科研之友
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摘要
Flexible photonic devices expand the application fields of photonics, but at the same time some new challenges come into being. For example, the distance from the neutral plane inside the multi-layer film stack to the detection surface is much larger than the penetration depth of the evanescent wave, an essential condition for biosensing, causing the evanescent wave to not reach the detection surface. Based on this point, a novel sandwich structure embedded in a micro-rigid body inside the cladding layer is presented in our paper. When the uniform loads are applied underneath the substrate, the strain distribution near the detection surface of the novel sandwich is greatly reduced compared with that of the conventional sandwich, while keeping the same order of magnitude at the other positions. It means that the effect of the strain-optical coupling behavior is greatly weakened without damaging the entire structure's original flexibility significantly. Through finite element simulation, we find that a wider, thinner micro-rigid body with a sleeker cross-section is preferred for the strain reduction. The strain near the detection surface can be reduced to only 10(-3) mu epsilon when the novel structure is subjected to a uniform load of 3 MPa. The resonance wavelength shifts caused by the strain-optical coupling effect are only 10(-4)-10(-3) pm according to 2D FDTD simulation, which can be completely neglected. The proposed device structure advances the accuracy of biosensing system based on flexible photonic devices and offers a promising approach to achieve the real-world application for biosensing detection.
- 出版日期2018-9
- 单位天津大学
