Author Affiliations
Abstract
1 State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
2 College of Electronics, Communication, and Physics, Shandong University of Science and Technology, Qingdao 266590, China
3 e-mail: jlhe@sdu.edu.cn
Rhenium disulfide (ReS2), a member of group VII transition metal dichalcogenides (TMDs), has attracted increasing attention because of its unique distorted 1T structure and electronic and optical properties, which are much different from those of group VI TMDs (MoS2, WS2, MoSe2, WSe2, etc.). It has been proved that bulk ReS2 behaves as a stack of electronically and vibrationally decoupled monolayers, which offers remarkable possibilities to prepare a monolayer ReS2 facilely and offers a novel platform to study photonic properties of TMDs. However, due to the large and layer-independent bandgap, the nonlinear optical properties of ReS2 from the visible to mid-infrared spectral range have not yet been investigated. Here, the band structure of ReS2 with the introduction of defects is simulated by the ab initio method, and the results indicate that the bandgap can be reduced from 1.38 to 0.54 eV with the introduction of defects in a suitable range. In the experiment, using a bulk ReS2 with suitable defects as the raw material, a few-layered broadband ReS2 saturable absorber (SA) is prepared by the liquid phase exfoliation method. Using the as-prepared ReS2 SA, passively Q-switched solid-state lasers at wavelengths of 0.64, 1.064, and 1.991 μm are in
Nonlinear optical materials Lasers, Q-switched Lasers, solid-state Mode-locked lasers Nanomaterials Photonics Research
2018, 6(6): 06000498
1 郑州航空工业管理学院信息管理中心，郑州 450046
2 河南工业贸易职业学院信息工程系，郑州 450000
为了解决存在干扰或较大噪声的情况下,利用陀螺信息实现捷联惯导系统（SINS）快速初始对准，首先引入了带高斯噪声等式约束的卡尔曼滤波算法（QECKF），建立了基于QECKF算法的SINS初始对准模型;然后，从车载捷联惯导系统的实际特征出发，提出首先使用IIR低通滤波器降噪，再通过模糊判据结合QECKF算法和卡尔曼滤波（KF）两种滤波方法，该方案实现了陀螺信息的最优化应用以达到快速对准的目的;最后，试验表明在系统受发动机和人员操作的扰动下，该算法相比于常规KF估计将速度提高了近25%，解决了在噪声较大时基于扩展观测量的方法估计发散问题。
捷联惯导系统 初始对准 抗干扰 陀螺信息 等式约束 SINS initial alignment anti-disturbance gyros information equality-constrained
