基于导模共振微结构的高灵敏度气压/温度双参数光纤传感器

Recently, novel nano-photonic theory and technology have provided a new way to develop atmospheric parameters detecting and sensing system with high sensitivity. However, methods to solve cross-sensitivity between multiple parameters, and the mechanism to realize the enhanced sensitivity have not been fully investigated. The overall aim of the proposed research is to develop novel optical atmospheric pressure and temperature sensing method with high performance through the fabrication of waveguide-grating structures on the end facets of optical fibers. Based on the dynamic characteristics of the guide mode resonance (GMR) effect, Maxwell equations will be exactly solved to describe the process of the propagation, decay and resonance of optical waves (OWs) on the interface of the hybrid nanostructures. Furthermore, the influence of incident angle and wavelength of incident light, thickness of waveguide film and the parameters of gratings on the resonant reflection spectrum will be analyzed to explain the potential mechanism of the enhanced sensitivity and the dual-wavelength method used to solve cross-sensitive problem in proposed fiber sensor. The designed sensor chip will be fabricated by compressed air blowing-coating and laser interference lithography method, and will be characterized through the techniques of near-field characterization and extinction spectrum measurement. The experimental optical path to evaluate the performance of this pressure and temperature dual parameters sensor will be set up, and the relationship between resonant wavelength and the applied pressure/temperature will be studied, which is expected to achieve high wavelength sensitivity (1 nm/hPa) and temperature sensitivity (1.5 nm/°C). Through the introduction of novel nano-photonic technology into atmospheric detection, not only the new effective approaches for meteorological sensing can be brought about, but also the application area of nanotechnology will be widely broadened.

纳米光子技术为发展高灵敏度的气象参数传感与探测方法提供了新途径，但在如何克服多参数间的交叉敏感及传感灵敏度增强方面的机制尚未明确。本课题将光栅共振微结构制备在光纤端面上，发展一种气压/温度双参数传感方法。理论上以复合结构中导模共振(GMR)模式的动态调谐特性为出发点，通过矢量法严格求解麦克斯韦(Maxwell)方程，描绘电磁波的传播、衰减及共振过程，考察系统的光谱响应，阐明双峰共振方法与GMR技术用于提高光纤气象参数传感器灵敏度且实现气压/温度同时测量的物理机理。实验方面，利用压缩空气吹涂、激光干涉光刻方法制备双参数敏感芯片，结合近场表征与消光光谱测试，搭建宽光谱光源光纤传感系统，研究谐振波长随外界气压与温度变化的规律，预计将灵敏度分别提高到1 nm/hPa及1.5 nm/°C以上。将新兴纳米光子技术应用于大气探测，不仅会为气象传感技术的进步带来新的动力，还可以大大拓展纳米技术的应用领域。

基于光子技术的气象参数传感器不仅具有较高的灵敏度，而且由其构筑的传感系统结构简单、功率低。结合光纤传感技术，纳米光子技术将会在气象与环境参数探测中发挥越来越重要的作用，为常规工农业生产和人们日常生活的智能化做出积极贡献。但在如何克服多参数间的交叉敏感及传感灵敏度增强方面的机制尚未明确。本课题将光学共振微结构同光纤基材结合，发展一种气压/温度双参数传感方法。基于全内反射法实现了将单层石墨烯的2.3%吸收提高到100%，以及多通道增强吸收，并从波导模式以及色散关系角度解释了该问题的物理机制。理论上以复合结构中共振模式的动态调谐特性为出发点，通过矢量法严格求解麦克斯韦(Maxwell)方程，描绘电磁波的传播、衰减及共振过程，考察系统的光谱响应，阐明光子共振技术用于提高光纤气象参数传感器灵敏度且实现气压/温度同时测量的物理机理。提出了一种石墨烯-微纳光纤光栅的混合波导结构用于气体传感，包裹微纳光纤光栅的单层石墨烯，使沿微纳光纤光栅表面传输的倏逝场得到大幅增强；同时吸附在石墨烯表面的气体分子，就能改变石墨烯的载流子浓度进而改变其光学折射率，复合波导的有效折射率也将被改变，从而引起相应的波长漂移和衰减，通过检测输出光信号的变化完成气体浓度和光谱之间的映射，可以实现对外界微量分子的浓度传感。实验方面，利用3D双光子光刻技术制备双参数敏感芯片，结合近场表征与消光光谱测试，搭建了宽光谱光源光纤传感系统。该传感系统由宽带白光光源、光纤扇出、光纤端面耦合的微纳结构、气室、光谱仪、以及用于记录光谱数据的电脑组成。研究谐振波长随外界气压与温度变化的规律。将新兴纳米光子技术应用于大气探测，不仅会为气象传感技术的进步带来新的动力，还可以大大拓展纳米技术的应用领域。