掺钐聚合物光纤的光辐射跃迁特性

制备了掺钐螯合物的阶跃型聚合物光纤,研究了螯合物Sm(DBM)3(TOPO)2掺杂的聚甲基丙烯酸甲酯(PMMA)的吸收光谱、激励光谱和发射光谱.根据Judd-Ofelt(J-O)理论,从吸收光谱获得了光学跃迁的强度参数Ω2、Ω4、Ω6分别为18.53×10-20 cm2、2.87×10-20 cm2、3.71×10-20cm2.用光学强度参数计算了激发态4G5/2的辐射跃迁几率(536.19s-1)和辐射寿命(1865μs);同时,计算了4G5/2→6HJ'跃迁的受激发射截面和4G5/2→6FJ'、6HJ'的荧光分支比.分析表明,Sm(DBM)3(TOPO)2掺杂的PMMA可望用于聚合物光纤激光器和放大器.     

组织光学中的Monte Carlo方法

介绍了Monte Carlo方法产生的背景、基本思想及其在组织光学应用中的重要意义，评述了其在组织光学应用中的研究进展，对其发展趋势作了展望。     

Optimizing light delivery in scanning photoacoustic imaging for prostate

The purpose of this study was to optimize the light delivery method in a prostate photoacoustic imaging system. A three dimensional(3D) optical model of the human prostate was developed, and the optical energy distribution in the prostate was estimated via three-dimensional Monte Carlo simulation. Then, the feasibility of prostate photoacoustic imaging(PAI) using two endoscopic light delivery methods was studied. Photoacoustic pressure generation and the corresponding photoacoustic images had been obtained and the comparisons were made between each other. Also, the results of cylinder diffusing light source with different lengths were compared. After that, phantom experiment was carried out to validate the simulation results. Our results would be significant in the optimizing photoacoustic imaging system for an accurate diagnosis of prostate cancer.     

Light absorption distribution of prostate tissue irradiated by diffusing light source

Nitric oxide(NO)and nitric oxide synthase(NOS)have an important role in pain signaling transmission in animal models.Low-level laser therapy(LLLT)is known to have an analgesic effect,but the mechanism is unclear.The aim of the study is to investigate the influence of LLLT on NO release and NOS synthesis in dorsal root ganglion(DRG)neurons,in order to find whether LLLI can ameliorate pain through modulating NO production at the cellular level.The results show that in stress conditions,the laser irradiation at 658 nm can modulate NO production in DRG neurons with soma diameter of about 20μm in a short time after illumination,and affect NOS synthesis in a dose-dependent manner.It is demonstrated that LLLT might treat pain by altering NO release directly and indirectly in DRG neurons.     

图像相关识别器的光信号计算机实时处理

在光学联合变换相关器作图象识别的基础上,将参考图像和目标图像的联合变换功率谱及相关输出强度分布输入计算机进行实时处理,提取并量化谱面上有用的信息,依据相关输出图像相关峰及其锐度对相关程度进行实时量化评价.     

离散介质表面漫反射光的空间分布特性

采用Monte Carlo方法和实验,对离散介质表面漫反射光的空间分布进行了研究.结果表明：离散介质表面并非理想朗伯表面;用置换法对整个生物组织漫反射率的平切光纤测量系统进行简单的定标中,把生物组织表面作为朗伯表面处理将使漫反射率计算结果存在偏差,准确的做法应是对漫反射进行空间积分.     

双层组织模型中漫反射光与内层光学参数关系

研究了双层组织光学参数变化对组织表面漫反射情况的影响规律.采用一个简化的生物组织双层模型,利用Monte Carlo方法和实验进行了研究.结果表明表面漫反射光随内层吸收系数增加而减小,随内层散射系数增加而增强,特别是内层吸收系数或散射系数为小值时,表面漫反射光对内层吸收系数或散射系数的变化非常敏感.     

柱弥散光源内部辐照组织的Monte-Carlo模拟和实验研究

为无损获取组织中光剂量分布信息,本文构建 了弥散光源内部辐照柱状组织的光学模型,利用Monte-Carlo模拟方法实现了 组织内光分布信息的无损预测, 有关模拟结果与实验测量结果基本一致。提出的模型模拟方法对于由弥散光源在组织内部实 施光辐照的临床医用中光剂量的无损确定和治疗方案的优化设计有实际价值。     

Noninvasive photoacoustic measurement of absorption coefficient using internal light irradiation of cylindrical diffusing fiber

Absorption coefficient of biological tissue is an important parameter in biomedicine, but its determination remains a challenge. In this paper, we propose a method using focusing photoacoustic imaging technique and internal light irradiation of cylindrical diffusing fiber (CDF) to quantify the target optical absorption coefficient. Absorption coefficients for ink absorbers are firstly determined through photoacoustic and spectrophotometric measurements at the same excitation, which demonstrates the feasibility of this method. Also, the optical absorption coefficients of ink absorbers with several concentrations are measured. Finally, the two-dimensional scanning photoacoustic image is obtained. Optical absorption coefficient measurement and simultaneous photoacoustic imaging of absorber non-invasively are the typical characteristics of the method. This method can play a significant role for non-invasive determination of blood oxygen saturation, the absorption-based imaging and therapy.