Inhomogeneous Broadening

Galina Nemova

R. Houdré, Ross P. Stanley, Marc Ilegems

We study the effect of inhomogeneous broadening of the electronic state on vacuum-field Rabi splitting. The broadening has no effect on the size of the splitting and, in general, does not lead to an inhomogeneous broadening of the split states. From a spectroscopic point of view, these results have interesting consequences, since they allow the extraction of a homogeneous line in an inhomogeneously broadened system. \textcopyright{} 1996 The American Physical Society.

Peng-Jun Liang, Tian-Xiang Zhu, Yixin Xiao +4 more

The transportable quantum memory is a feasible solution for realizing the long-distance quantum communication, which requires a storage lifetime of the order of hours. The isotope-enriched 151Eu3+:Y2SiO5 crystal is a promising candidate for this application. However, its optical storage efficiency and spin storage lifetime are limited by the wide inhomogeneous linewidth. In this work, we successfully grow isotope-enriched 151Eu3+:Y2SiO5 crystals with varying doping concentrations by utilizing the Czochralski method. The optical inhomogeneous broadening and spin inhomogeneous broadening are measured by the optical absorption spectroscopy and optically detected magnetic resonance tests, respectively. Notably, in the undoped samples, we identify a baseline level of inhomogeneous linewidths, happening at (390 ± 15) MHz for optical inhomogeneous broadening and (4.6 ± 0.2) kHz for spin inhomogeneous broadening. Our findings reveal that the point defects, induced by the doping ions, significantly contribute to the inhomogeneous broadening. For every increase of 10–6 in doping concentration, the optical inhomogeneous broadening increases by 0.97 MHz, and the spin inhomogeneous broadening increases by 0.014 kHz. Furthermore, we discuss the influence of dislocations on inhomogeneous broadening and propose potential strategies to further mitigate these effects. These advancements are expected to promote the development of ultra-long-lifetime transportable quantum memory applications.

Charles P. Poole, Horácio A. Farach

Alan M. Portis

Albert T. Rosenberger

One characteristic normally used to distinguish inhomogeneous broadening from homogeneous broadening is the saturation behavior occurring when irradiation takes place at line center. The usual behavior found is that the absorption coefficient decreases as a negative power of 1 + I/Isat; a power of −1 indicates homogeneous broadening and a power of −½ denotes inhomogeneous broadening. It is shown here that, in the rate equation limit, this behavior is followed in most cases even though the homogeneous and inhomogeneous absorption profiles can have any line shape. The homogeneous line shape, in particular, need not be Lorentzian; its line center saturation behavior will be the same as that of a Lorentzian, however. If the inhomogeneous broadening is due to a distribution of atomic center frequencies, in the inhomogeneous limit the usual line center saturation behavior will be found no matter what the combination of homogeneous and inhomogeneous line shapes. However, if the broadening is inhomogeneous because of a distribution, among the individual atoms, in any property of the absorption profile other than center frequency (for example, the homogeneous linewidth), the saturation properties are not as simple, and in fact the inhomogeneous limit may not even exist.