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向列相液晶(NLC)的取向变化对外界环境敏感,已被作为生物传感的敏感中介材料。研究了侧边抛磨光纤(SPF)用于NLC取向变化测量的传感特性,探索利用SPF测量液晶取向变化的可行性与适用范围。将液晶折射率的理论公式与SPF传输光功率实验数据结合,得到了经验理论关系。实验中设计用机械旋转法改变SPF抛磨面附近NLC的取向。实验结果表明,NLC的取向变化导致SPF传输光功率的变化。以液晶指向矢方位角为表征的NLC的取向变化从0°增大至90°,SPF传输光功率随之增大28.10dB;在0°~30°范围内,SPF传输光功率与NLC的取向变化具有线性关系,光纤传输光功率对取向角度变化的响应平均约为0.359dB/(°)。研究表明SPF可以用于NLC的取向变化的测量并且获得了适用范围,这为基于液晶取向变化的SPF生物传感器的研究提供了参考。
The orientation change of nematic liquid crystal (NLC) is sensitive to the external environment and has been used as a sensitive intermediary material for biological sensing. The sensing properties of side polished optical fiber (SPF) for measuring the orientation change of NLC were studied and the feasibility and applicability of using SPF to measure the orientation change of liquid crystal were explored. By combining the theoretical formula of liquid crystal refractive index with experimental data of SPF transmission optical power, the empirical theoretical relationship is obtained. In the experiment, the mechanical rotation method was used to change the orientation of NLC near the SPF polishing surface. The experimental results show that the change of orientation of NLC leads to the change of optical power of SPF transmission. The orientation change of NLC, which is characterized by the azimuth of liquid crystal director, increases from 0 ° to 90 °, and the optical power of SPF increases by 28.10dB. In the range of 0 ° ~ 30 °, the optical power of SPF and the orientation of NLC The change has a linear relationship, and the response of optical fiber transmission optical power to the variation of orientation angle is about 0.359dB / (°). The results show that the SPF can be used to measure the orientation change of NLC and obtain the applicable range, which provides a reference for the research of SPF biosensor based on the change of liquid crystal orientation.