1 南京工业大学 数理科学学院， 江苏 南京 211816
2 浙江农林大学 光机电工程学院， 浙江 杭州 311300
随着信息化时代的高速发展，对微电子器件中光电材料的选择、新功能的开发提出了更高的要求。传统光电器件大多利用半导体材料在光照下电导率增加的正光电导性效应进行功能化设计。近年来，研究发现还存在另一种反常的光电导效应——负光电导（Negative photoconductivity，NPC），即在光照条件下电导率降低，由于其在光电探测、逻辑器件、神经形态器件、低功耗非易失性存储器方面的潜在应用而备受关注。NPC的产生机制一般包括载流子的俘获效应、表面分子的吸附-解吸、表面等离子体极化激元和局域表面等离子体共振、光辐射热效应等。本文详细讨论了不同光电器件中NPC产生的物理机制，分析了材料选择、器件结构设计、能带结构变化对不同异质结器件中NPC效应的影响，概括了光电器件中负光电导效应的实际应用，这为光电器件的性能优化和新型光电器件设计提供了重要参考，为未来异质结光电信息器件实现尺寸更小、光导增益更高、速率更快、功耗更低奠定了科学基础。
负光电导 应用 光电器件 negative photoconductivity application optoelectronic devices
中国电子科技集团公司 第三十四研究所，广西 桂林 541004
针对特殊应用领域对高可靠性、轻量化、输出功率大于100 mW、重频大于50 MHz的飞秒激光器的需求，设计了一种Figure-9腔锁模全保偏掺铒光纤飞秒激光器，通过在腔锁模振荡器中引入π/2相移偏置，降低了振荡器的自启动锁模阈值。实验结果表明：当泵浦功率为130 mW时，振荡器可获得平均功率为12 mW、重频为85.89 MHz、脉冲宽度为249 fs的稳定锁模脉冲序列输出；采用一级正色后向泵浦散掺铒增益光纤放大器进行放大后，最终可获得平均功率为113 mW、脉冲宽度为107 fs的飞秒脉冲序列输出。
保偏 Figure-9腔 激光器 锁模 非线性放大光纤环 polarization maintaining, Figure-9 cavity, laser,
中国电子科技集团公司 第二十六研究所，重庆 400060
该文研制了一种高性能温补型薄膜体声波谐振(TC-FBAR)滤波器。采用COMSOL软件对高性能温补型结构的谐振器进行建模和仿真，在常规一维Mason等效电路模型的基础上进行修正，再在ADS中对滤波器进行仿真优化设计，得到阶梯型结构的TC-FBAR滤波器。采用空腔型结构并制备出温补型FBAR滤波器芯片，同时在常规TC-FBAR基础上制备空气桥和凸起层结构，得到双空气桥结构的高性能TC-FBAR滤波器。测试结果表明，滤波器的中心频率为2.43 GHz，最小插损为1.02 dB，1 dB带宽为70.5 MHz，频率温度系数为1.82×10-6/℃。
温补型薄膜体声波谐振器(TC-FBAR) 滤波器 温补层 频率温度系数(TCF) temperature compensation thin-film bulk acoustic r filter temperature compensation layer frequency temperature coefficient(TCF)
Author Affiliations
Abstract
1 Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology, Center for Advanced Material Diagnostic Technology, and College of Engineering Physics, Shenzhen Technology University, Shenzhen 518118, China
2 School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
With different interactions between material and femtosecond lasers, two-dimensional (2D) and three-dimensional (3D) waveguide couplers, whose separation distances are fabricated in z-cut lithium niobate crystal by femtosecond laser writing, are reported. Experimentally and numerically, it is shown from results that the guidance is only propagating along TM polarization due to the Type I modification and holds equal splitting ratios, which are the same as power splitters at 632.8 nm. The propagation losses of 2D and 3D waveguide couplers exhibit better transmission properties than those of the previously reported Type I Y-junction waveguide splitters.
