各向异性无序介质中随机激光的辐射特性的理论研究-物理电子学专业论文.docxVIP

II II Abstract Random laser is a novel and non-conventional laser which is based on the lasing phenomenon in the disordered gain media. The light amplification is carried out by scattering as feedback, and therefore the output characteristics are very unique. It has been in hot spotlight in laser physics with high potential in applications. Since random laser phenomenon was observed in experiments more than 10 years ago, researchers have done lots of experimental and theoretical work on it, mainly concerning random in space media. In this thesis we have researched random laser in the anisotropic random media. The main contents of this thesis are sμmmarized as follows: We combine Maxwell equations, rate equation and polarization equation to build the model for anisotropic random media according to the time dependent theory of random lasers, deduce the rotation matrix for reflection index transformation to principle axis in three dimension space, and solve the equations in nμmerical to analyze the characteristics of the two-dimensional random laser by FDTD method and VC programming. We simulate the TE mode and TM mode respectfully in two-dimensional random media and analyze the polarization and threshold property. The results show: without mode competition in the anisotropic media, the laser thresholds of TE mode and TM mode are similar. And there are more modes appearing in TM mode than in TE mode and the larger the random media is, the more of the modes appear. Besides, as the nμmber scatters decreases, the total of modes and threshold increase.. We introduce the time dependent theory of random lasers and share the reversed population in the gain media to simulate the laser phenomenon when mode competition happens between TE and TM modes in actual media, and compare the difference between the two polarization modes in the same random pattern, such as the modes’ frequency、the intensity of radiation、the value of the pμmping threshold and so on. We conclude that TE mod