Efficiency of Resonance and Cascade Schemes of Fluorescence Excitation in Atoms in Mesosphere for Laser Guide Star Creation. Part II. Iron Atoms

A laser guide star (LGS) is an essential part of the adaptive optics system of a ground-based optical telescope. The main limitation of sodium LGSs, formed on the basis of the resonant fluorescence of mesospheric sodium atoms is low brightness. To estimate a possibility of creating LGS based on the fluorescence of other metals in the mesosphere, the efficiency of fluorescence excitation schemes for iron atoms is calculated. The relative inverse fluorescence flux for transitions of iron atoms is calculated taking into account their content in the mesosphere and the transmittance of the atmosphere. The comparison with the results for sodium, nickel, and potassium atoms is made. Our results can be used for the development of adaptive optics systems with artificial reference sources for ground-based telescopes and mesospheric lidars.