Author Affiliations
Abstract
1 Shandong Inspur Artificial Intelligence Research Institute Company Limited, Jinan 250013, China
2 MIIT Key Laboratory of Photonics Information Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, China
Active metasurfaces have recently attracted more attention since they can make the light manipulation be versatile and real-time. Metasurfaces-based holography possesses the advantages of high spatial resolution and enormous information capacity for applications in optical displays and encryption. In this work, a tunable polarization multiplexing holographic metasurface controlled by an external magnetic field is proposed. The elaborately designed nanoantennas are arranged on the magneto-optical intermediate layer, which is placed on the metallic reflecting layer. Since the non-diagonal elements of the dielectric tensor of the magneto-optical material become non-zero values once the external magnetic field is applied, the differential absorption for the left and right circularly polarized light can be generated. Meanwhile, the amplitude and phase can be flexibly modulated by changing the sizes of the nanoantennas. Based on this, the dynamic multichannel holographic display of metasurface in the linear and circular polarization channels is realized via magnetic control, and it can provide enhanced security for optical information storage. This work paves the way for the realization of magnetically controllable phase modulation, which is promising in dynamic wavefront control and optical information encryption.
active metasurface magneto-optical effect polarization multiplexing holography dynamic holographic display Chinese Optics Letters
2024, 22(4): 043601
Author Affiliations
Abstract
1 College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha 410073, China
2 School of Information and Communications, National University of Defense Technology, Wuhan 430035, China
3 Nanhu Laser Laboratory, National University of Defense Technology, Changsha 410073, China
4 Hunan Provincial Key Laboratory of High Energy Laser Technology, National University of Defense Technology, Changsha 410073, China
High-power ultrafast laser amplification based on a non-polarization maintaining fiber chirped pulse amplifier is demonstrated. The active polarization control technology based on the root-mean-square propagation (RMS-prop) algorithm is employed to guarantee a linearly polarized output from the system. A maximum output power of 402.3 W at a repetition rate of 80 MHz is realized with a polarization extinction ratio (PER) of > 11.4 dB. In addition, the reliable operation of the system is verified by examining the stability and noise properties of the amplified laser. The M2 factor of the laser beam at the highest output power is measured to be less than 1.15, indicating a diffraction-limited beam quality. Finally, the amplified laser pulse is temporally compressed to 755 fs with a highest average power of 273.8 W. This is the first time, to the best of our knowledge, that the active polarization control technology was introduced into the high-power ultrafast fiber amplifier.
active polarization control root-mean-square propagation algorithm linearly polarized laser chirped pulse amplification femtosecond laser fiber laser Chinese Optics Letters
2024, 22(4): 041403
1 南京信息工程大学天长研究院，安徽 滁州 239300
2 南京信息工程大学电子与信息工程学院，江苏 南京 210044
3 南京信息工程大学江苏省大气环境与装备技术协同创新中心，江苏 南京 210044
