Preparation, spectroscopic characterization and energy transfer investigation of iron-chromium diffusion co-doped ZnSe for mid-IR laser applications

The spectroscopic characterization and energy transfer mechanism of iron-chromium co-doped ZnSe polycrystalline (Cr,Fe:ZnSe) were reported with dimension of 15 mm x 15 mm x 2 mm obtained by controlled post-growth thermal diffusion method. The infrared absorption is characterized by a strong broad-band centered at 1770 nm which can be attributed to the only spin-allowed transition T-5(2) -> E-5 within the 3d(4) shell of Cr2+ ions. Photoluminescence spectrum shows a relatively strong broad emission band centered at 4.1 mu m with a width of 0.8 mu m (FWHM) under 1770 nm excitation at room temperature and reveals effective Cr2+ -> Fe2+ energy transfer process. Room temperature photoluminescence decay about 8 mu s was measured. All the results indicate that Cr,Fe:ZnSe could achieve laser operation at 3.7-4.5 mu m via Cr2+ -> Fe+ energy transfer using a more convenient laser pump source in the near IR region. (C) 2016 Published by Elsevier B.V.