femtosecond laser writing beam splitters lithium niobate Chinese Optics Letters
2023, 21(11): 112201
1 中国科学院合肥物质科学研究院，安徽 合肥 230031
2 中国科学技术大学，安徽 合肥 230026
3 龙岩烟草工业有限责任公司，福建 龙岩 364030
为提高活性炭含量检测的效率与精度，基于微波谐振技术设计了一种活性炭滤棒微波幅值变化信号采集装置，并将高斯滤波和惩罚最小二乘算法相结合对微波幅值变化信号进行降噪和基线扣除处理。首先，比较了不同高斯窗口长度的滤波效果，选用非对称最小二乘法、自适应迭代重加权惩罚最小二乘法、非对称重加权惩罚最小二乘法和多约束重加权惩罚最小二乘法等4种处理方法对微波幅值变化信号进行基线校正，再求出基线校正后微波幅值变化信号的峰高、峰面积与半峰全宽，然后比较了基于支持向量回归机、偏最小二乘算法与反向传播神经网络建立的模型的预测结果。结果显示，活性炭质量的最佳模型为“峰面积-活性炭质量”，模型决定系数为0.9924，平均绝对误差为0.7979 mg，相对标准偏差为1.4962%。活性炭质量重复性检测最大标准差为1.85 mg，活性炭质量检测的最小绝对偏差为0.03 mg，活性炭质量检测最小相对偏差为0.05%。该方法为烟用活性炭滤棒中活性炭的定量分析提供了一种快速有效的方法。
测量 微波谐振技术 基线校正 惩罚最小二乘法 活性炭 质量 激光与光电子学进展
2023, 60(17): 1712007
Author Affiliations
Abstract
1 Zhejiang Lab, Hangzhou 310000, China
2 Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
3 Graduate School of China Academy of Engineering Physics, Beijing 100088, China
Diagnosis of fluids is extremely significant at high temperatures and high pressures. As an advanced imaging technique, high-energy proton radiography has great potential for application to the diagnosis of high-density fluids. In high-energy proton radiography, an angular collimator can control the proton flux and thus enable material diagnosis and reconstruction of density. In this paper, we propose a multi-material diagnostic method using angular collimators. The method is verified by reconstructing the density distribution from the proton flux obtained via theoretical calculations and numerical simulations. We simulate a 20 GeV proton imaging system using the Geant4 software toolkit and obtain the characteristic parameters of single-material objects. We design several concentric spherical objects to verify the method. We discuss its application to detonation tests. The results show that this method can determine the material and boundary information about each component of a multi-material object. Thus, it can be used to diagnose a mixed material and reconstruct densities in a detonation.
Matter and Radiation at Extremes
2023, 8(4): 046902
1 山东大学物理学院晶体材料国家重点实验室，山东 济南 250100
2 南开大学电子信息与光学工程学院微尺度光学信息基础科学重点实验室，天津 300350
3 山东师范大学物理与电子科学学院山东省光场调控工程技术中心，山东省光学与光子器件重点实验室，山东 济南 250358
利用飞秒激光直写技术制备Tm∶YAP光波导并实现1.9 μm波导调Q锁模激光输出。结合具有金属特性的NbSe2薄膜作为可饱和吸收元件进行光学调制，波导激光输出的激光脉冲重复频率为7.8 GHz，最短脉宽为62 ps。这也是已报道的从Tm∶YAP波导中获得的最短激光脉宽。通过调整泵浦光的偏振，可以获得1855.87/1892.54 nm的双波长激光输出。结果表明，具有金属特性的NbSe2薄膜在调制中红外超快脉冲激光器方面具有较大的应用价值。此外，双波长输出的紧凑型Tm∶YAP波导脉冲激光器在多功能集成光子学研究方面具有较好的应用前景。
激光器 飞秒激光直写 波导激光 Tm∶YAP NbSe2 光学学报
2023, 43(16): 1623018
Author Affiliations
Abstract
1 State Key Laboratory for Manufacturing System Engineering and Shaanxi Key Laboratory of Photonics Technology for Information, School of Electronic Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China
2 School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Wettability is one of a solid surface’s fundamental physical and chemical properties, which involves a wide range of applications. Femtosecond laser microfabrication has many advantages compared to traditional laser processing. This technology has been successfully applied to control the wettability of material surfaces. This review systematically summarizes the recent progress of femtosecond laser microfabrication in the preparation of various superwetting surfaces. Inspired by nature, the superwettabilities such as superhydrophilicity, superhydrophobicity, superamphiphobicity, underwater superoleophobicity, underwater superaerophobicity, underwater superaerophilicity, slippery liquid-infused porous surface, underwater superpolymphobicity, and supermetalphobicity are obtained on different substrates by the combination of the femtosecond laser-induced micro/nanostructures and appropriate chemical composition. From the perspective of biomimetic preparation, we mainly focus the methods for constructing various kinds of superwetting surfaces by femtosecond laser and the relationship between different laser-induced superwettabilities. The special wettability of solid materials makes the femtosecond laser-functionalized surfaces have many practical applications. Finally, the significant challenges and prospects of this field (femtosecond laser-induced superwettability) are discussed.
Ultrafast Science
2022, 2(1): 9895418
