Filterless Nondispersive Infrared Sensing using Narrowband Infrared Emitting Metamaterials
Filterless Nondispersive Infrared Sensing using Narrowband Infrared Emitting Metamaterials
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DOI：
10.1021/acsphotonics.0c01432
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发表时间：
2021-01-13
期刊：
影响因子：
7
通讯作者：
Caldwell, Joshua D.
中科院分区：
文献类型：
--
作者：
Livingood, Alyssa;Nolen, J. Ryan;Caldwell, Joshua D.
对于许多工业和制造业应用，检测和识别低浓度的有害气体和副产品是使用非色散红外（NND）传感器来执行的。这些简单的设备利用宽带IR发射器、热电堆检测器和调谐到感兴趣的分析物的振动共振的光谱窄带通滤波器。然而，这种滤波器制造昂贵，并且将NRF限制为仅在单个频率下操作，除非采用滤波轮，这显著地扩大了设备的尺寸和复杂性。在这里，我们创建一个纳米光子红外发射超材料（NIREM）的掺杂氧化镉薄膜上生长的图案化蓝宝石衬底（PSS），表现出窄带热发射。通过将足够窄的线宽发射器与简单的宽带检测器（诸如热电堆）耦合，可以在不需要窄带通滤波器的情况下复制NH3传感器的功能。与许多基于超材料的发射器不同，我们的设备在偏离表面法线0度至40度的角度下发射具有接近1发射率的p偏振光和s偏振光，而无需复杂且昂贵的光刻步骤。作为一个概念的证明，我们实现了这个NIREM的FTIR光谱仪内的CO2气体检测，表现出与传统的黑体/过滤器组合的性能相媲美。这表明，NIREM概念可以为NREM设备提供合适的即插即用替代品，因为它们可以以与现有技术相当或显著减小的形状因子来实现。原则上，通过结合被调谐为以不同频率发射的多个NIREM管芯，可以顺序地检测多个振动模式，使得该方法适合于鉴定和定量单个NNN 2 O3构型内的复杂分子。
For many industrial and manufacturing applications, detecting and identifying low concentrations of harmful gases and byproducts are performed using nondispersive infrared (NDIR) sensors. These simple devices utilize a broadband IR emitter, thermopile detector, and a spectrally narrow bandpass filter tuned to a vibrational resonance of the analyte of interest. However, such filters are expensive to fabricate and limit the NDIR to operation at only a single frequency, unless filter wheels are employed, which expand the size and complexity of the device considerably. Here, we create a nanophotonic infrared emitting metamaterial (NIREM) fabricated from thin films of doped CdO grown on patterned sapphire substrates (PSS) that exhibit narrowband thermal emission. By coupling a sufficiently narrow line width emitter with a simple broadband detector such as a thermopile, the functionality of the NDIR sensor can be replicated without the need for the narrow bandpass filter. Unlike many metamaterial-based emitters, our device emits both pand s-polarized light with near-unity emissivity at angles ranging from 0 degrees to 40 degrees off the surface normal without complicated and expensive lithography steps. As a proof of concept, we implement this NIREM for CO2 gas detection within an FTIR spectrometer, demonstrating performance comparable with a conventional blackbody/filter combination. This demonstrates that the NIREM concept can provide a suitable plug-and-play replacement for NDIR devices as they can be implemented in a form-factor commensurate or significantly reduced in comparison to the current state of the art. In principle, by incorporating multiple NIREM dies tuned to emit at different frequencies, multiple vibrational modes could be sequentially detected, making the approach amenable to identification and quantification of complicated molecules within a single NDIR configuration.