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:
(1) bine 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.
(2) 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..
(3) We introduce the time dependent theory of random lasers and share the reversed
population in the gain media to simulate the laser phenomenon when petition
happens between TE and TM modes in actual media, pare 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 conclu
《中南山水名胜》科学技术教育文献 来自淘豆网www.taodocs.com转载请标明出处.