摘要：An edge emitting laser based on two-dimensional photonic crystal slabs is proposed. The device consists of a square lattice microcavity, which is composed of two structures with the same period but different radius of air-holes, and a waveguide. In the cavity, laser resonance in the inner structure benefits from not only the anomalous dispersion characteristic of the first band-edge at the M point in the first Brillouin-zone but also zero photon states in the outer structure. A line defect waveguide is introduced in the outer structure for extracting photons from the inner cavity. Three-dimensional finite-difference time-domain simulations apparently show the in-plane laser output from the waveguide. The microcavity has an effective mode volume of about 3.2（λ/nslab）^3 for oscillation mode and the quality factor of the device including line defect waveguide is estimated to be as high as 1300.

摘要：We have investigated the distribution of the electric field in p-i-n type and separate absorption and multiplication(SAM) type GaN avalanche photodiodes under different reverse bias *** have also analyzed the influences of the parameters of each layer,including width and concentration,on the distribution of the electric field,especially on the breakdown *** is found that a relatively high concentration of p-GaN(higher than 1×10 18 cm 3) and low carrier concentration of i-GaN(lower than 5×10 16 cm 3) are helpful to restrict the electric field and reduce the breakdown *** a SAM(p-i-n-i-n) structure,a suitable choice should be made for the concentration and thickness of the intermediate n-GaN layer in order to decrease breakdown voltage and prevent the device from degenerating into a p-i-n ***,the optimized material parameters of each layer are proposed.

摘要：We demonstrate a technique of temperature compensation for 1.3μm InAs/GaAs quantum-dot(QD)lasers by facet coating *** key point of the technique is to make sure that the mirror loss of the lasers decreases as the temperature *** realize this, we design a type of facet coating by shifting the central wavelength of the facet coating from 1310nm to 1480nm, whose reflectivity increases as the emission wavelength of the lasers ***, the laser with the new facet coating exhibits a characteristic temperature doubled in size and a more stable slope efficiency in the temperature range from 10℃ to 70℃, compared with the traditional one with a temperature-independent mirror loss.

摘要：A method to calculate the reflectivity of the coated cavity facet was proposed, and the distribution of the optical power near the two coated cavity facets was calculated for GaN-based laser diodes. A new design method for reducing the optical power at the two cavity facets without changing the output power of laser diodes was discussed, which is helpful to optimize the cavity facet coating and raise the threshold current at which catastrophic optical damage occurs.

摘要：An index guiding photonic crystal fiber used in gas sensing applications is presented. The dependency of the confinement loss and relative sensitivity on the fiber parameters and wavelength is numerically investigated by using the full-vectorial finite element method (FEM). The simulations showed that the gas sensing sensitivity increased with an increase in the core diameter and a decrease in the distance between centers of two adjacent holes. Increasing the hole size of two outer cladding rings, this structure simultaneously showed up to 10% improved sensitivity, and the confinement loss reached 6×10−4 times less than that of the prior sensor at the wavelength of 1.5 μm. This proved the ability of this fiber used in gas and chemicals sensing applications.

摘要：在场的作者高分辨率和宽动态范围 photonic 水晶压力传感器的一个新图案。这个传感器与坐飞机包围的硅杆的方形的数组基于二维的 photonic 水晶。传感器由被联合到 photonic 水晶 nanocavity 的 photonic 水晶波导组成。波导被移开一个排 Si 杆设置， nanocavity 被修改一 Si 杆的半径形成。传感器为 1300 nm1400 nm 波长被设计。模拟结果证明 nanocavity 的反响的波长被增加压力线性地转移到更大的波长。设计传感器有在 0.1 GPa 之间的线性行为到应用压力的 10 GPa 和压力敏感的 8 nm/GPa。

摘要：In this paper, we design and characterize a novel small size four-channel biosensor based on the two-dimensional photonic crystal with introducing waveguides and nano-cavities in the hexagonal lattice of air pores in the silicon slab. By removing a group of air pores, waveguides are achieved, and nano-cavities are shaped by modifying the radius of air pores. Highly parallel operation of this biosensor due to the special architecture is the capability of the designed structure. The biomaterials which are suspended in a liquid medium inside nano-cavities cause effective refractive index changes which lead to the resonant wavelength shift in the output terminal. According to results, with increasing the refractive index of nano-cavities, resonant wavelengths shifts to longer values. For biochemical sensing like DNA molecule and protein and for the refractive index detection, this novel designed biosensor can be utilized.

