Vap Jason C, Nauyoks Stephen E, Benson Michael R, Marciniak Michael A
Department of Electrical and Computer Engineering, Air Force Institute of Technology, Wright-Patterson AFB, Ohio 45433, USA.
Department of Engineering Physics, Air Force Institute of Technology, Wright-Patterson AFB, Ohio 45433, USA.
Rev Sci Instrum. 2017 Oct;88(10):103104. doi: 10.1063/1.4990003.
Nanostructured optical materials, for example, metamaterials, have unique spectral, directional, and polarimetric properties. Samples designed and fabricated for infrared (IR) wavelengths have been characterized using broadband instruments to measure specular polarimetric transmittance or reflectance as in ellipsometry or integrated hemisphere transmittance or reflectance. We have developed a wavelength-tunable IR Mueller-matrix (Mm) polarimetric scatterometer which uses tunable external-cavity quantum-cascade lasers (EC-QCLs) to tune onto and off of the narrowband spectral resonances of nanostructured optical materials and performed full polarimeteric and directional evaluation to more fully characterize their behavior. Using a series of EC-QCLs, the instrument is tunable over 4.37-6.54 μm wavelengths in the mid-wave IR and 7.41-9.71 μm in the long-wave IR and makes measurements both at specular angles, acting as a Mm polarimeter, and at off-specular angles, acting as a Mm scatterometer. Example measurements of an IR thermal metamaterial are shown.
例如，超材料这类纳米结构光学材料具有独特的光谱、方向和偏振特性。针对红外（IR）波长设计和制造的样品已使用宽带仪器进行了表征，以测量镜面偏振透射率或反射率，如椭圆偏振测量法中的那样，或积分半球透射率或反射率。我们开发了一种波长可调谐的红外穆勒矩阵（Mm）偏振散射仪，它使用可调谐外腔量子级联激光器（EC-QCL）调谐到纳米结构光学材料的窄带光谱共振上或从其上调谐下来，并进行了全偏振和方向评估，以更全面地表征其行为。使用一系列的EC-QCL，该仪器在中波红外波段的4.37 - 6.54μm波长范围内以及长波红外波段的7.41 - 9.71μm波长范围内可调谐，并既可以在镜面角度进行测量（作为Mm偏振计），也可以在非镜面角度进行测量（作为Mm散射仪）。展示了红外热超材料的示例测量结果。
