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Maser Oscillation in a Whispering-Gallery-Mode Microwave Resonator

P. -Y. Bourgeois·N. Bazin·Y. Kersale·V. Giordano·M. E. Tobar·M. Oxborrow
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Abstract

We report the first observation of above-threshold maser oscillation in a whispering-gallery(WG)-mode resonator, whose quasi-transverse-magnetic, 17th azimuthal-order WG mode, at a frequency of approx. 12.038 GHz, with a loaded Q of several hundred million, is supported on a cylinder of mono-crystalline sapphire. An electron spin resonance (ESR) associated with Fe3+ ions, that are substitutively included within the sapphire at a concentration of a few parts per billion, coincides in frequency with that of the (considerably narrower) WG mode. By applying a c.w. `pump' to the resonator at a frequency of approx. 31.34 GHz, with no applied d.c. magnetic field, the WG (`signal') mode is energized through a three-level maser scheme. Preliminary measurements demonstrate a frequency stability (Allan deviation) of a few times 1e-14 for sampling intervals up to 100 s.

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P. -Y. Bourgeois, N. Bazin, Y. Kersale, V. Giordano, M. E. Tobar, M. Oxborrow. 2005-06-09. Maser Oscillation in a Whispering-Gallery-Mode Microwave Resonator. https://doi.org/10.1063/1.2137452

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