacuum of 589.16 nm and 819.71 nm respectively.

The second article in this pair of articles is at arXiv:2010.08683 . This article has 14 pages & 7 figures. Both articles are published in MNRAS. This most recent arXiv version fixes a minor error in the caption of Figure 4

References in corpus (6)

• Observational Constraints on the Nature of the Dark Energy: First Cosmological Results from the ESSENCE Supernova Survey
• Supernova Constraints and Systematic Uncertainties from the First 3 Years of the Supernova Legacy Survey
• Report of the Dark Energy Task Force
• Toward 1% Photometry: End-to-end Calibration of Astronomical Telescopes and Detectors
• Crowded Field Galaxy Photometry: Precision Colors in the CLASH Clusters
• A Precise Photometric Ratio via Laser Excitation of the Sodium Layer II: Two-photon Excitation Using Lasers Detuned from 589.16 nm and 819.71 nm Resonances

Cited by in corpus (3)

• A Precise Photometric Ratio via Laser Excitation of the Sodium Layer II: Two-photon Excitation Using Lasers Detuned from 589.16 nm and 819.71 nm Resonances
• From atomic physics, to upper-atmospheric chemistry, to cosmology: A "laser photometric ratio star" to calibrate telescopes at major observatories
• Microwave transitions in atomic sodium: Radiometry and polarimetry using the sodium layer