作者单位
摘要
1 天津大学精密仪器与光电子工程学院,天津 300072
2 天津市生物医学检测技术与仪器重点实验室,天津 300072
X射线激发发光断层成像(XLCT)是一种新兴的混合成像技术,该技术可同时获得目标体结构信息和功能信息。然而,窄束XLCT重建图像虽然具有高空间分辨率,但X射线利用率较低,数据采集时间过长;锥束XLCT系统提高了X射线利用率,缩短了数据采集时间,但有限的探测角度导致图像重建质量相对较低。为解决上述问题,提高X射线利用率,高效实现多角度高灵敏数据采集,提出了一种基于光子计数测量的锥束XLCT系统,并通过仿体实验对其性能进行了验证。仿体实验结果表明,6个角度锥束照射模式下重建图像的相似度系数(DICE)可达50%,系统保真度(SF)和重建浓度误差(RCE)达到0.7以上,可实现3 mg·mL-1以上的荧光物质质量浓度差距的重建。
医用光学 X射线激发发光断层成像 系统研制 光子计数 仿体实验 
中国激光
2024, 51(3): 0307102
Jianfeng Yue 1,2Yulei Wang 1,2,*Mengyu Jia 1,2Kai Li 1,2[ ... ]Zhiwei Lü 1,2
Author Affiliations
Abstract
1 Center for Advanced Laser Technology, Hebei University of Technology, Tianjin, China
2 Hebei Key Laboratory of Advanced Laser Technology and Equipment, Tianjin, China
This work demonstrates the generation of short pulse duration and high-beam-quality laser pulses using transient stimulated Brillouin scattering at a high repetition rate. Thermal effects and optical breakdown are identified as the main factors that restrict energy reflectivity and beam quality under high repetition rates and transient situations. Through experimental analysis, the interaction length and focal point size are determined to be the key parameters in reducing the thermal effect by reducing the absorption of the laser pulse by the medium. The obtained results show that pulses with a duration of 175 ps and beam quality M2 of around 1.2 can be achieved with a maximum energy reflectivity of over 40% under an interaction length of 50 mm. Furthermore, at an interaction length of 90 mm, a pulse output with a minimum duration of 115 ps (0.5τQ) is achieved.
high beam quality high energy nonlinear optics stimulated Brillouin scattering 
High Power Laser Science and Engineering
2023, 11(6): 06000e70
李凯 1,2宋长禹 3岳剑峰 1,2贾梦瑜 1,2[ ... ]吕志伟 1,2
作者单位
摘要
1 河北工业大学 先进激光技术研究中心,天津 300401
2 河北省先进激光技术与装备重点实验室,天津 300401
3 天津凯普林光电科技有限公司,天津 300300
亚纳秒激光因其对光电器件的损伤优于纳秒激光和飞秒激光,而被广泛应用于光电对抗领域。然而,在常规水冷条件下实现输出数百赫兹焦耳级亚纳秒激光还面临较大的挑战。笔者课题组面向**重大需求,结合端面泵浦微片晶体百皮秒激光产生技术和多程多级板条激光放大技术,对板条激光器的放大性能进行大量的实验研究,并提出了温控双端泵浦技术,弥补双端泵浦结构的缺陷。实现板条激光器单脉冲能量952 mJ,重复频率500 Hz的激光输出,这将为光电对抗系统所需的高重频大能量激光提供优质光源。
板条激光 双端泵浦 高重频 亚纳秒 slab laser dual-end pumping high-repetition rate sub-nanosecond 
红外与激光工程
2023, 52(8): 20230423
作者单位
摘要
1 天津大学精密仪器与光电子工程学院, 天津 300072
2 天津市生物医学检测技术与仪器重点实验室, 天津 300072
扩散拉曼层析成像(DRT)结合了拉曼光谱的分子指纹特性和扩散光学层析成像的深度分辨能力,是一种新型的无标记在体三维光学成像技术。提出一种基于蒙特卡罗光子输运模型的DRT可行性研究方法,该方法应用互易原理建立了快速有效的拉曼数据模拟器,可对实验条件下不同信噪比的拉曼测量数据进行客观模拟,同时结合扩散荧光层析线性成像原理,实现多波段下薄层组织的拉曼光谱分析。通过开展178个波段下5种物质成分的薄层组织模型的模拟重建研究,表明线性DRT图像重建方法能有效构建多种成分浓度的三维空间分布。
医用光学 扩散拉曼层析成像 蒙特卡罗模型 格林互易定理 拉曼光谱分析 代数重建算法 
中国激光
2018, 45(2): 0207025
Author Affiliations
Abstract
1 College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
2 Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin 300072, China
The accuracy of the background optical properties has a considerable effect on the quality of reconstructed images in near-infrared functional brain imaging based on continuous wave diffuse optical tomography (CW-DOT). We propose a region stepwise reconstruction method in CW-DOT scheme for reconstructing the background absorption and reduced scattering coefficients of the two-layered slab sample with the known geometric information. According to the relation between the thickness of the top layer and source–detector separation, the conventional measurement data are divided into two groups and are employed to recon-struct the top and bottom background optical properties, respectively. The numerical simulation results demonstrate that the proposed method can reconstruct the background optical properties of two-layered slab sample effectively. The region-of-interest reconstruction results are better than those of the conventional simultaneous reconstruction method.
170.3880 Medical and biological imaging 170.6960 Tomography 170.5280 Photon migration 170.3660 Light propagation in tissues 170.3010 Image reconstruction techniques 
Chinese Optics Letters
2014, 12(11): 111702
Author Affiliations
Abstract
Laminar optical tomography (LOT) is a new mesoscopic functional optical imaging technique. Currently, the forward problem of LOT image reconstruction is generally solved on the basis of Monte-Carlo (MC) methods. However, considering the nonlinear nature of the image reconstruction in LOT with the increasing number of source positions, methods based on MC take too much computation time. This letter develops a fast image reconstruction algorithm based on perturbation MC (pMC) for reconstructing the absorption or scattering image of a slab medium, which is suitable for LOT or other functional optical tomography system with narrow source-detector separation and dense sampling. To calculate the pMC parameters, i.e., the path length passed by a photon and the collision numbers experienced in each voxel with only one baseline MC simulation, we propose a scheme named as the trajectory translation and target voxel regression (TT&TVR) based on the reciprocity principle. To further speed up the image reconstruction procedure, the weighted average of the pMC parameters for all survival photons is adopted and the region of interest (ROI) is extracted from the raw data to save as the prior information of the image reconstruction. The method is applied to the absorption reconstruction of the layered inhomogeneous media. Results demonstrate that the reconstructing time is less than 20 s with the X-Y section of the sample subdivided into 50 \times 50 voxels, and the target size quantitativeness ratio can be obtained in a satisfying accuracy in the source-detector separations of 0.4 and 1.25 mm, respectively.
170.3880 Medical and biological imaging 170.6960 Tomography 170.5280 Photon migration 170.3660 Light propagation in tissues 170.3010 Image reconstruction techniques 
Chinese Optics Letters
2014, 12(3): 031702

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