Author Affiliations
Abstract
1 Chinese Academy of Sciences, GBA branch of Aerospace Information Research Institute, Guangzhou, China
2 University of Chinese Academy of Sciences, Beijing, China
A 60-mW solid-state deep ultraviolet (DUV) laser at 193 nm with narrow linewidth is obtained with two stages of sum frequency generation in LBO crystals. The pump lasers, at 258 and 1553 nm, are derived from a homemade Yb-hybrid laser employing fourth-harmonic generation and Er-doped fiber laser, respectively. The Yb-hybrid laser, finally, is power scaling by a 2 mm × 2 mm × 30 mm Yb:YAG bulk crystal. Accompanied by the generated 220-mW DUV laser at 221 nm, the 193-nm laser delivers an average power of 60 mW with a pulse duration of 4.6 ns, a repetition rate of 6 kHz, and a linewidth of ∼640 MHz. To the best of our knowledge, this is the highest power of 193- and 221-nm laser generated by an LBO crystal ever reported as well as the narrowest linewidth of 193-nm laser by it. Remarkably, the conversion efficiency reaches 27% for 221 to 193 nm and 3% for 258 to 193 nm, which are the highest efficiency values reported to date. We demonstrate the huge potential of LBO crystals for producing hundreds of milliwatt or even watt level 193-nm laser, which also paves a brand-new way to generate other DUV laser wavelengths.
193 nm solid-state laser deep ultraviolet LBO crystal sum frequency mixing narrow linewidth Advanced Photonics Nexus
2024, 3(2): 026012
1 长春理工大学 物理学院, 吉林 长春 130022
2 长春理工大学 光电工程学院, 吉林 长春 130022
针对阵列相机的定标检测需求, 研制一套多光源阵列相机辐射定标装置, 通过对积分球衰减效率的理论计算和系统光能量衰减曲线的实际测试, 可得到系统的光学传递曲线, 加上宽量程测量装置实现对系统的光强变化实时测量, 并运用多种光源结合衰减片轮组, 达到宽动态范围为1.728×10-5～54Lux的测试光源连续输出, 分别满足微光阵列相机、强光阵列相机和其他多种阵列相机的多参数检测需求。开展了阵列相机多参数检测实验和标定分析, 实验结果表明: 装置能长久实现光照度特性实时监测和对多种阵列相机进行相机品质检测, 能为阵列相机的运行环境和使用范畴进行判定。
辐射定标 阵列相机 动态范围 信噪比 光响应非均匀性 radiometric calibration array camera dynamic range signal-to-noise ratio non-uniformity of light response
南京理工大学 软化学与功能材料教育部重点实验室, 南京 210094
电化学氧还原反应(ORR)在能源、催化等领域具有广阔的应用前景, 因此开发性能优异、选择性高的催化剂对于促进ORR发展具有重要意义。ORR反应按照反应过程可以分为二电子反应过程和四电子反应过程。本研究以化学修饰石墨烯为原料, 通过调控其表面缺陷并与银-对苯二琨二甲烷(Ag-TCNQ)纳米点复合, 合成了不同缺陷程度的复合催化剂, 在此基础上比较了Ag-TCNQ/高缺陷石墨烯和Ag-TCNQ/低缺陷石墨烯的ORR性能。研究结果显示Ag-TCNQ/高缺陷石墨烯催化ORR的电子转移数为2.4, 双氧水产率达0.62 mg/h, 法拉第效率为64.45%。相比之下, Ag-TCNQ/低缺陷石墨烯参与ORR的电子转移数为3.7, 氧还原半波电位约为0.7 V(vs. RHE)。因此, 高缺陷催化剂促进ORR的二电子过程, 而低缺陷的催化剂促进ORR的四电子过程。在复合材料中, Ag-TCNQ纳米颗粒和石墨烯发挥了各自的结构优势, 形成复合效应, 共同提高了催化活性。
石墨烯 缺陷调控 银-7,7,8,8-四氰基苯醌二甲烷 氧还原反应 graphene defect engineering Ag-7,7,8,8-tetracyanoquinodimethane oxygen reduction reaction
1 昆明理工大学信息工程与自动化学院, 云南 昆明 650500
2 珠海格力电器股份有限公司, 广东 珠海 519000
针对卷积稀疏编码能够较好地保留图像信息特征的这一特点,提出基于低秩分解和卷积稀疏编码的多源图像融合方法。为了避免图像分块处理对图像结构的影响,将每幅待融合图像进行全局处理。首先,通过低秩分解将图像分解成低秩和稀疏两部分;接着,对稀疏部分进行卷积分解,可以训练得到一组稀疏滤波器字典,再将卷积稀疏编码应用到图像的融合中;然后,对低秩和稀疏成分分别设计不同的融合规则,得到融合低秩成分和融合稀疏成分,最终得到融合图像。最后,为了验证所提方法的融合效果,将所提方法与其他方法进行对比实验。实验结果表明,所提方法在视觉效果和客观评价指标方面均取得良好的效果。
图像处理 图像融合 低秩分解 稀疏表示 卷积稀疏编码 激光与光电子学进展
2021, 58(22): 2210009
Author Affiliations
Abstract
1 International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen 518060, China
2 Engineering Technology Research Center for 2D Material Information Function Devices and Systems of Guangdong Province, Shenzhen University, Shenzhen 518060, China
3 College of Electrical and Electronic Engineering, Wenzhou University, Wenzhou 325035, China
A power-scaled laser operation of Pr:YLiF4 (YLF) crystal at 720.9 nm pumped by a 443.6 nm laser diode (LD) module was demonstrated. The 20 W module was used to pump the Pr:YLF crystal, and a maximum output power of 3.03 W with slope efficiency of 30.04% was obtained. In addition, a 5 W blue LD was also used to pump the Pr:YLF laser, and a maximum output power of 0.72 W was obtained at room temperature. The output power was limited by the wavelength mismatch between the single-emitter LD and the absorption peak of the crystal.
rare earth and transition metal solid-state lasers visible lasers diode-pumped lasers Chinese Optics Letters
2020, 18(1): 011405
