ZnO microwire lasing generated by mid-infrared laser pulses of various polarization

ZnO nanowire (NW) lasing driven by mid-infrared (MIR) laser pulses has attracted significant attention owing to its remarkable wavelength-independent lasing threshold and potential applications in diverse situations. However, the properties of MIR laser-driven ZnO microwire (MW) lasing are rarely studied when the wire diameter is increased from nanoscale to microscale, comparable to the wavelength of the driving laser. Here we experimentally measured the ZnO MW lasing driven by MIR laser with different polarizations. The measurements show that the laser polarized along the $c$ axis was more efficient for the lasing in MW with diameter smaller than the driving laser wavelength, while the polarization dependence was ambiguous when the MW diameter was greater than the driving laser wavelength. Through the modeling of the lasing process in ZnO MW, the observed polarization dependence is reproduced and can be attributed to the combined effect of the optical interference of the driving laser in the MW and the varying absorption properties of different MWs. The former is related to the MW diameter and the latter is sensitive to the sample growth condition. Our findings shed light on the feasibility of manipulation of the ZnO MW lasing.