随机介质内折射率分布对频谱特性的影响

采用时域有限差分法数值求解Maxwell方程组,分析了随机介质折射率分布对其频谱特性的影响.结果表明,折射率空间分布越无序,介质内的局域化现象会增强,被激发的模式会增多,频谱强度也会变大.而散射颗粒的折射率随时间的微小变化也会使介质内模式变多,且折射率变化幅度越大、频率越大、变化越快,模式的频谱强度也会相应增大.各向异...

Influence of Refractive Index Distribution on the Frequency Property in Random Media

The influence of refractive index distribution on the frequency property of optical modes in random media is analyzed by using the finite difference time domain method to numerically solve Maxwell equations. The results indicate that the number and the spectral intensity of the modes existed in random media is growing up with the increase of the randomness intensity of the refractive index distribution. The minor variety of the refractive index of scattering granules also can conduce to the increase of the number of the modes in random media. The spectral intensity of these modes is also determined by the excursion, frequency, and velocity of the variety of refractive index of scattering granules. Anisotropic random media can achieve the modulation of the refractive index in terms of time and space. The agreement between experimental observations and simulations is helpful in understanding the physical mechanism in random systems.