UV lasing in powdered ZnO excited by nanosecond pumping

Investigations of UV spectra of powders and disordered films of ZnO excited by nanosecond pumping were conducted. Spectra of spontaneous emission were registered at 300 and 77 K. With some of our powdered samples we achieved lasing at 300 K. The threshold values of pumping energy density occurred to be higher than that under picosecond pumping approximately up to two orders of magnitude. Peculiarities of different samples lasing are demonstrated and discussed.