摘要：具有原子层厚度的过渡金属硫族化合物(TMDs)的光电性质深受缺陷数量(DPs)的影响.在本工作中,我们通过多种制备方法得到了具有不同缺陷数量的单层WS,并进一步揭示了他们之间不同的激子-激子相互作用.稳态荧光(PL)实验观察到在低的激发功率下,具有最少缺陷密度的单层展示出了最高的荧光强度,但在高的激发功率下却被具有更多缺陷的单层所追赶并大幅超越.激发功率依赖实验表明这些单层展现出了不相同的荧光饱和行为,其饱和阈值功率差异甚至高达四个数量级.结合原位荧光成像以及时间分辨荧光实验,我们将这些单层中的荧光演化差异归因于不同的缺陷数量.而这些缺陷数量的差异大大地影响着激子扩散行为并随之带来不同的非辐射激子-激子湮灭.通过谷偏振实验,我们再次检验了这些单层的缺陷数量.本工作揭示了不同缺陷过渡金属硫族化合物单层中截然不同的荧光行为和潜在的激子动力学,很大程度上促进了面向实际应用的相关高性能器件的设计.

摘要：万尼尔构型旨在描述万尼尔函数在实空间上的局域位置及其携带的电荷信息,这一物理概念的提出为刻画天然及人工晶体结构中的波函数提供了全新的视角.在二维高阶拓扑绝缘体中,万尼尔构型中的分数化电荷可以作为一种内禀的拓扑不变量来表征湮灭在体连续谱中的角模式.本文报告了一项基于测量谱电荷分布观测声学体系中万尼尔构型的实验研究.作者在构建的声子晶体中测得了表现为分数化谱电荷的拓扑角模式反常,这种模式反常可以作为一种易于观测的实空间拓扑指标对湮灭在体态中的拓扑角模式进行先验判别.在此基础上,通过将不同的万尼尔构型按照多种方式进行组合,将原本湮没在体连续谱中的角模式调制至带隙中.在组合后的声子晶体中,平庸相和非平庸相结构均可以作为包覆层,从而为在带隙中构造和调控拓扑角模式提供了一种新思路.该研究有望应用于设计高品质因子声谐振腔、声通信以及传感增强等领域.

摘要：有机-无机杂化钙钛矿具有优异的光电性能,如大的光吸收系数、高载流子迁移率等,是理想的光电器件用光吸收材料.然而,杂化钙钛矿薄膜光电器件的性能受多方面因素的影响,例如致密程度、晶界等,同时其内部光激发电子-空穴对的复合也会降低器件的光电流和光响应度.本文以化学气相沉积法生长的高质量石墨烯薄膜为模板,通过两步化学气相沉积制备了甲胺铅碘/石墨烯异质结,并以此制备了柔性光探测器.首先,在生长体系中引入碘化铅,在石墨烯表面外延生长得到高质量的碘化铅;之后,引入甲基碘化铵,得到了具有大晶粒尺寸、致密的甲胺铅碘薄膜.进一步,以此复合薄膜为光吸收层,制备了柔性光探测器,其光响应度达到107 A/W.石墨烯的存在会抑制其中电子-空穴对的复合,从而提高器件的光电流.最后,在人类视觉系统的启发下,设计了柔性光电探测器阵列(24×24)图像传感器;其中,复合薄膜充当了视网膜中的视锥细胞.此图像传感器具有形状识别和颜色辨别的能力,在人造视网膜、生物医学成像、遥感和光通信高性能光电器件的构建方面具有应用潜力.