Nanocrystalline Cr(2+)-doped ZnSe nanowires laser.

By using femtosecond laser pulses to ablate microsized targets that are dispersed in liquid media, nanocrystalline Cr(2+)-doped ZnSe nanowires have been successfully fabricated for the first time. The phase and stoichiometries of the original materials are preserved while the sizes are reduced down to 30-120 nm for these nanowires. X-ray diffraction results show that the products are nanocrystalline ZnSe with cubic sphalerite structure. Scanning electron microscope results indicate that the products be ZnSe nanowires. The nanowires are usually 30-120 nm in diameter and several tens of micrometers in length. Photoluminescence of the nanocrystalline Cr(2+)-doped ZnSe nanowires shows strong emission at around 2000-2500 nm under excitation of 1300-2250 nm wavelength at room temperature. By using the Cr(2+)-doped ZnSe multiple nanowires as the gain medium, mid-infrared oscillation at 2194 nm has been established. The oscillation wavelength of the multiple nanowires laser is 150 nm shifted to shorter wavelengths in comparison with that of microsized powder random laser.