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

Abstract

The spectroscopic characterization and energy transfer mechanism of iron-chromium co-doped ZnSe polycrystalline (Cr,Fe:ZnSe) were reported with dimension of 15mm×15mm×2mm obtained by controlled post-growth thermal diffusion method. The infrared absorption is characterized by a strong broad-band centered at 1770nm which can be attributed to the only spin-allowed transition 5T2→5E within the 3d4 shell of Cr2+ ions. Photoluminescence spectrum shows a relatively strong broad emission band centered at 4.1μm with a width of 0.8μm (FWHM) under 1770nm excitation at room temperature and reveals effective Cr2+→Fe2+ energy transfer process. Room temperature photoluminescence decay about 8μs was measured. All the results indicate that Cr,Fe:ZnSe could achieve laser operation at 3.7–4.5μm via Cr2+→Fe2+ energy transfer using a more convenient laser pump source in the near IR region.