Abstract This study reports the presence of a nanoscale thin frost layer. During the frosting process, the surface plasmon resonance (SPR) imaging method can be used to overcome conventional optical limits and quantify this layer. The research outlined here also provides quantitative thickness measurement of the thin frost layer via a proposed calibration method based on the measured SPR intensity. The SPR system established in this study consists of a 50 nm gold-coated BK7 cover glass, a prism, a light source, a polarizer, a lens and a filter for the collimated light of a 600 ± 5 nm wavelength, and a CCD camera. The SPR angle of the ice phase is 72°, which corresponds to the ice refractive index of 1.307. The gold-glass specimen is cooled from room temperature (23 ± 1 °C) to −4.0 ± 0.8 °C by using a thermoelectric cooler to maintain the relative humidity of 20 ± 3% (at the room temperature). As a result, it is found that the nanoscale thin frost layer between the frozen condensates exists on the surface. Also, the present study yields the spatial distribution of reflectance that is associated with the frost layer thickness, indicating that the local information about thin frost layer thickness can be obtained through this SPR imaging method. It is found that the SPR imaging method enables successful capture of the depthwise spatial variations of the thin frost layer, showing that the frost layer was grown over time as a result of the de-sublimation of water vapor.

中文翻译：

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使用表面等离子体共振成像定量测量纳米级薄霜层

摘要 这项研究报告了纳米级薄霜层的存在。在结霜过程中，表面等离子体共振 (SPR) 成像方法可用于克服传统的光学限制并量化该层。此处概述的研究还通过基于测量的 SPR 强度的建议校准方法提供薄霜层的定量厚度测量。本研究建立的 SPR 系统由 50 nm 镀金 BK7 盖玻片、棱镜、光源、偏光片、透镜和用于 600±5 nm 波长准直光的滤光片和 CCD 相机组成. 冰相的 SPR 角为 72°，对应冰的折射率为 1.307。金玻璃样品从室温 (23 ± 1 °C) 冷却到 -4.0 ± 0。8 °C 通过使用热电冷却器保持 20 ± 3% 的相对湿度（在室温下）。结果发现，在冻结的冷凝物之间存在纳米级薄霜层。此外，本研究还得出了与霜层厚度相关的反射率空间分布，表明通过这种 SPR 成像方法可以获得有关薄霜层厚度的局部信息。发现 SPR 成像方法能够成功捕获薄霜层的深度空间变化，表明由于水蒸气的升华，霜层随着时间的推移而增长。本研究得出了与霜层厚度相关的反射率空间分布，表明通过这种SPR成像方法可以获得有关薄霜层厚度的局部信息。发现 SPR 成像方法能够成功捕获薄霜层的深度空间变化，表明由于水蒸气的升华，霜层随着时间的推移而增长。本研究得出了与霜层厚度相关的反射率空间分布，表明通过这种SPR成像方法可以获得有关薄霜层厚度的局部信息。发现 SPR 成像方法能够成功捕获薄霜层的深度空间变化，表明由于水蒸气的升华，霜层随着时间的推移而增长。