Ultraviolet refractometry using field-based light scattering spectroscopy
Ultraviolet refractometry using field-based light scattering spectroscopy
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DOI：
10.1364/oe.17.018878
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发表时间：
2009-10-21
期刊：
影响因子：
3.8
通讯作者：
Feld, Michael S.
中科院分区：
文献类型：
--
作者：
Fu, Dan;Choi, Wonshik;Feld, Michael S.
在深紫外（UV）范围内精确的折射率测量对于生物学中蛋白质和DNA等生物分子的分离定量具有重要意义。这项任务要求很高，迄今尚未得到充分利用。本文报道了一种基于场的光散射光谱测量折射率的新方法，该方法适用于任何波长范围，既适用于溶液，也适用于具有明确形状的均匀物体，如微球。在260 ~ 315 nm波长范围内，用定量相显微镜测量了单个微球在均匀介质中的角散射分布。用Mie散射理论对观测到的散射分布进行最小二乘拟合，在已知先验条件下，可以确定球或浸没介质的折射率。用该方法测定了二氧化硅球和牛血清白蛋白溶液在深紫外区的折射率色散。提取了BSA的比折射率增量。目前折射率技术的典型精度为
Accurate refractive index measurement in the deep ultraviolet (UV) range is important for the separate quantification of biomolecules such as proteins and DNA in biology. This task is demanding and has not been fully exploited so far. Here we report a new method of measuring refractive index using field-based light scattering spectroscopy, which is applicable to any wavelength range and suitable for both solutions and homogenous objects with well-defined shape such as microspheres. The angular scattering distribution of single microspheres immersed in homogeneous media is measured over the wavelength range 260 to 315 nm using quantitative phase microscopy. By least square fitting the observed scattering distribution with Mie scattering theory, the refractive index of either the sphere or the immersion medium can be determined provided that one is known a priori. Using this method, we have measured the refractive index dispersion of SiO2 spheres and bovine serum albumin (BSA) solutions in the deep UV region. Specific refractive index increments of BSA are also extracted. Typical accuracy of the present refractive index technique is