Kita Derek M, Michon Jérôme, Hu Juejun
Opt Express. 2020 May 11;28(10):14963-14972. doi: 10.1364/OE.392486.
Waveguide-enhanced Raman spectroscopy (WERS) is a promising technique for sensitive and selective detection of chemicals in a compact chip-scale platform. Coupling light on and off the sensor chip with fibers however presents challenges because of the fluorescence and Raman background generated by the pump light in the fibers; as a result all WERS demonstrations to date have used free-space coupling via lenses. We report a packaged, fiber-bonded WERS chip that filters the background on-chip through collection of the backscattered Raman light. The packaged sensor is integrated in a ruggedized flow cell for reliable measurement over arbitrary time periods. We also derive the figures of merit for WERS sensing with the backscattered Raman signal and compare waveguide geometries with respect to their filtering performance and signal to noise ratio.
波导增强拉曼光谱（WERS）是一种很有前景的技术，可在紧凑的芯片级平台上对化学物质进行灵敏且选择性的检测。然而，由于光纤中泵浦光产生的荧光和拉曼背景，通过光纤将光耦合到传感器芯片上以及从芯片上耦合下来都存在挑战；因此，迄今为止所有的WERS演示都采用了通过透镜的自由空间耦合。我们报道了一种封装好的、光纤连接的WERS芯片，该芯片通过收集背向散射拉曼光在芯片上过滤背景。封装好的传感器集成在一个坚固的流通池中，以便在任意时间段内进行可靠测量。我们还推导了利用背向散射拉曼信号进行WERS传感的品质因数，并比较了不同波导几何结构的滤波性能和信噪比。
