对HgCdTe红外探测器CdSexTe1-x衬底材料的分子束外延生长条件、组分调整等进行了简单介绍。生长条件包括生长结构(主要有CdSexTe1-x/CdTe/ZnTe/Si、CdSexTe1-x/ZnTe/GaAs等)、生长温度(300℃左右)、生长厚度(5 m左右)等。组分调整包括分析Se组分随(JSe+JTe)/JCd和JSe/(JSe+JTe)的变化。JSe/(JSe+JTe)值较小时, Se组分较难融入外延层; JSe/(JSe+JTe)值较大时, Se组分增长较迅速。同时, 若JSe/(JSe+JTe)值较小, 则Se组分增长趋势相对较易控制。当JSe/(JSe+JTe)值一定时, Se组分随着(JSe+JTe)/JCd的减小而增大。Se组分变化的突增点随(JSe+JTe)/JCd值的减小而增大。本文可为高性能HgCdTe红外探测器的制备提供一定的参考。
分子束外延 组分调整 CdSexTe1-x CdSexTe1-x molecular beam epitaxy composition adjustment
对影响Hg1-xCdxTe红外探测器性能的不同调控技术——包括材料调控(组分及温度、掺杂浓度、压强及应力等对材料性能的调控)、器件结构调控(n-on-p、p-on-n、p-i-n、n-B-n等器件结构的调控)和工艺调控(各种工艺调控对材料制备和器件制备等的影响)等——进行了简单介绍，以合理调控器件性能、有效降低器件暗电流、提高器件工作温度等，从而促进Hg1-xCdxTe红外探测器在降低成本、减小功耗、提高可靠性等方面的发展。
红外探测器 调控技术 infrared detector Hg1-xCdxTe Hg1-xCdxTe regulation technology
1 1.南昌航空大学 江西省金属材料微结构调控重点实验室, 南昌 330063
2 2.南昌航空大学 材料科学与工程学院, 南昌 330063
3 3.福州大学 材料科学与工程学院, 福州 350108
高熵氧化物以其独特的结构和潜在的应用前景引起了越来越多的关注。本工作采用简单易行的固相反应法制备了M3O4(M=FeCoCrMnMg)高熵氧化物粉体, 采用不同手段对粉体进行表征, 并采用涂覆法制备了 M3O4/泡沫镍(M3O4/NF)复合电极, 研究其超电容性能。结果表明, 随着煅烧温度升高, Fe2O3(H)/Co3O4(S)/Cr2O3(E)和Mn2O3(B)相继固溶进入尖晶石主晶相晶格; 在900 ℃煅烧2 h所得M3O4粉体的平均粒径为0.69 μm, 具有单一尖晶石结构(面心立方, Fd-3m, a=0.8376 nm), 且Fe、Co、Cr、Mn和Mg五种元素在晶粒内均匀分布, 呈典型的高熵氧化物特征。此外, M3O4/NF复合电极在1 mol/L KOH的电解液中, 当电流密度为1 A·g-1时, 其质量比电容达到193.7 F·g-1, 可见M3O4高熵氧化物在超级电容器电极材料领域具有良好的应用前景。
Author Affiliations
Abstract
1 CREOL, The College of Optics & Photonics, University of Central Florida, Orlando, Florida 32816-2700, USA
2 Bell Laboratories, Alcatel-Lucent, Holmdel, New Jersey 07733, USA
Non-mode-selective (NMS) multiplexers (muxes) are highly desirable for coherent power combining to produce a high-power beam with a shaped profile (wavefront synthesis) from discrete, phase-locked emitters. We propose a design for a multi-plane light conversion (MPLC)-based NMS mux, which requires only a few phase masks for coherently combining hundreds of discrete input beams into an output beam consisting of hundreds of Hermite–Gaussian (HG) modes. The combination of HG modes as a base can further construct a beam with arbitrary wavefront. The low number of phase masks is attributed to the identical zero-crossing structure of the Hadamard-coded input arrays and of the output HG modes, enabling the practicality of such devices. An NMS mux supporting 256 HG modes is designed using only seven phase masks, and achieves an insertion loss of , mode-dependent loss of 4.7 dB, and average total mode crosstalk of . Additionally, this design, featuring equal power for all input beams, enables phase-only control in coherent power combining, resulting in significant simplifications and fast convergence compared with phase-and-amplitude control.
Photonics Research
2021, 9(2): 02000088
南昌航空大学材料科学与工程学院,南昌 330063
采用微波烧结制备了0.6Ca0.61La0.26TiO3-0.4La(Mg0.5Ti0.5)O3［0.6CLT-0.4LMT］陶瓷,研究烧结工艺对其显微结构和晶粒生长行为的影响,并采用线性回归方法建立了Hillert模型和Sellars简化模型,采用非线性回归方法建立了具有时间指数的Sellars-Anelli模型。结果表明,随着烧结温度的升高、保温时间越长,晶粒尺寸越大,且烧结温度对晶粒生长的影响更为明显。对三种模型预测的晶粒尺寸与实验结果的平均晶粒尺寸进行了误差分析,发现Hillert模型对该陶瓷的预测精度最低,Sellars-Anelli模型对该陶瓷的预测精度最高。由Sellars-Anelli模型得到的0.6CLT-0.4LMT陶瓷的晶粒生长动力学方程为d4.718=d4.7180+4.516×1033×t0.888×exp,能够有效预测0.6CLT-0.4LMT陶瓷微波烧结的晶粒生长过程。
微波烧结 介质陶瓷 线性回归 非线性回归 晶粒生长 生长动力学模型 microwave sintering dielectric ceramics linear regression nonlinear regression grain growth growth kinetic model
Author Affiliations
Abstract
CREOL, The College of Optics & Photonics, University of Central Florida, Orlando, FL 32816, USA
Space-division multiplexing (SDM) has attracted significant attention in recent years because larger transmission capacity is enabled by more degrees of freedom (DOFs) in few-mode fibers (FMFs) compared with single-mode fibers (SMFs). To transmit independent information on spatial modes without or with minor digital signal processing (DSP), weakly-coupled FMFs are preferred in various applications. Several cases with different use of spatial DOFs in weakly-coupled FMFs are demonstrated in this work, including single-mode or mode-group-multiplexed transmission, and spatial DOFs combined with time or frequency DOF to improve the system performance.
