Beam Brooke M, Shallcross R Clayton, Jang Jinuk, Armstrong Neal R, Mendes Sergio B
Department of Chemistry, University of Arizona, Tucson, Arizona 85721, USA.
Appl Spectrosc. 2007 Jun;61(6):585-92. doi: 10.1366/000370207781269729.
A planar fiber-optic chip (FOC) has been developed using side-polished optical fibers and characterized for broadband absorbance and fluorescence detection of molecular films. FOC technology combines the sensitivity of an attenuated total reflection (ATR) element with the ease of use of fiber-optic-based spectrometers and light sources to create an improved platform for spectroscopic analysis of molecular adsorbates. A multi-mode optical fiber (core diameter = 50 mum, numerical aperture = 0.22, stepped refractive index profile) mounted in a glass V-groove block was side-polished to create a planar platform that allows access to the evanescent field escaping from the fiber core. For this generation of FOC technology, the exposed evanescent field has an interaction length of approximately 17.2 mm. The FOC platform was independently characterized through measurements of thin-film and bulk absorbing samples. The device performance was compared to the existing ATR technology and methods for increasing sensitivity of the FOC were investigated and validated. Additionally, we have demonstrated the ability of the FOC to both evanescently excite and collect fluorescence through guided modes of the optical fiber for a surface-confined luminescent semiconductor nanoparticle film (4 nm diameter, ligand capped, CdSe core). The FOC described here with a supported planar interface can facilitate the use of conventional planar deposition technologies and provide a robust planar platform that is amenable for incorporation into various sensor technologies.
一种平面光纤芯片（FOC）已利用侧面抛光的光纤开发出来，并对分子膜的宽带吸光度和荧光检测进行了表征。FOC技术将衰减全反射（ATR）元件的灵敏度与基于光纤的光谱仪和光源的易用性相结合，为分子吸附物的光谱分析创建了一个改进的平台。将一根安装在玻璃V型槽块中的多模光纤（纤芯直径 = 50微米，数值孔径 = 0.22，渐变折射率分布）进行侧面抛光，以创建一个平面平台，该平台能够接触到从光纤纤芯逸出的倏逝场。对于这一代FOC技术，暴露的倏逝场的相互作用长度约为17.2毫米。通过对薄膜和块状吸收样品的测量，对FOC平台进行了独立表征。将该器件的性能与现有的ATR技术进行了比较，并研究和验证了提高FOC灵敏度的方法。此外，我们还展示了FOC通过光纤的导模对表面受限的发光半导体纳米颗粒膜（直径4纳米，配体包覆，CdSe核）进行倏逝激发和收集荧光的能力。这里描述的具有支撑平面界面的FOC可以促进传统平面沉积技术的使用，并提供一个坚固的平面平台，适用于纳入各种传感器技术。
