Towards lab-on-chip ultrasensitive ethanol detection using photonic crystal waveguide operating in the mid-infrared
Towards lab-on-chip ultrasensitive ethanol detection using photonic crystal waveguide operating in the mid-infrared
复制标题
中红外光子晶体波导在芯片上的超灵敏乙醇检测
DOI：
10.1515/nanoph-2020-0576
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发表时间：
2021-04
期刊：
影响因子：
7.5
通讯作者：
A. Rostamian;Ehsan Madadi-Kandjani;H. Dalir;V. Sorger;Ray T. Chen
中科院分区：
文献类型：
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作者：
A. Rostamian;Ehsan Madadi-Kandjani;H. Dalir;V. Sorger;Ray T. Chen
摘要由于在中红外光谱区具有独特的分子指纹，这一区域的吸收光谱近年来引起了广泛的关注。与商业红外光谱仪不同，商业红外光谱仪受到体积和成本密集型的限制，芯片上实验室红外光谱仪可以提供传感器的进步，包括原始传感性能，以及增强的便携性等用途。过去已经提出了几个用于芯片上乙醇检测的平台。然而，在室温下具有高灵敏度的选择性传感仍然是一个挑战。在这里，我们实验演示了一种基于多孔光子晶体波导的片内乙醇传感器，该传感器基于绝缘体上的硅基光子传感平台，提供了增强的光吸收，从而提高了灵敏度。这是通过设计和设计一种光学慢光模式来实现的，该模式具有ng=73的高群折射率，并在光子晶体波导结构的支持下在分析物中实现了模式功率的强烈局域化。这种方法包括协同设计范例，其独特的特点是导波通过待感测气体分析物的有效路径长度增加。这种基于PIC的芯片上实验室传感器是典型的，光谱设计为工作在3.4μm的中心波长，以匹配乙醇的峰值吸收。然而，慢光增强的概念是通用的，可以覆盖广泛的设计窗口和光谱范围，以检测多种气体物种。利用多孔光子晶体波导，我们展示了实现十亿分之一级气体检测精度的能力。当与量子级联激光器和探测器集成时，高灵敏度、可定制的光谱范围以及紧凑的外形使新型便携式光子传感器平台成为可能。
Abstract Thanks to the unique molecular fingerprints in the mid-infrared spectral region, absorption spectroscopy in this regime has attracted widespread attention in recent years. Contrary to commercially available infrared spectrometers, which are limited by being bulky and cost-intensive, laboratory-on-chip infrared spectrometers can offer sensor advancements including raw sensing performance in addition to utilization such as enhanced portability. Several platforms have been proposed in the past for on-chip ethanol detection. However, selective sensing with high sensitivity at room temperature has remained a challenge. Here, we experimentally demonstrate an on-chip ethyl alcohol sensor based on a holey photonic crystal waveguide on silicon on insulator-based photonics sensing platform offering an enhanced photoabsorption thus improving sensitivity. This is achieved by designing and engineering an optical slow-light mode with a high group-index of ng = 73 and a strong localization of the modal power in analyte, enabled by the photonic crystal waveguide structure. This approach includes a codesign paradigm that uniquely features an increased effective path length traversed by the guided wave through the to-be-sensed gas analyte. This PIC-based lab-on-chip sensor is exemplary, spectrally designed to operate at the center wavelength of 3.4 μm to match the peak absorbance for ethanol. However, the slow-light enhancement concept is universal offering to cover a wide design-window and spectral ranges towards sensing a plurality of gas species. Using the holey photonic crystal waveguide, we demonstrate the capability of achieving parts per billion levels of gas detection precision. High sensitivity combined with tailorable spectral range along with a compact form-factor enables a new class of portable photonic sensor platforms when integrated with quantum cascade laser and detectors.