1 中国科学院 长春光学精密机械与物理研究所，吉林长春30033
2 中国科学院大学，北京100049
电渗是当前芯片实验室设备中微流体常用的驱动方式之一，其中电极版图对控制电渗驱动的外电场起到关键作用。针对电渗流电极版图大多基于尺寸优化和形状优化的方法难以大幅提升微流控器件性能的问题，建立电渗流电极拓扑优化模型，采用滤波方程和阈值投影控制电极结构的特征尺寸，通过连续伴随分析方法获得模型的伴随敏度，进而演化电极版图的结构设计变量，最终实现电渗流电极的拓扑优化。基于上述拓扑优化方法设计电渗流微混合器的电极版图，并对影响微混合器混合效果的因素进行分析。结果表明，电渗流微混合器的混合评价指数达到0.047，能够实现两种不同浓度溶液的完全混合。微混合器良好的混合性能验证了本文提出电渗流电极拓扑优化方法的有效性。
微流体 拓扑优化 电渗 微混合器 电极 microfludics topology optimization electroosmosis micromixer electrodes 光学 精密工程
2023, 31(17): 2515
1 淮阴工学院化学工程学院, 江苏省凹土资源利用重点实验室, 江苏 淮安 223003
2 中国科学院兰州化学物理研究所, 羰基合成与选择性氧化国家重点实验室, 兰州 730000
为解决具有MFI拓扑结构的沸石类分子筛(TS-1)孔道适用性窄的问题, 以原位晶化法合成核壳型介微孔复合分子筛xMCM-41@TS-1。结果表明: xMCM-41@S-1具有结晶完整的微孔核相和孔道规整的介孔壳层, 可以有效提高反应传质效率、降低扩散阻力, 促使活性钛中心的有效利用, 同时介孔复合结构有利于缩短物质的扩散路径, 使微孔中的积碳前驱体能及时扩散到表面。催化性能结果表明, xMCM-41-41@TS-1在丁二烯环氧化和环己烷氧化反应中的催化活性分别可以达到TS-1的3倍和2倍, 且循环稳定性远高于TS-1。
核壳结构 介微孔复合结构 活性钛中心 丁二烯环氧化 环己烷氧化 active titanium center butadiene epoxidation core-shell structure cyclohexane oxidation micro-mesoporous
西安石油大学 陕西省油气资源光纤探测工程研究中心和陕西省油气井测控技术重点实验室, 陕西 西安710065
设计并制作了一种基于七芯光纤的应变不敏感温度传感器。该传感器将一段七芯光纤与两段单模光纤进行熔接, 通过优化熔接参数在熔接点处形成两个分别充当光路分束器和耦合器的凸锥结构, 构成了马赫-曾德尔干涉仪(MZI)。实验研究了该传感器对温度和应变的响应特性。结果表明, 传感器的光谱对应变不敏感, 但传感器对温度具有良好的线性响应特性, 在40~200 ℃内, 其谐振光谱波长随温度升高线性红移, 对应温度灵敏度达到93.11 pm/℃, 波长漂移线性度达99.4%。
光纤传感器 七芯光纤 温度 应变不敏感 马赫-曾德尔(Mach-Zehnder)传感器 fiber optic sensor seven-core fiber temperature strain insensitivity Mach-Zehnder sensor
西安石油大学 陕西省油气资源光纤探测工程研究中心, 陕西省油气井测控技术重点实验室, 陕西 西安710065
为了解决光纤光栅在低温环境中的应用问题, 该文从光纤布喇格光栅(FBG)的传感理论出发, 通过深入分析了FBG在-60~25 ℃时热光系数和热膨胀系数的变化。采用2根未封装的FBG进行实验验证, 得到了FBG在低温环境下的响应情况。研究结果表明, FBG在低温环境下具有良好的响应和重复性, 这对FBG在低温环境中的应用具有重要指导意义。
光纤布喇格光栅(FBG) 低温 热光系数 热膨胀系数 fiber Bragg grating(FBG) low temperature thermo-optical coefficient thermal expansion coefficient
1 Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado, USA
2 Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China
Frontiers of Optoelectronics
2020, 13(2): 188
1 上海理工大学光电信息与计算机工程学院, 上海 200093
2 华东师范大学精密光谱科学与技术国家重点实验室, 上海 200062
3 济南量子技术研究院, 山东 济南 250101
实验搭建了基于同步脉冲泵浦的非线性差频中红外光源,利用主-从注入式全光调制技术实现了保偏掺饵和掺镱锁模光纤激光器的被动同步输出,结合高非线性光纤光谱展宽和宽带可调谐滤波器,获得了2940~3260 nm宽波段可调谐的中红外皮秒激光,平均功率为580~926 mW,最大泵浦光转换效率为41%。实验发现,小功率的同步诱导脉冲注入可以大幅降低中红外参量产生的泵浦阈值,从而放宽了高效率中红外产生对高功率泵浦光场的要求。
激光光学 可调谐激光 差频产生 红外激光 同步激光 中国激光
2020, 47(11): 1115001
1 上海理工大学光电信息与计算机工程学院, 上海 200093
2 华东师范大学精密光谱科学与技术国家重点实验室, 上海 200062
3 济南量子技术研究院, 山东 济南 250101
实验探究了基于被动全光同步的中红外差频产生技术,采用主-从注入锁定实现了全保偏掺镱和掺铒锁模光纤激光器的同步脉冲输出,并经过级联光纤放大在PPLN晶体中获得了中心波长为3071 nm的中红外皮秒脉冲,最大泵浦光转换效率为68.3%,峰值平均功率达1.36 W。研究发现,所使用的同步脉冲诱导差频技术能够显著降低中红外产生的泵浦阈值。此外,得益于脉冲产生、同步与放大全链路的保偏光纤架构,中红外超快光源表现出良好的长期稳定性,平均功率的相对抖动低至0.2%。
光纤激光器 差频产生 同步激光 中红外激光 光学学报
2020, 40(20): 2036001
Author Affiliations
Abstract
1 School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, and Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, China
2 Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
3 State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084, China
