Study of paramagnetic properties of Fe3+ ions to realizing Whispering Gallery Maser Oscillator

Abstract

In a preceding publication, we reported the experimental demonstration of maser oscillation at 12.04 GHz in a cryogenic sapphire whispering-gallery-mode resonator, where the resonator's dielectric ring contained a low concentration of paramagnetic Fe3+ ions within its monocrystalline sapphire lattice. Our preliminary measurements revealed a frequency stability of the order of 2.5 times 10-14 in a non-optimized design. In this paper, we report new measurements made on this same resonator to determine more precisely the main parameters affecting the dynamics of the Fe3+ ions when exposed to a microwave signal within their ESR bandwidth