Can amplified spontaneous emission produce intense laser guide stars for adaptive optics?

TL;DR

This paper explores innovative methods to generate high-intensity laser guide stars for adaptive optics, focusing on amplified spontaneous emission and supercontinuum generation to improve AO system performance.

Contribution

It introduces two novel approaches—amplified spontaneous emission and supercontinuum lasers—for creating brighter laser guide stars in adaptive optics.

Findings

Amplified spontaneous emission can enhance LGS brightness.

Supercontinuum lasers may enable tilt sensing in atmospheric turbulence.

Potential excitation mechanisms include CW pumping, pulsed excitation, and plasma generation.

Abstract

Adaptive optics (AO) is a key technology for ground-based optical and infrared astronomy, providing high angular resolution and sensitivity. AO systems employing laser guide stars (LGS) can achieve high sky coverage, but their performance is limited by LGS return flux. We examine the potential of two new approaches that might produce high-intensity atmospheric laser beacons. Amplified spontaneous emission could potentially boost the intensity of beacons produced by conventional resonant excitation of atomic or molecular species in the upper atmosphere. This requires the production of a population inversion in an electronic transition that is optically-thick to stimulated emission. Potential excitation mechanisms include continuous wave pumping, pulsed excitation and plasma generation. Alternatively, a high-power femtosecond pulsed laser could produce a white-light supercontinuum high in the atmosphere. The broad-band emission from such a source could also facilitate the sensing of the tilt component of atmospheric turbulence.