Simultaneous retrieval of fluidic refractive index and surface adsorbed molecular film thickness using silicon wire waveguide biosensors
Simultaneous retrieval of fluidic refractive index and surface adsorbed molecular film thickness using silicon wire waveguide biosensors
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DOI：
10.1364/oe.20.026969
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发表时间：
2012-11-19
期刊：
影响因子：
3.8
通讯作者：
Arai, Shigehisa
中科院分区：
文献类型：
--
作者：
Atsumi, Yuki;Xu, Dan-Xia;Arai, Shigehisa
对于硅线环形谐振器生物传感器，我们研究了同时恢复流体折射率Delta n(C)和表面吸附分子膜厚度Delta d(F)的变化。这可以通过同时监测在TE和TM极化下工作的传感器的共振位移来实现。虽然这一过程在原则上是简单的，但由于传感器波导横截面与其标称值在硅光子线器件中通常遇到的范围内的偏差，可能会引入显著的恢复误差。我们提出了一种利用测量的谐振器自由光谱范围(FSR)得到的群折射率来确定制作的波导尺寸的方法。我们进一步证明，利用实验测量的群折射率值，可以确定宽为+/-2 nm、高为+/-1 nm的波导尺寸。利用这种方法，利用光学可测量的参数，可以得到真实值的10%以内的精确度，从而使反演精度提高3倍以上。(C)2012年美国光学学会
For silicon wire based ring resonator biosensors, we investigate the simultaneous retrieval of changes in the fluidic refractive index Delta n(c) and surface adsorbed molecular film thickness Delta d(F). This can be achieved by monitoring the resonance shifts of the sensors operating in the TE and TM polarizations at the same time. Although this procedure is straightforward in principle, significant retrieval errors can be introduced due to deviations in the sensor waveguide cross-sections from their nominal values in the range commonly encountered for silicon photonic wire devices. We propose a method of determining the fabricated waveguide size using the group indices derived from measured free spectral range (FSR) of the resonators. We further demonstrate that using experimentally measured group index values, the waveguide size can be determined to accuracies of +/- 2 nm in width and +/- 1 nm in height. By using this procedure, Delta n(c) and Delta d(F) can be obtained to a precision of within 10% of the true values using optically measurable parameters, improving the retrieval accuracy by more than 3 times. (C) 2012 Optical Society of America