Soliton fusion and fission for the high-order coupled nonlinear Schr?dinger system in fiber lasers

With the rapid development of communication technology,optical fiber communication has become a key research area in communications.When there are two signals in the optical fiber,the transmission of them can be abstracted as a high-order coupled nonlinear Schr¨odinger system.In this paper,by using the Hirota’s method,we construct the bilinear forms,and study the analytical solution of three solitons in the case of focusing interactions.In addition,by adjusting different wave numbers for phase control,we further discuss the influence of wave numbers on soliton transmissions.It is verified that wave numbers k₁₁,k₂₁,k₃₁,k₂₂,and k₃₂can control the fusion and fission of solitons.The results are beneficial to the study of all-optical switches and fiber lasers in nonlinear optics.     

求一个特殊矩阵的n次幂的方法

由两个特殊的低阶方阵的n次幂,猜测出一种特殊形式的k阶方阵A的n次幂,然后通过数学归纳法证明了结果的正确性.本文提供了一种求特殊幂的方法.对求矩阵的幂给出了一种新思路.     

宽束冷阴极和部端霍尔离子源对薄膜透过率和应力影响的比较

在宽束冷阴极离子源和端部霍尔离子源辅助沉积情况下，利用南光ZZS700 1/G箱式镀膜机，通过实验分别验证了这两种离子束辅助沉积对光学膜层透过率和应力的影响。通过对大量实验数据进行分析，得出利用低能量和大电流离子束辅助沉积光学薄膜时，膜层性能优于高能量离子束辅助沉积膜层。分析了膜层特性改变的原因，并提出了合理的工艺参数。实验结果表明，低能量、大电流的离子束辅助沉积使光学薄膜的性能更佳。     

红莲型杂交稻新不育系珞红4A的选育

在超级稻珞优8号的母本珞红3A的基础上利用杂交和分子标记辅助选择技术,结合田间自然接虫鉴定,聚合了抗褐飞虱基因Bph14和Bph15,成功选育了红莲型水稻新不育系珞红4A.该品种不育性稳定,开花习性好,制种、繁种产量高,配合力强,大田表现为显著的褐飞虱抗性.以珞红4A为母本大规模测配、选育出的包括珞红4A/810323、珞红4A/010436、珞红4A/010492、珞红4A/R5814和珞红4A/9311等苗头组合,普遍表现出褐飞虱抗性好的优势.     

High-power MoTe_2-based passively Q-switched erbium-doped fiber laser

Materials in the transition metal dichalcogenide family, including WS_2, MoS_2, WSe_2, and MoSe_2, etc., have captured a substantial amount of attention due to their remarkable nonlinearities and optoelectronic properties.Compared with WS_2 and MoS_2, the monolayered MoTe_2 owns a smaller direct bandgap of 1.1 eV. It is beneficial for the applications in broadband absorption. In this letter, using the magnetron sputtering technique, MoTe_2 is deposited on the surface of the tapered fiber to be assembled into the saturable absorber. We first implement the MoTe_2-based Q-switched fiber laser operating at the wavelength of 1559 nm. The minimum pulse duration and signal-to-noise ratio are 677 ns and 63 dB, respectively. Moreover, the output power of 25 mW is impressive compared with previous work. We believe that MoTe_2 is a promising 2D material for ultrafast photonic devices in the high-power Q-switched fiber lasers.     

法布里-珀罗干涉在超短激光脉冲测量中的应用

把大学物理光学中法布里-珀罗干涉的方法应用于超短激光脉冲测量.分析了利用法布里-珀罗标准具中多光束干涉产生自相关信号进行超短激光脉冲测量的原理;进行了实验测试并与迈克耳孙干涉自相关的测量结果进行了对比,实现了对超短激光脉冲时间宽度的测量.     

散射介质中多重散射太赫兹脉冲的时域统计特性

对散射介质中多重散射太赫兹脉冲的时域统计特性进行了分析.给出了时间延迟量取不同值时电场的概率分布、散射场强度及其概率分布、散射场实部和虚部的概率分布.由于脉冲的宽带特性及瞬间特性,多重散射场概率统计分布与不同时间延迟量有关,太赫兹脉冲多重散射场的统计特性分布是非平稳过程.     

Q-switched fiber laser operating at 1.5 μm based on WTe_2

Compared with the extensively studied MoS2 and WS2, WTe_2 owns a smaller bandgap, which is applicable to a near-infrared system in photodetectors, communications, and ultrafast optics. In this work, the WTe_2 saturable absorber(SA) with the tapered fiber structure is prepared by the magnetron-sputtering technology, which enables the prepared SA to be low in cost and have strong nonlinearity. The modulation depth of the prepared WTe_2 SA is measured as 31.06%. The Q-switched fiber laser operating at 1.5 μm is successfully investigated by incorporating the proposed SA into the prepared ring cavity. To the best of our knowledge, this is the first attempt of WTe_2 in the Q-switched fiber laser at 1.5 μm.     

利用Pd催化合成单晶GaN纳米线的光学特性(英文)

基于金属元素钯具有的催化特性,采用射频磁控溅射方法,在Si(111)衬底上沉积Pd:Ga2O3薄膜,然后在950℃下对薄膜进行氨化,制备出大量GaN纳米线.采用扫描电子显微镜(SEM)、X射线衍射(XRD)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)等技术手段对样品的结构、形貌和成分进行分析.结果表明,制备的样品为具有六方纤锌矿结构的单晶GaN纳米线,直径在20-60nm范围内,长度为几十微米,表面光滑无杂质,结晶质量较高.用光致发光光谱对样品的发光特性进行测试,分别在361.1、388.6和426.3nm处出现三个发光峰,且与GaN体材料相比近带边紫外发光峰发生了较弱的蓝移.对GaN纳米线的生长机制也进行了简单的讨论.     

Fabrication of Mn-Doped GaN Nanobars

We report a new method for large-scale production of GaMnN nanobars, by ammoniating Ga2O3 films doped with Mn under flowing ammonia atmosphere at 1000oC. The Mn-doped GaN sword-like nanobars are a single-crystal hexagonal structure, containing Mn up to 5.43 atom%. Thickness is about 100 nm and with a width of 200-400 nm. The nanobars are characterized by x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and photoluminescence. The GaN nanobars show two emission bands with a well-defined PL peak at 388 nm and 409 nm respectively. The large distinct redshift （409 nm） are comparable to pure GaN（370 nm） at room temperature. The red-shift photoluminescence is due to Mn doping. The growth mechanism of crystalline GaN nanobars is discussed briefly.