Ultraviolet Lasing Characteristics of ZnS Microbelt Lasers

Investigation on the room-temperature ultraviolet lasing characteristics of a single ZnS microbelt laser is presented. Lasing emission with peak wavelength at round 335 nm is observed from the hexagonal-wurtzite phase of ZnS microbelt under optical excitation. This is due to the Fabry-Perot resonance along the length of the microbelt. By studying the low-temperature and time-resolved photoluminescence, it is verified that the corresponding lasing characteristics are attributed to the excitonic optical gain process. Furthermore, the rectangular cross-sectional nanostructure of ZnS microbelt suppresses TM polarization for excitation power lower than ~1.4 times the threshold. Hence, ZnS microbelts can be a promising building block to realize ultraviolet semiconductor lasers with control of laser polarization.