Fourier transform infrared (FTIR) spectroscopy is a widely used characterization technique for studying chemical compositions and light-matter interactions in the infrared range. However, it remains challenging to use conventional FTIR equipment to characterize materials that are environmentally sensitive and/or have rough surfaces due to their dynamic response to external stimuli (e.g., humidity) and light scattering from the sample surface. Here, we describe an approach enabling quantitative infrared spectroscopy measurements of these challenging samples, including transmittance, reflectance, and emissivity. We designed and 3D-printed a miniaturized environmental chamber that can be directly inserted into the sample holder of a conventional integrating sphere to perform total transmission and reflection measurements in controlled environments. Moreover, a calibration method was developed to exclude light scattering from rough surfaces of the sample and the distortion created by infrared windows. To illustrate the potential application of this method, we have performed quantitative infrared measurements, both specular and diffusive, on a sapphire standard reference with a specular surface, as well as a textile sample that has a rough surface and is dynamically responsive to changes in humidity. The calibrated results measured with the equipped chamber match those measured without the IR windows, demonstrating the viability of our environmental chamber and the proposed calibration method. This quantitative infrared spectroscopy measurement technique may help advance fields such as metasurfaces and adaptive textiles, where samples are often rough, dynamically responsive, and/or environmentally sensitive.

中文翻译：

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环境敏感和粗糙材料的定量红外光谱

傅里叶变换红外 (FTIR) 光谱是一种广泛使用的表征技术，用于研究红外范围内的化学成分和光-物质相互作用。然而，由于材料对外部刺激（例如湿度）和样品表面的光散射的动态响应，使用传统的 FTIR 设备来表征环境敏感和/或具有粗糙表面的材料仍然具有挑战性。在这里，我们描述了一种方法，可以对这些具有挑战性的样品进行定量红外光谱测量，包括透射率、反射率和发射率。我们设计并 3D 打印了一个微型环境室，可以直接插入传统积分球的样品架中，以在受控环境中执行全透射和反射测量。此外，还开发了一种校准方法，以排除来自样品粗糙表面的光散射和红外窗口造成的失真。为了说明这种方法的潜在应用，我们对具有镜面反射面的蓝宝石标准参考以及具有粗糙表面且对湿度变化动态响应的纺织品样品进行了镜面反射和漫射的定量红外测量. 使用配备的室测量的校准结果与没有 IR 窗口时测量的结果相匹配，证明了我们的环境室和建议的校准方法的可行性。这种定量红外光谱测量技术可能有助于推动超表面和自适应纺织品等领域的发展，这些领域的样品通常是粗糙的、动态响应的、