Simultaneous measurement of refractive index and thickness by combining low-coherence interferometry and confocal optics
Simultaneous measurement of refractive index and thickness by combining low-coherence interferometry and confocal optics
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DOI：
10.1364/oe.16.005516
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发表时间：
2008-04-14
期刊：
影响因子：
3.8
通讯作者：
Lee, Byeong Ha
中科院分区：
文献类型：
--
作者：
Kim, Seokhan;Na, Jihoon;Lee, Byeong Ha
我们提出并证明了新的方法，使同时测量的相位指数，群指数，和光学透明的物体的几何厚度相结合的光学低相干干涉仪和共焦光学。低相干干涉仪给出了与厚度相关的群指数的信息，而共焦光学器件允许访问与样品的厚度相关的相位指数。为了将这些联系起来，设计了两种新的方法。在第一种方法中，色散引起的低相干包络线信号的加宽被利用，并且在第二种方法中，相位指数的频率导数通过在多个波长处进行共焦测量而直接获得。测量用八个不同的样品进行; B270、CaF 2、两个BK 7、两个熔融石英、盖玻璃和香烟盖膜。第一种方法和第二种方法的平均测量误差分别为几何厚度的0.123%和0.061%，相位指数的0.133%和0.066%，组指数的0.106%和0.057%。(C)2008年美国光学学会。
We propose and demonstrate novel methods that enable simultaneous measurements of the phase index, the group index, and the geometrical thickness of an optically transparent object by combining optical low-coherence interferometer and confocal optics. The low-coherence interferometer gives information relating the group index with the thickness, while the confocal optics allows access to the phase index related with the thickness of the sample. To relate these, two novel methods were devised. In the first method, the dispersion-induced broadening of the low-coherence envelop signal was utilized, and in the second method the frequency derivative of the phase index was directly obtained by taking the confocal measurements at several wavelengths. The measurements were made with eight different samples; B270, CaF2, two of BK7, two of fused silica, cover glass, and cigarette cover film. The average measurement errors of the first and the second methods were 0.123 % and 0.061 % in the geometrical thickness, 0.133 % and 0.066 % in the phase index, and 0.106 % and 0.057 % in the group index, respectively. (C) 2008 Optical Society of America.