Competition of whispering gallery lasing modes in microwire with hexagonal cavity

The competition characteristics of different orders of whispering-gallery lasing modes in a single ZnO microwire with hexagonal cavity are investigated comprehensively. As the scale of the cavity increases, the mode competition would be emerging strongly. The high-order whispering-gallery mode (WGM) lasing is indicated to be transverse electric modes with polarization dependence of about 86%. In addition, the competition of whispering-gallery lasing modes depends strongly on the diameter of cavities and the excitation intensities due to the effects of spatial hole burning. The Power Fourier transfer gives the distinct path length of fundamental and high-order optical field. Moreover, the finite difference time domain presents the optical field of high-order WGM lasing that tends to be closer to the center of hexagonal cavities. Remarkably, the Purcell factors of WGM are enhanced strongly with the reduction in diameter of hexagonal cavities, and the maximum value of Fp approaches 20.