Ultrafast wavelength-dependent lasing-time dynamics in single ZnO nanotetrapod and nanowire lasers

The ultrafast lasing dynamics of single zinc oxide (ZnO) nanotetrapods and nanowires are investigated by two-color femtosecond excitation/optical injection spectroscopy. The optical gain spectra obtained as a function of time and wavelength provide a means to distinguish the lasing from other emissions and are thus used to investigate the wavelength-dependent lasing dynamics in nanowires.