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 × 15 mm × 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 5 T 2 → 5 E within the 3d 4 shell of Cr 2+ ions. Photoluminescence spectrum shows a relatively strong broad emission band centered at 4.1 μm with a width of 0.8 μm (FWHM) under 1770 nm excitation at room temperature and reveals effective Cr 2+ → Fe 2+ energy transfer process. Room temperature photoluminescence decay about 8 μs was measured. All the results indicate that Cr,Fe:ZnSe could achieve laser operation at 3.7–4.5 μm via Cr 2+ → Fe 2+ energy transfer using a more convenient laser pump source in the near IR region. [ABSTRACT FROM AUTHOR]