高数值孔径二次谐波显微术的分子取向探测

基于矢量衍射理论和格林函数法,利用坐标变换分析高数值孔径条件下二次谐波强度随胶原纤维取向的变化规律.研究结果表明,当胶原纤维垂直于z轴时,聚焦光场Ey、Ez分量的增强导致二次谐波相对强度极小值的上升；随着胶原纤维极角的改变,二次谐波强度的整体变化趋势发生变化,同时前向和后向二次谐波之间的强度变化也出现明显差异.     

Analysis of second-harmonic generation microscopy under refractive index mismatch

On the basis of the vector diffraction theory and Green＇s function method, this paper investigates the effects of refractive index mismatch on second-harmonic generation （SHG） microscopy. The polarization distribution and SHG intensity are calculated as functions of the sample radius and probe depth. The numerical results show that refractive index mismatch can result in peak intensity degradation, increase secondary lobes and extension of second- harmonic polarization distribution. Because of the attenuation of polarization intensity, the detected SHG intensity significantly decreases with increasing probe depth, which can limit the imaging depth of SHG microscopy inside thick samples. Forward SHG intensity decays slowly than backward SHG, due to the combination of extension second-harmonic polarization distribution and strong dependency of forward SHG on sample radius.[第一段]     

用于光谱分类的光谱峰谷沿匹配算法

针对超短脉冲激光与气体相互作用产生的非线性荧光光谱的特点,提出了一种新的光谱去噪、特征提取、特征匹配的有效方法.通过对三种气体不同浓度的荧光光谱进行小波压缩去噪,得到5层664个小波系数,重构后获得除噪效果满意而特征信息保持不变的光谱.对重构后的光谱进行光谱峰/谷沿相似度的分析,构造了三种气体的特征谱.在此基础上,经对三种气体光谱进行特征峰/谷沿的匹配分析,提出一种利用同种物质不同浓度下的光谱总体相似度来构造标准特征谱新方法,通过与标准特征谱的匹配分析得到分类结果.实验结果表明,该算法的分类结果受浓度变化影响小,对低至0.05%浓度条件下的全部27条光谱均获得100%的分类识别结果.