Crystal Host Engineering for Transition Metal Lasers

摘要

Much progress has been made in power scaling mid-infrared lasers based on transition metal ions such as Cr~(2+), Co~(2+), and Fe~(2+) in zinc and cadmium chalcogenides. Still, the exploration of the physics of the devices is incomplete. In this work, we analyze absorption spectra from Fe~(2+) in several binary and ternary hosts at low temperatures. We examine the effect of host ion size and mass on the zero-phonon energy of these spectra and further develop our previous model for the upper state lifetime of Fe~(2+) in these materials. The effect of the relative disorder in the crystalline environment on the lasing characteristics of Cr:ZnS, Cr:ZnSe, Fe:ZnSe, and Fe:CdMnTe laser devices is explored. We show that increasing disorder of the crystal host is easily observed in broadening of the absorption spectra and the spectral lincwidth of the laser output, and the reduction in the portion of the emission spectrum accessible for mode locking. Practical design guidelines for laser devices are developed.