基于胆甾相液晶薄膜的用于混合挥发性有机化合物传感的光纤传感器。

Optical fiber sensor based on a cholesteric liquid crystal film for mixed VOC sensing.

作者信息

Yang Yunhe, Zhou Dong, Liu Xiujuan, Liu Yongjun, Liu Shuangqiang, Miao Peixian, Shi Yanchao, Sun Weimin

出版信息

Opt Express. 2020 Oct 12;28(21):31872-31881. doi: 10.1364/OE.405627.

Abstract

This paper proposes a novel cholesteric liquid crystal (CLC) film-based dual-probe fiber sensor to monitor volatile organic compound (VOC) gas. The sensor consists of a 2×2 multimode fiber coupler, in which the two output fiber ends are covered by two types of CLC films (CLCF) with different pitches. It can be observed that the reflection peak wavelengths of CLCs shift to the red side as the VOC gas concentration increases. The sensitivities of the two CLCFs are 8.435 nm·L/mmol and 14.867 nm·L/mmol to acetone, 14.586 nm·L/mmol and 29.303 nm·L/mmol to ethanol, respectively. In addition, the dependence of the peak wavelength shift of CLCF on the total concentration of the acetone and ethanol mixed gas at different mixing ratios is measured. The linear relationships between the peak shift of CLCFs, the total mixed gas concentration and acetone/ethanol ratio are calculated using the least-squares method. Therefore, this proposed dual-probe fiber optic sensor can distinguish the concentrations of acetone and ethanol in a mixed gas of acetone and ethanol.

摘要

本文提出了一种基于胆甾相液晶（CLC）薄膜的双探头光纤传感器，用于监测挥发性有机化合物（VOC）气体。该传感器由一个2×2多模光纤耦合器组成，其中两个输出光纤末端覆盖有两种不同间距的胆甾相液晶薄膜（CLCF）。可以观察到，随着VOC气体浓度的增加，胆甾相液晶的反射峰值波长向红端移动。两种CLCF对丙酮的灵敏度分别为8.435 nm·L/mmol和14.867 nm·L/mmol，对乙醇的灵敏度分别为14.586 nm·L/mmol和29.303 nm·L/mmol。此外，还测量了CLCF的峰值波长偏移对不同混合比的丙酮和乙醇混合气体总浓度的依赖性。采用最小二乘法计算了CLCF的峰值偏移、混合气体总浓度与丙酮/乙醇比例之间的线性关系。因此，所提出的双探头光纤传感器能够区分丙酮和乙醇混合气体中丙酮和乙醇的浓度。