文章通过数值模拟系统地研究了单个金纳米长方体颗粒和金纳米长方体阵列的折射率传感性能。结果表明, 四极共振的半峰全宽远小于偶极共振的半峰全宽。当纳米颗粒的边界变得尖锐时, 四极共振的共振波长会发生“红移”, 其折射率灵敏度和品质因子也会显著增加。金纳米长方体阵列的四极共振折射率传感性能(S≈787.72 nm /RIU, FOM≈13.82)优于单个颗粒的传感性能。等离子体四极共振在金纳米长方体阵列中的高灵敏度、大FOM和优异的稳定性使其在生物传感器领域具有潜在的应用前景。

设计了一种简洁的角度扫描棱镜SPR传感系统, 反射式平行光路设计简化了系统结构。 其主要包括光源及光强感知、 平行光路结构、 电机与温度控制模块构成。 通过单电机扫描入射角与温度控制, 实现了对葡萄糖的折射率浓度特性有效测量。 理论分析存在交叉灵敏度矩阵可同时度量温度及葡萄糖质量浓度共振角度的变化规律, 且实验得其灵敏矩阵。 为区分温度和质量浓度对共振角度的影响以及校正SPR温度漂移提供参考。

本文报道了一种基于色相算法的彩色表面等离子体共振(SPR)成像传感器, 该传感器不仅能够对发生于SPR芯片表面的物理化学反应进行直观的图像观测, 还能基于色相算法对这些表面反应进行定量分析。利用自制的波长/图像同步检测型SPR传感器, 实验获得了不同共振波长对应的共振图像, 然后借助色相算法求得每一幅共振图像对应的二维色相分布及其平均色相, 建立了共振波长与图像平均色相的依赖关系, 用于优化基于色相参数的SPR折射率灵敏度。实验选择起始共振波长为650 nm, 测得基于色相的折射率灵敏度为3 338/RIU, 是基于共振波长的折射率灵敏度的1.49倍。利用彩色SPR成像技术能够直观地观测到金膜表面涂布的聚四氟乙烯薄膜的不均匀性, 再通过计算图像局部区间的平均色相, 可以定量获得不同薄膜厚度对应的折射率灵敏度。实验结果证明了基于色相算法的彩色SPR成像传感器明显优于常规SPR传感器。

采用水提取分级醇沉制得宣木瓜多糖,利用苯酚-硫酸法测定多糖含量,采用高效尺寸排阻色谱-多角度激光光散射-示差折光联用技术(HPSEC-MALLS-RI)分析多糖分子量和分子量分布,用多糖体外刺激巨噬细胞,Griess法检测NO释放量.系列研究旨在考察宣木瓜多糖含量、分子量和分子量分布以及免疫活性,为宣木瓜多糖研究积累实验资料和科学依据;并为中药多糖研究提供较为简单、系统的方法与思路.结果表明,不同乙醇浓度(φ)沉淀宣木瓜多糖含量的高低顺序是:95%＞80%＞40%≥60%＞20%,95%乙醇可较完全地沉淀多糖;当乙醇浓度从20%上升到95%时,粗多糖纯度由35.1%上升至45.0%.宣木瓜多糖主要有3个色谱峰,不同浓度醇沉的多糖经HPSCE分离后出峰位置和数量没有明显差别,表明它们含有的多糖种类相似;重均分子量(Mw)分别为6.570×104 g·moL－1和1.393×104 g·moL－1以及小于1万未能获得准确值;前两种多糖的分子量分布指数(Mw/Mn)分别是1.336和1.639;本试验中宣木瓜多糖对巨噬细胞Raw264.7产生NO没有明显的促进作用。

The long period fiber grating (LPFG) is widely used as a sensor due to its high sensitivity and resolution. However, the broad bandwidth of the attenuation bands formed by the mode coupling between the fundamental core mode and the cladding modes constitutes a difficulty when the device is used as a conventional sensor. To overcome this limitation, a Michelson interferometer-type sensor configuration has been developed, using an LPFG grating pair formed by coating a mirror at the distal end of the LPFG. This sensor configuration is more convenient to use and is able to overcome the limitations of the single LPFG based sensor as the shifts in the attenuation bands being more easily detectable due to the formation of the sharp spectral fringe pattern in the LPFG based Michelson interferometer. In this work, I studied the LPFG based Michelson interferometer as the refractive index sensor and discussed the sensitivity enhancement of the LPFG based Michelson interferometer as a refractive index sensor by employing higher order cladding modes and by reducing the cladding radius. The results demonstrated the HE17 mode with a cladding radius of 62.5 μm, in the range of surrounding refractive index (SRI) of 1 – 1.45, and its resonant peak showed a wavelength shift of 26.99 nm/RIU. When the cladding region was further reduced to 24 μm, the resonant peak showed a wavelength shift of 569.88 nm/RIU, resulting in a sensitivity enhancement of nearly 21 times. However, as the cladding region was etched further, then the HE17 order cladding mode and higher mode would be cut off. Therefore, the implementation of high sensitivity for SRI sensing with the reduced cladding in the LPFG based Michelson interferometer is dependent on the proper combination of the cladding radius and cladding mode order.

We proposed a new bilayer surface plasmon resonance-based fiber-optic refractive index sensor with silver and an over-layer of TiO2. We numerically investigated the optimal thickness of TiO2 over-layer in the proposed sensor and compared its performance to that based on typical bimetallic layers of silver-and-gold in the aqueous media using finite-difference time domain approach. We show that the use of TiO2 over-layer greatly improves the sensor performance in terms of sensitivity and signal-to-noise ratio compared to that with gold as the over-layer. Not only does the TiO2 over-layer offer a cost-effective alternative to gold for overcoming the oxidation problem, but also it allows resonance wavelength-tunability.

通过模式耦合理论, 建立了基于长周期光纤光栅(LPFG)的二层圆光波导模型; 结合传输矩阵法, 仿真得到了外部介质折射率呈线性分布情况下LPFG的透射谱。仿真结果表明: 该结构下的LPFG透射谱特性强烈依赖于外部介质折射率梯度, 当外部介质折射率梯度升高, 透射谱的损耗峰深度逐渐降低, 损耗峰3dB带宽逐渐增加, 且增加量与折射率梯度的增加量呈较好的线性关系; 当外部折射率梯度由1.111 1×10-7 riu/mm增加到1.111 1×10-5 riu/mm时, 其梯度灵敏度可达到2.2×107 nm·mm/riu。这一结果使折射率梯度的高灵敏度测量成为可能, 为设计和制作基于LPFG的折射率梯度传感器提供了一定的理论依据,并有望用于生化反应中微小尺度下折射率呈梯度分布的液相介质的测量。

研究结构化光纤Bragg光栅（FBG）在折射率（RI）呈线性分布的液相介质环境下的响应特性。数值仿真结果表明，结构化FBG的反射谱特性强烈依赖于液相介质折射率（RI）的线性分布函数的某些特征参数，比如液相介质的RI沿FBG轴向的分布梯度、RI在FBG两端的差值等。基于理论仿真结果，建立了结构化FBG在低RI区（1.330~1.360）对液相介质的RI梯度进行测量的线性近似理论模型。通过相关实验研究，证明了理论仿真和分析的合理性及基于结构化FBG的RI梯度传感器在现实应用中的可行性。