Extension of the broadband single-mode integrated optical waveguide technique to the ultraviolet spectral region and its applications.
Extension of the broadband single-mode integrated optical waveguide technique to the ultraviolet spectral region and its applications.
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宽带单模集成光波导技术向紫外光谱区的扩展及其应用。
DOI：
10.1039/c3an02201c
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Mendes,SergioB
中科院分区：
文献类型：
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作者：
Wiederkehr,RodrigoS;Mendes,SergioB
我们在此报告了单模集成光波导 (IOW) 光谱仪的制造、表征和应用，该光谱仪能够获取可见光和紫外光谱区低至 315 nm 的表面固定分子的光学吸收光谱。我们在紫外区域开发了一种低损耗单模电介质波导，该波导基于在高质量熔融石英衬底上通过原子层沉积 (ALD) 生长的氧化铝膜，并且通过我们设计/制造了由集成衍射光栅与大数值孔径的高度变形光束相结合形成的宽带波导耦合器，从而使单模 IOW 技术的 UV 扩展到更短的波长成为可能。作为所开发技术的应用，我们在这里利用其以 370 nm 为中心的 Soret 吸收带报告了细菌叶绿素 a 在不同界面上的表面吸附过程。固-液界面上不同化学成分对细菌叶绿素a的吸附和光谱特性的影响通过使用所开发的仪器获得的偏振UV-Vis IOW光谱来确定。单模IOW技术的光谱扩展到紫外区域是一个重要的进步，因为它使得能够对表面分子过程的关键特征（例如表面结合下的蛋白质展开和芳香族氨基酸基团的溶剂化）进行极其灵敏的研究，其光谱特征主要位于可见光谱以下的波长。
We report here the fabrication, characterization, and application of a single-mode integrated optical waveguide (IOW) spectrometer capable of acquiring optical absorbance spectra of surface-immobilized molecules in the visible and ultraviolet spectral region down to 315 nm. The UV-extension of the single-mode IOW technique to shorter wavelengths was made possible by our development of a low-loss single-mode dielectric waveguide in the UV region based on an alumina film grown by atomic layer deposition (ALD) over a high quality fused silica substrate, and by our design/fabrication of a broadband waveguide coupler formed by an integrated diffraction grating combined with a highly anamorphic optical beam of large numerical aperture. As an application of the developed technology, we report here the surface adsorption process of bacteriochlorophyll a on different interfaces using its Soret absorption band centred at 370 nm. The effects of different chemical compositions at the solid–liquid interface on the adsorption and spectral properties of bacteriochlorophyll a were determined from the polarized UV-Vis IOW spectra acquired with the developed instrumentation. The spectral extension of the single-mode IOW technique into the ultraviolet region is an important advance as it enables extremely sensitive studies in key characteristics of surface molecular processes (e.g., protein unfolding and solvation of aromatic amino-acid groups under surface binding) whose spectral features are mainly located at wavelengths below the visible spectrum.