Cao H, Zhao Y G, Ho S T, et al. Random laser action in semiconductor powder [J]. Phys. Rev. Lett., 1999, 82(11):2278-2281.[2] Wiersma D S. The smallest random laser [J]. Nature, 2000, 406(7):132-133.[3] Cao H, Xu J Y, Seelig E W, et al. Microlaser made of disordered media [J]. Appl. Phys. Lett., 2000, 76(21):2997-2999.[4] Liu J, Liu H. Theoretical investigation on the threshold properties of localized modes in two-dimensional random media [J]. Mod. Opt., 2006, 53(10):1429-1439.[5] Lin Z X, Guo T L, Zhang Y G, et al. Study of the ZnO nanomaterial field-emission cathode array based on graphical growth [J]. Acta Optica Sinica (光学学报), 2010, 30(6):1739-1744 (in Chinese).[6] Wang J X, Ling C D, Han L. Nanocrystalline silicon film passively Q-switched laser diode pumped Nd:YAG/LBO blue laser [J]. Chin. J. Lasers (中国激光), 2010, 37(6):1564-1568 (in Chinese).[7] Meng X G, Fujita K J, Zong Y H, et al. Random lasers with coherent feedback from highly transparent polymer films embedded with silver nanoparticles [J]. Appl. Phys. Lett., 2008, 92(20):201112-1-3.[8] Ling Y, Cao H, Burin A L, et al. Investigation of random lasers with resonant feedback [J]. Phys. Rev. A, 2001, 64(6):063808-1-8.[9] Wang K J, Zhang Q Q, Lv J T, et al. Dependence of spectral width of TM-polarization lasing modes on pumping intensity in two-dimensional random media [J]. Acta Physica Sinica (物理学报), 2008, 57(5):2941-2945 (in Chinese).[10] Yu S F, Yuen C, Lau S P, et al. Zinc oxide thin-film random lasers on silicon substrate [J]. Appl. Phys. Lett., 2004, 84(17):3244-3246.[11] Fallert J, Dietz R J B, Sartor J, et al. Co-existence of strongly and weakly localized random laser modes [J]. Nat. Photon., 2009, 3(5):279-282.[12] Watanabe H, Oki Y, Omatsu T. Waveguide dye laser including a SiO2 nanoparticle-dispersed random scattering active layer [J]. Appl. Phys. Lett., 2005, 86(15):151123-1-3.[13] Yao K, Feng G Y, Yang L L, et al. Spatial Localized distribution of modes in two-dimension random medium [J]. Spectros. Spect. Anal.(光谱学与光谱分析), 2012, 32(10):2743-2748 (in Chinese).[14] Liang H K, Yu S F, Li X F, et al. An index-guided ZnO Random laser array [J]. IEEE, 2011, 23(8):522-524.[15] Fujiwara H, Hamabata Y, Sasaki K. Numerical analysis of resonant and lasing properties at a defect region within a random structure [J]. Opt. Exp., 2009, 17(5):3970-3977.[16] Cao H, Jiang X, Ling Y, et al. Mode repulsion and mode coupling in random lasers [J]. Phys. Rev. B, 2003, 67(16):161101-1-4.