Author Affiliations
Abstract
1 State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
2 School of Physics Science, University of Jinan, Jinan 250022, China
In this study, an excellent polarization optical crystal with wide transmission range and high laser damage threshold was researched in detail. The laser damage threshold of the crystal was measured to be , which was the highest among polarized optical crystals. The birefringence in the range of 0.435–5 μm was larger than 0.14, while the wedge angle between 31.94° and 32.12° would satisfy the application in this waveband. The extinction ratio of the fabricated prism with the wedge angel of 31.09° was larger than 15,000:1. The results show that the prism is an excellent polarization device, especially in the mid-infrared range and high-power applications.
Glan prism laser damage threshold birefringence polarized optical crystal Chinese Optics Letters
2022, 20(5): 051602
Author Affiliations
Abstract
1 School of Physics and Technology, University of Jinan, Jinan 250022, China
2 e-mail: sps_xiaw@ujn.edu.cn
Graphene-based surface plasmon waveguides (SPWs) show high confinement well beyond the diffraction limit at terahertz frequencies. By combining a graphene SPW and nonlinear material, we propose a novel graphene/AlGaAs SPW structure for terahertz wave difference frequency generation (DFG) under near-infrared pumps. The composite waveguide, which supports single-mode operation at terahertz frequencies and guides two pumps by a high-index-contrast AlGaAs/AlOx structure, can confine terahertz waves tightly and realize good mode field overlap of three waves. The phase-matching condition is satisfied via artificial birefringence in an AlGaAs/AlOx waveguide together with the tunability of graphene, and the phase-matching terahertz wave frequency varies from 4 to 7 THz when the Fermi energy level of graphene changes from 0.848 to 2.456 eV. Based on the coupled-mode theory, we investigate the power-normalized conversion efficiency for the tunable terahertz wave DFG process by using the finite difference method under continuous wave pumps, where the tunable bandwidth can reach 2 THz with considerable conversion efficiency. To exploit the high peak powers of pulses, we also discuss optical pulse evolutions for pulse-pumped terahertz wave DFG processes.
Nonlinear wave mixing Surface plasmons Waveguides Semiconductor materials Photonics Research
2018, 6(3): 03000186
1 武汉大学 测绘学院, 湖北 武汉 430079
2 地球空间信息技术协同创新中心, 湖北 武汉 430079
稀疏数据条件下, 弹道系数是影响低轨空间碎片精确轨道确定与预报的关键因子。使用长期累积的TLE(二行根数)跟踪数据, 通过半长轴的大气阻力摄动方程, 将2 000多个轨道近地点高度低于850 km的空间碎片的弹道系数进行估算, 得到这些空间碎片的弹道系数值, 并给出弹道系数的两个应用实例。第一个应用实例关于利用弹道系数进行TLE的数据质量检测。使用质量检测方法剔除质量可疑的TLE后, 对14个面质比较大的空间碎片进行弹道系数的重新估算, 估算误差均显著减小, 其中11个新计算得到的弹道系数与参考值的相对误差小于20%。第二个实例验证弹道系数在所谓的TLE-OD/OP方法中的应用。以GRACE-B卫星为例, 精密轨道预报为参考, 结果表明利用多组TLE的TLE-OD/OP的轨道预报精度显著优于TLE/SGP4的精度。
空间碎片 轨道确定与预报 弹道系数 低轨卫星 space debris orbit determination and predication ballistic coefficient TLE TLE LEO 红外与激光工程
2016, 45(11): 1129001
1 武汉大学测绘学院，湖北 武汉 430079
2 地球空间信息技术协同创新中心，湖北 武汉 430079
3 国家测绘地理信息局第一地形测量队，陕西 西安 710054
目前空间碎片精密跟踪数据可以通过光学测角和激光测距两种手段获取。文中旨在通过大量的仿真实验来分析上述两种手段获取的数据对碎片定轨及预报性能的影响，以期根据各自的特点更好地利用稀缺的数据资源。首先利用了2015年1月Starlette和Larets卫星CPF精密预报轨道作为参考轨道，仿真生成基于国内区域内4个观测站精度1″的测角数据和精度1 m的测距数据，然后，利用仿真数据生成单站和双站算例并进行定轨，得到完整弧段及部分弧段的测角、测距数据定轨预报结果。结果表明：在上述观测数据精度基础上，测角数据较测距数据在定轨中的表现更加稳定，将完整通过弧段缩短至90 s时，约75%的角度定轨算例的短期(1～2天)预报轨道仍能够满足20″精度要求。实验结果同时表明：单站、双站定轨预报误差分布相似。
