Scandium doped Tm:YAG ceramics and single crystals: Coherent and high resolution spectroscopy

We report a detailed study about the effect of Scandium (Sc3+) doping on the 3H6-3H4 transition in Tm3+:Y3Al5O12 ceramics at cryogenic temperature. Inhomogeneous, homogeneous linewidths and Zeeman lifetime as a function of the Sc3+ codoping are presented and compared to values obtained in single crystals. We demonstrate that Sc3+ can be used to increase the inhomogeneous broadening without being detrimental to coherence properties and spectral hole persistence. This controlled disorder therefore provides larger bandwidth for signal processing applications such as spectral analyzers and quantum information processing. Moreover, we show that opaque ceramics prepared by simple solid-state reaction exhibit a long coherence lifetime and even narrower inhomogeneous linewidths than single crystals. Opaque ceramics are very attractive for material development because they offer ease and low cost of fabrication and enable the study of a larger range of composition compared to single crystals. However we show that the manufacturing and the initial stoichiometry of the ceramics have a significant impact on the inhomogeneous broadening.