multiplexing nonlinear optics fibers radio frequency photonics fiber optics links and subsystems few-mode fibers Chinese Optics Letters
2020, 18(4): 040601
Author Affiliations
Abstract
1 University of Science and Technology of China, 230026, P. R. China
2 Chinese Academy of Sciences, Suzhou Institute of Biomedical, Engineering and Technology, Jiangsu Key Laboratory of Medical Optics, 215163, P. R. China
Melanoma, characterized by high mortality, rapid development and accompanied with angiogenesis is the most typical malignant tumor in skin cancer. Hence, the detection of blood vessels is of much significance. The early vascular network has small scale. If we remove the tumor early and biopsy it, it will increase the spread of the cancer cells and infection and bleeding. In this case, we presented a new angiography method. A high-resolution OCT system for noninvasive angiographic imaging of early skin melanoma — Swept Source Optical Coherence Tomography Angiography (SS-OCTA) is proposed. With a high lateral resolution of 10 μm in vivo tomographic angiography, SS-OCTA is used to image and identify the morphology of the early tumor blood vessels. In addition, a control group experiment is conducted to observe the growth of melanoma in the process of rupture, malformation of micro-vessels. The results of the analysis and statistical test (P < 0:05) are statistically significant.
Melanoma swept source optical coherence tomography angiogra early vessels Journal of Innovative Optical Health Sciences
2019, 12(4): 1942005
Author Affiliations
Abstract
1 CREOL, The College of Optics & Photonics, University of Central Florida, Orlando, Florida 32816-2700, USA
2 Changchun University of Science and Technology, Changchun 130012, China
3 e-mail: li@ucf.edu
We propose a mode demultiplexing hybrid (MDH) that integrates mode demultiplexing, local oscillator power splitting, and optical 90-deg mixing using multi-plane light conversion (MPLC). We demonstrate the realization of a three-mode MDH using four phase plates, one more than what is required for an MPLC-based mode demultiplexer, via numerical simulations. The performance of the three-mode MDH is comparable to that of commercial single-mode 90-deg hybrids. This multiple-functionality device enables simplification of the coherent optical front end of mode-division multiplexing receivers.
Photonics Research
2019, 7(8): 08000917
南京邮电大学 通信与信息工程学院, 南京 210003
建立螺旋凹槽结构模型, 具有不同自旋角动量的光束入射到该结构后激发表面等离激元, 螺旋凹槽结构的螺旋性与光子自旋角动量耦合, 使得不同自旋偏振光激发的表面等离激元具有不同的强度分布.通过螺旋凹槽激发的表面等离激元的强度分布获得入射光的自旋角动量.利用有限元方法计算了左旋偏振光与右旋偏振光激发的表面等离激元在螺旋凹槽中心的光场强度比, 最大消光比达到168, 实现对光子的自旋角动量的检测.在数值仿真中, 分析了不同入射光波长的消光比, 入射光波长在600~740 nm范围内消光比高于50, 其中入射光波长为670 nm时的检测效果最佳; 此外, 研究螺旋凹槽结构参量对消光比的影响, 当凹槽宽度为200 nm,凹槽深度为70 nm, 匝数为2时, 消光比最大, 螺旋凹槽结构检测光子自旋角动量的能力最强.该研究可为集成光学中光子自旋角动量的检测提供一种新途径.
表面等离激元 自旋角动量 有限元方法 螺旋凹槽结构 偏振 消光比 Surface plasmons Spin angular momentum Finite element method Spiral groove structure Polarization Extinction ratio
江西理工大学机电工程学院, 江西 赣州 341000
通过等离子喷涂方法在45
#钢表面涂覆了Fe基Ni/WC金属陶瓷涂层,采用4种激光重熔轨迹对涂层进行了重熔处理,分析了激光重熔轨迹对涂层组织和性能的影响。结果表明,圆形激光重熔轨迹对涂层性能改善效果最显著,在对流传质作用下基体和重熔层之间发生元素转移,基体与重熔层之间的结合方式由机械结合转变为冶金结合;WC、W2C等硬质相在熔覆层中起到弥散强化作用,圆形激光重熔轨迹涂层的显微硬度和磨损失重分别是打点激光重熔轨迹涂层的1.4倍和33.7%;圆形激光重熔轨迹涂层中的孔隙率最小。
激光技术 激光重熔 等离子喷涂 Fe基Ni/WC涂层 扫描轨迹 激光与光电子学进展
2018, 55(4): 041404