4 Collaborative Innovation Center of Quantum Matter, Beijing, China
With the recent development of the metasurface, generating an optical vortex in optical far or near fields is realized in various ways. However, to generate vortices in both the near and far fields simultaneously is still a challenge, which has great potential in the future compact and versatile photonic system. Here, a bi-channel optical vortex generator in both the near and far fields is proposed and demonstrated within a single metasurface, where the surface plasmon vortex and the far-field optical vortex can be simultaneously generated under circularly polarized light. The ability of generating vortices with arbitrary topological charges is experimentally demonstrated, which agrees well with simulations. This approach provides great freedom to integrate different vortex generators in a single device, and offers new opportunities for integrated optical communications, trapping, and other related fields.
Photonics Research
2020, 8(6): 06000986
Author Affiliations
Abstract
1 School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, and Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, China
2 Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China
3 Department of Materials Science and NanoEngineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
4 Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
Manipulation of light-matter interaction is critical in modern physics, especially in the strong coupling regime, where the generated half-light, half-matter bosonic quasiparticles as polaritons are important for fundamental quantum science and applications of optoelectronics and nonlinear optics. Two-dimensional transition metal dichalcogenides (TMDs) are ideal platforms to investigate the strong coupling because of their huge exciton binding energy and large absorption coefficients. Further studies on strong exciton-plasmon coupling by combining TMDs with metallic nanostructures have generated broad interests in recent years. However, because of the huge plasmon radiative damping, the observation of strong coupling is significantly limited at room temperature. Here, we demonstrate that a large Rabi splitting (~300 meV) can be achieved at ambient conditions in the strong coupling regime by embedding Ag-WS2 heterostructure in an optical microcavity. The generated quasiparticle with part-plasmon, part-exciton and part-light is analyzed with Hopfield coefficients that are calculated by using three-coupled oscillator model. The resulted plasmon-exciton polaritonic hybrid states can efficiently enlarge the obtained Rabi splitting, which paves the way for the practical applications of polaritonic devices based on ultrathin materials.
Rabi splitting strong coupling transition metal dichalcogenides optical microcavity surface plasmons Opto-Electronic Advances
2019, 2(5): 190008
