We experimentally study the wavelength dependence of light propagation in a water suspension of lithium niobate microcrystalline particles.First,the ballistic transmission in the visible range of the suspension is measured.The nonlinear relationship is observed between the transport mean free path and the wavelength of the incident light.Secondly,we measure the coherent backscattering (CBS) of the sample at different wavelengths.The full width at half maximum of the CBS cone at 532 nm is about 1.24 times as large as that at 671 nm.The results indicate that the light with a long wavelength propagates further than the short wavelength light and the localization state of the short one is stronger.Finally,we investigate the light-controllable CBS experiments in the disordered materials of anisotropic scatterers,which show that the configuration of pump light with the longer wavelength and the probe light with the shorter wavelength performs better.
SHI FanZHANG XinZhengLI JunWANG PiDongXU YanYU XuanYiXU JingJun
Optical transmission at 532 nm from nonabsorbing disordered porous silicon dioxide has been studied experimentally. The transmission behaviors can be adjusted by filling the pores with liquids of different refractive indics, which are analyzed based on the theory of diffusion in a weak scattering regime. In our experiment, the transmission coefficient changes from a value less than 1% to one that is greater than 75%, that is, the opaque sample becomes transparent, which means that the transport mean free path of light within the material has been effectively adjusted. In addition, this method is a useful nondestructive method to derive the refractive index of an unknown bulk porous material.
