毛细石英管构成的高灵敏度光纤气压传感器

为实现高精度的气压测量,提出一种利用飞秒激 光微加工技术与光纤熔接技术制作的法布里- 珀罗(FP)干涉仪(FPI)型光纤气压传感器。利用波长800nm的飞秒 激光脉冲在毛细石英管侧壁上加工一微孔, 利用光纤熔接技术把毛细石英管熔接在一段单模光纤(SMF)和一段多模光纤(MMF)之间,制备 出一种光纤气压传 感器。通过改变传感器的FP腔内气压大小,导致FP腔内气体折射率改变,从而引起传感器 的透射 谱线性漂移,通过计算气压变化量与透射谱的谐振峰波长漂移量之间的关系就能够实现传感 器的气 压测量。理论分析了传感器实现气压测量的机理,实验测量了传感器的灵敏度。实验结 果表明, 传感器对周围气压变化的响应较大,透射谱的谐振峰波长随气压线性变化的灵敏度达到4.22nm/Mpa,而传感器对环境温度变化的响应很小,减少了温度对气压 测量的交叉感染。     

Theoretical study on twisted intramolecular charge transfer of 1-aminoanthraquinone in different solvents

The twisted intramolecular charge transfer and the excited state relaxation of 1-aminoanthraquinone(1-NH_2-AQ)in different solvents are investigated using quantum chemical calculations in this paper.The geometries of the ground state are optimized both in gas and solvents based on the high-level ab initio calculations,the lowest excited singlet state geometry is optimized only in gas for simplicity.An intramolecular charge transfer property is substantiated by the large change of dipole moments between the S_0 and S_1 states.The mechanism of twisted intramolecular charge transfer is proposed by the conformational relaxation on the potential surface of the S_1state.Quantum chemical calculations present that internal conversion and intersystem crossing are important approaches to the ultrafast deactivation of the S_1 state via the twisting of the amino group.The smaller energy difference between the S_0 and S_1 state shows that the internal conversion process is much faster in a polar solvent than in a nonpolar solvent.Energy intersections between the T_2 and S_1 state in cyclohexane and dioxane indicate a faster intersystem crossing process in them than in ethanol.These theoretical results agree well with the previous experimental results.Energy barriers are predicted on the potential surface of the S_1 state,and they have a positive correlation to solvent viscosity,and the timescale of twisted intra-molecular charge transfer in dioxane is predicted to be longer than in cyclohexane and ethanol.     

基于多芯光纤错位熔接结构的温度与折射率同时测量传感器

提出了一款由输入单模光纤(SMF)-多芯光纤(MCF) -多模光纤(MMF)-输出SMF错位熔接构成的光纤Mach-Zehnder 干涉仪(MZI)结构,实现了环境温度和折射率的同时测量。实验结果表明,随着环境温度的 变化,传感器透射谱峰值波长线性漂移,灵敏度达 到54.238pm/℃,而透射谱峰值强度随温度变化不敏感;随着环境折 射率的变化,传感器透射谱峰值 强度线性变化,灵敏度达到10.704dB/RIU(RIU为折射率单位),而透 射谱峰值波长随环境折射率变 化不敏感。通过同时监测传感器输出光谱的峰值波长漂移量和峰值强度变化量,能够实现温 度与折 射率的同时测量。在温度与折射率测量时分别利用波长调制法与强度调制法,因此它们同时 测量不 存在交叉感染。本文传感器具有结构简单、制作容易和灵敏度高等优点,在生物、化学和医 学等领域有广泛的应用前景。