角度观测 激光测距 仿真 双站观测 短弧段 angular data laser ranging simulation two stations observation short arc 红外与激光工程
2016, 45(2): 0229004
1 中南大学湘雅二医院骨科, 湖南 长沙 410011
2 湖南中医药大学生物化学与分子生物学教研室, 湖南 长沙 410208
3 湖南中医药大学干细胞调控与应用实验室, 湖南 长沙 410208
肿瘤干细胞(Cancer stem cells, CSCs)是肿瘤组织中一小部分具有自我更新和致瘤性的细胞, 具有特殊的耐药机制, 与肿瘤的复发和治疗失败关系密切。微小RNA(microRNAs, miRNAs)是一类长度约为19~25个核苷酸的内源性非编码单链RNA, 能够通过调控相关靶基因的表达, 参与调控肿瘤干细胞增殖、凋亡、上皮-间质转化等重要的生命过程, 引起CSCs对化疗药物产生原发性多药耐药性。本论文就miRNAs在调控CSCs多药耐药性方面的研究进展作一综述。
肿瘤干细胞 耐药 cancer stem cells microRNA microRNA drug resistance
1 江苏大学理学院， 江苏 镇江 212013
2 江苏大学土木工程与力学学院， 江苏 镇江 212013
基于谱有限元法和模态展开法，针对各向异性薄板，建立激光激发Lamb波的数值模型，得到各向异性薄板中Lamb波沿不同方向传播的色散曲线及Lamb波的传播特性。数值模拟结果表明，谱有限元法能快速有效地计算各向异性板中导波的相速度、群速度，结合模态展开法能够得到任何方向激光激发的Lamb波；Lamb波沿不同方向传播的速度及色散特性与材料的各向异性性质相关。数值模拟为更好地理解复杂介质中导波的传播、指导激励信号的选择及识别检测信号的模态提供了理论依据。
激光技术 Lamb波 谱有限元法 模态展开法 各向异性
Author Affiliations
Abstract
1 State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Ji'nan 250100, China
2 School of Science, Shandong Jianzhu University, Ji'nan 250101, China
3 Institute of Science Technology for National Defence, Shandong University, Ji'nan 250100, China
With a plano-concave cavity, diode-pumped continuous-wave (CW) and actively Q-switched Nd:YVO4 laser operating at 1.34 \mu m is demonstrated. Maximum CW output power of 4.76 W and Q-switched average output power of 2.64 W are obtained with output coupler (transmission T=3.9%). For the Q-switching operation, the theoretically calculated pulse energy and pulse width, with a pulse repetition frequency (PRF) range of 5–40 kHz, coincide with the experimental results. With a T=11.9% output coupler, the maximum peak power of 24.3 kW and minimum pulse width of 6.5 ns are obtained when the PRF is 10 kHz. To the best of our knowledge, this is the shortest actively Q-switched pulse duration ever obtained in a 1.3-\mu m Nd-doped vanadate laser.
Nd:YVO4 主动调Q 理论计算 脉冲宽度 140.3480 Lasers, diode-pumped 140.3530 Lasers, neodymium 140.3540 Lasers, Q-switched 140.3580 Lasers, solid-state Chinese Optics Letters
2011, 9(8): 081401
Author Affiliations
Abstract
1 State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, China
2 Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
3 Key Laboratory of Transparent and Opto-Functional Inorganic Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800, China
4 School of Science, Shandong Jianzhu University, Jinan 250101, China
By aiming the pump wavelength of the laser diode to the absorption peak at 811 nm of the (Nd0:005Lu0:4975Y0:4975)2SiO5 (Nd:LYSO) crystal, an efficient dual-wavelength operation at 1,075 and 1,079 nm is obtained. The maximum output power is 702 mW when the incident pump power is 2.53 W, corresponding to an optical conversion efficiency of 27.7% and a slope efficiency of 37.0%.
Nd:LYSO 双波长 泵浦 效率 140.3480 Lasers, diode-pumped 140.3530 Lasers, neodymium 140.3580 Lasers, solid-state Chinese Optics Letters
2011, 9(7): 071403
1 烟台大学光电信息科学技术学院， 山东 烟台 264005
2 山东大学晶体材料国家重点实验室， 山东 济南 250100
3 山东大学信息科学与工程学院， 山东 济南 250100
报道了一种LD端面抽运Nd:YAG陶瓷，以GaAs作为饱和吸收器件的全固态被动调Q激光器。当抽运功率为23.3 W时，最大平均输出功率为2.06 W，相应的光光转换效率为8.8%，斜效率为9.9%，最高重复频率、最大单脉冲能量、最短脉冲宽度和最大峰值功率分别为49.5 kHz，41.6 μJ，17 ns和2.44 kW。
激光器 Nd:YAG陶瓷 LD抽运 被动调Q 光学学报
2010, 30(s1): s100311
1 山东大学晶体材料国家重点实验室, 山东 济南 250100
2 山东大学信息科学与工程学院, 山东 济南 250100
以Cr:YAG兼作可饱和吸收体和耦合输出镜，实现了激光二极管(LD)端面抽运Nd:LuVO4晶体的微片式被动调Q激光。当抽运功率为13.86 W时，最大平均输出功率为0.508 W，相应的光光转换效率为3.6%，斜率效率为8.3%，最高重复频率、最大单脉冲能量和最短脉冲宽度分别为23.95 kHz，21.21 μJ,4.5 ns，对应的峰值功率为4.71 kW。
激光器 Nd:LuVO4晶体 微片 被动调Q 光学学报
2010, 30(s1): s100509
