Applied Laser and Photonics Group, Faculty of Engineering, University of Applied Sciences Aschaffenburg, Würzburger Straße 45, 63743 Aschaffenburg, Germany.
eXcorLab GmbH, Industrie Center Obernburg, 63784 Obernburg am Main, Germany.
Sensors (Basel). 2021 Jun 3;21(11):3868. doi: 10.3390/s21113868.
In this article, we summarize our investigations on optimized 248 nm deep ultraviolet (UV) fabrication of highly stable epoxy polymer Bragg grating sensors and their application for biomedical purposes. Employing m-line spectroscopy, deep UV photosensitivity of cross-linked EpoCore thin films in terms of responding refractive index change is determined to a maximum of Δn = + (1.8 ± 0.2) × 10. All-polymer waveguide Bragg gratings are fabricated by direct laser irradiation of lithographic EpoCore strip waveguides on compatible Topas 6017 substrates through standard +1/-1-order phase masks. According near-field simulations of realistic non-ideal phase masks provide insight into UV dose-dependent characteristics of the Bragg grating formation. By means of online monitoring, arising Bragg reflections during grating inscription via beforehand fiber-coupled waveguide samples, an optimum laser parameter set for well-detectable sensor reflection peaks in respect of peak strength, full width at half maximum and grating attenuation are derived. Promising blood analysis applications of optimized epoxy-based Bragg grating sensors are demonstrated in terms of bulk refractive index sensing of whole blood and selective surface refractive index sensing of human serum albumin.
在本文中，我们总结了我们对优化的 248nm 深紫外（UV）制造高度稳定的环氧聚合物布拉格光栅传感器及其在生物医学应用方面的研究。采用 m-line 光谱学，确定了交联 EpoCore 薄膜在响应折射率变化方面的深 UV 光敏性最大可达Δn=+(1.8±0.2)×10。通过在兼容的 Topas 6017 衬底上使用标准的+1/-1 阶相位掩模对光刻 EpoCore 条形波导进行直接激光辐照，制造了全聚合物波导布拉格光栅。根据实际非理想相位掩模的近场模拟，深入了解了布拉格光栅形成的 UV 剂量依赖性特征。通过在线监测，在通过事先光纤耦合的波导样品进行光栅写入期间出现的布拉格反射，可以得出激光参数集的最佳值，以便在峰值强度、半最大值全宽和光栅衰减方面获得可检测的传感器反射峰。通过对全血的体折射率传感和人血清白蛋白的表面折射率传感，展示了优化的基于环氧的布拉格光栅传感器在血液分析方面的有前景的应用。
