Hao Ye, Gao Wentao, Sun Zhijun
Opt Lett. 2018 Mar 1;43(5):1159-1162. doi: 10.1364/OL.43.001159.
In this work, we fabricated a metallic Fabry-Perot cavity, filled with a weakly scattering medium of unsintered solgel silica, on a glass substrate. We found anomalous asymmetric resonance reflection spectra of this structure, besides the effects of scattering loss in cavity. The asymmetric reflection is shown to be dependent on the media on both sides of the cavity. It is thought that, as the weakly scattering medium locates between highly reflecting boundaries and the cavity length is far less than the mean free path of light in the medium, light scattering in the medium is enhanced at the resonance conditions and the scattering centers act as elementary sources emitting the scattered incoherent light to the outside of the cavity from both its ends. The asymmetric reflection then results from lossy total internal reflection of the scattered light at one of the boundaries, eventually leaking to the outside of the cavity with the higher index and contributing to the measured backside reflectance.
在这项工作中，我们在玻璃衬底上制作了一个金属法布里-珀罗腔，腔内填充未烧结的溶胶-凝胶二氧化硅这种弱散射介质。除了腔体内的散射损耗效应外，我们发现了这种结构异常的非对称共振反射光谱。结果表明，非对称反射取决于腔体两侧的介质。据认为，由于弱散射介质位于高反射边界之间，且腔体长度远小于光在介质中的平均自由程，在共振条件下介质中的光散射会增强，散射中心充当基本光源，从腔体两端向腔体外发射散射的非相干光。然后，非对称反射是由散射光在其中一个边界处的有损耗全内反射导致的，最终以较高折射率泄漏到腔体外，并对测量的背面反射率有贡献。