利用光纤倏逝波耦合效应，设计了一种基于石墨烯全光纤结构的主动锁模激光器。该石墨烯全光纤锁模器件基于侧面腐蚀的单模光纤，构建了银/聚二甲基硅氧烷（PDMS）/石墨烯的电容型结构，腐蚀的单模光纤置于PDMS和石墨烯之间。实验结果显示，在电容结构两端施加与激光腔的共振频率一致及其整数倍的周期性方波电压信号，并对腔内光进行调制，可实现1558 nm光纤激光器的主动锁模。所设计的主动锁模激光器获得了基本频率及二次谐波的锁模脉冲，重复频率分别为12.2 MHz和24.4 MHz，实现了电控重复频率的脉冲输出。这种石墨烯全光纤锁模器件具有低成本、低功耗的优势，为实现灵活可控的主动锁模激光器提供了新思路。
激光器 光纤激光器 石墨烯 全光纤结构 主动锁模
强激光与粒子束
2024, 36(1): 013005
1 北京空间机电研究所，北京 100094
2 中国空间技术研究院 空间激光信息感知技术核心专业实验室，北京 100094
3 华中科技大学 电子信息与通信学院，湖北 武汉 430074
4 中国科学技术大学 国家同步辐射实验室，安徽 合肥 230026
海洋立体结构信息是未来实现海洋透明与海洋强国的基础，针对海洋剖面探测能力不足的问题，以及星载海洋剖面多要素同源同域一体化探测空白，开展星载海洋剖面多要素探测技术与系统方案研究，提出新型激光主被动复合、能谱复用探测技术体制，面向未来星载应用，完成星载海洋剖面多要素探测载荷系统设计。其中，激光器谱段设计为486、532 nm多波长一体化最佳配比输出，光电接收探测系统选用1 m×5 m超大口径可折叠光栅主镜，经过仿真分析，探测系统可实现大洋水深100 m深度、温度、盐度以及后向散射系数等多要素同源探测能力，同等体积包络条件下，能量收集能力提升5倍。
激光雷达 海洋剖面探测 主被动复合 大口径光栅 lidar ocean profile detection active and passive composite large aperture grating 红外与激光工程
2024, 53(1): 20230466
1 College of Science, Hunan Province Key Laboratory of Materials Surface & Interface Science and Technology, Central South University of Forestry and Technology, Changsha 410004, Hunan, China
2 College of Science, Jiujiang University, Jiujiang 332005, Jiangxi, China
The immunity of topological states against backscattering and structural defects provides them with a unique advantage in the exploration and design of high-precision low-loss optical devices. However, the operating bandwidth of the topological states in certain photonic structures is difficult to actively tune and flexibly reconfigure. In this study, we propose a valley topological photonic crystal (TPC) comprising two inverse honeycomb photonic crystals, consisting of hexagonal silicon and Ge2Sb2Te5 (GST) rods. When GST transitions from the amorphous phase to the crystalline phase, the edge band of the TPC appears as a significant redshift and is inversed from a"∪"to an"∩"shape with topological phase transition, which enables active tuning of the operating bandwidth and propagation direction of topological edge states. Both the topological edge and corner states in a triangular structure constructed using TPCs can be simultaneously adjusted and reconfigured via GST phase transition, along with a change in the group number of corner states. Using the adjustability of topological edge states and electromagnetic coupling between two different topological bearded interfaces, we develop a multichannel optical router with a high tuning degree of freedom, where channels can be actively reconfigured and their on/off states can be freely switched. Our study provides a strategy for the active regulation of topological states and may be beneficial for the development of reconfigurable topological optical devices.
topological edge states topological corner states phase change material active reconfiguration topological photonic crystal 激光与光电子学进展
2024, 61(5): 0536001
刘琨 1,2,3,*尹慧 1,2,3江俊峰 1,2,3刘铁根 1,2,3赵成伟 1,2,3
1 天津大学精密仪器与光电子工程学院，天津 300072
2 天津大学光电信息技术教育部重点实验室，天津 300072
3 天津大学光纤传感研究所，天津 300072
针对目前深度学习在气体检测领域多聚焦于学习单个任务即气体定性分类或气体体积分数定量回归，忽略了相关任务间的信息关联性，降低了模型学习精度与效率等问题，提出了一种基于一维卷积神经网络和长短期记忆网络的多任务学习模型，即MTL-1DCNN-LSTM，并行实现了混合气体种类定性识别与体积分数定量回归。利用掺铥光纤，搭建了二级放大掺铥环腔光纤激光器，基于有源内腔吸收光谱法探测了CO2和NH3混合气体的吸收光谱数据。将实验数据放入多任务学习模型中训练，并进行超参数优化后，对测试集数据进行测试得到气体识别准确率为100%，NH3体积分数预测决定系数为99.84%，CO2体积分数预测决定系数为99.62%，优于单任务模型与传统的气体反演算法如反向传播神经网络和支持向量机。所提出的深度学习算法与有源内腔法相结合的方法，为吸收光谱型混合气体反演技术的进一步研究提供了新思路。
掺铥光纤激光器 有源内腔法 多任务学习 一维卷积神经网络 长短期记忆网络 激光与光电子学进展
2024, 61(3): 0306002
