中国计量大学计量测试工程学院，浙江 杭州 310018
针对共程Tolansky干涉测量中出现的干涉圆环嵌套问题，基于多光束反射原理建立了分析模型，通过将MATLAB的仿真实验和实体双臂Tolansky干涉系统相结合的方式进行交叉验证，结果显示嵌套环确实是由光束在干涉分光镜和干涉反射镜之间来回反射产生的多光束干涉造成的。由仿真和实验的验证显示可知，通过合理调整干涉分光镜的透射率、反射率和干涉反射镜的反射率可以对嵌套现象进行有效地抑制，为后续利用共程Tolansky干涉进行精密测量提供了理论和实验指导。
物理光学 Tolansky干涉 共程干涉 非定域 圆环嵌套
江南大学 电子工程系 物联网技术应用教育部工程研究中心, 江苏 无锡 214122
针对传统四相时钟发生电路产生的时钟波形信号易发生交叠、驱动电荷泵易发生漏电等问题, 提出了一种占空比可调四相时钟发生电路。电路在每两相可能出现交叠的时钟信号之间都增加了延时单元模块, 通过控制延时时间对输出时钟信号的占空比进行调节, 避免了时钟相位的交叠。对延时单元进行了改进, 在外接偏置电压条件下, 实现了延时可控。基于55 nm CMOS工艺的仿真结果表明, 在10~50 MHz时钟输入频率范围内, 该四相时钟发生电路可以稳定输出四相不交叠时钟信号, 并能在12 V电压下驱动十级电荷泵高效泵入112 V。流片测试结果表明, 该四相时钟发生电路能够产生不相交叠的四相时钟波形, 时钟输出相位满足电荷泵驱动需求。
电荷泵 四相时钟电路 延时单元 charge pump four-phase clock circuit delay time
1 苏州科技大学 物理科学与技术学院 江苏省微纳热流技术与能源应用重点实验室, 江苏 苏州 215009
2 苏州明世光学科技有限公司, 江苏 苏州 215127
3 江苏省研究生工作站苏州苏大明世光学股份有限公司, 江苏 苏州 215127
为了产生半径可自由调控的聚焦环形激光且确保离焦后光束强度仍均匀，本文提出一种透射-反射式组合的环形光光学系统设计方法。对于透射式系统，基于等能量分割原理，建立入射光与出射光投射高度的映射函数，优化透镜的各项参数，将入射的高斯光先整形成平顶圆形光，实现光束强度均匀化。反射式系统通过调整焦面环形光直径调控范围、工作距离等参数，结合几何光线追迹原理，计算圆锥反射镜、抛物柱面镜及动镜的各项参数，将平顶圆形光再整形成环形光。实验结果表明：当动镜半顶角为16°时，所设计系统能够实现聚焦环形光半径在15~30 mm范围的自由调控，尺寸误差不超过0.05 mm，离焦后强度均匀度达到84%。该设计方法无需更换系统镜片即可兼顾强度均匀性和尺寸自由度，可操作性好，产生的环形光加工精度和效率更高。
光学系统 环形激光 半径调控 离焦均匀 optical system ring-shaped laser radius control defocus uniformity 
Author Affiliations
Abstract
1 Microsystems and Nanotechnology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
2 Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
3 e-mail: xiyuan.lu@nist.gov
Frequency engineering of whispering-gallery resonances is essential in microcavity nonlinear optics. The key is to control the frequencies of the cavity modes involved in the underlying nonlinear optical process to satisfy its energy conservation criterion. Compared to the conventional method that tailors dispersion by cross-sectional geometry, thereby impacting all cavity mode frequencies, grating-assisted microring cavities, often termed as photonic crystal microrings, provide more enabling capabilities through mode-selective frequency control. For example, a simple single period grating added to a microring has been used for single frequency engineering in Kerr optical parametric oscillation (OPO) and frequency combs. Recently, this approach has been extended to multi-frequency engineering by using multi-period grating functions, but at the cost of increasingly complex grating profiles that require challenging fabrication. Here, we demonstrate a simple approach, which we term as shifted grating multiple mode splitting (SGMMS), where spatial displacement of a single period grating imprinted on the inner boundary of the microring creates a rotational asymmetry that frequency splits multiple adjacent cavity modes. This approach is easy to implement and presents no additional fabrication challenges compared to an un-shifted grating, and yet is very powerful in providing multi-frequency engineering functionality for nonlinear optics. We showcase an example where SGMMS enables OPO across a wide range of pump wavelengths in a normal-dispersion device that otherwise would not support OPO.
Photonics Research
2023, 11(11): A72
黄家俊 1,2,3,*李月明 1,2,3孙熠 1,2,3李恺 1,2,3王竹梅 1,2,3
1 景德镇陶瓷大学材料科学与工程学院, 江西 景德镇333403
2 中国轻工业功能陶瓷材料重点实验室, 江西 景德镇333403
3 江西省能量存储与转换陶瓷材料工程实验室, 江西 景德镇333403
为了更好的满足无线通讯高频化的要求, 采用固相法制备了温度系数近零的(1-x)MgNb2O6-xCaTiO3(x=0, 0.02, 0.04, 0.08, 0.12, 0.16)微波介质陶瓷。研究了CaTiO3的加入量对MgNb2O6微观结构和介电性能的影响, 探究各物相的形成和烧结行为。结果表明: 适当的CaTiO3加入量能够促进MgNb2O6的烧结, 降低了烧结温度。通过X射线衍射分析, CaTiO3与MgNb2O6在高温时会反应生成CaNb2O6和Ti8O15、Ti2Nb10O29。增加CaTiO3的加入量, 会降低陶瓷的品质因数Q×f, 但同时会提高其介电常数εr和频率温度系数τf。当CaTiO3的添加量x=0.16时, 样品在1 250 ℃烧结4 h后具有最佳的微波介电性能: εr=21.6, Q×f=86 601 GHz, τf=-7.3×10-6/℃。
微波介质陶瓷 正温度系数材料 温度频率系数 微波介电性能 microwave dielectric ceramics positive temperature coefficient material temperature coefficient microwave dielectric properties
Author Affiliations
Abstract
1 Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
2 Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
3 Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
Nonlinear optical imaging is a versatile tool that has been proven to be exceptionally useful in various research fields. However, due to the use of photomultiplier tubes (PMTs), the wide application of nonlinear optical imaging is limited by the incapability of imaging under ambient light. In this paper, we propose and demonstrate a new optical imaging detection method based on optical parametric amplification (OPA). As a nonlinear optical process, OPA intrinsically rejects ambient light photons by coherence gating. Periodical poled lithium niobate (PPLN) crystals are used in this study as the media for OPA. Compared to bulk nonlinear optical crystals, PPLN crystals support the generation of OPA signal with lower pump power. Therefore, this characteristic of PPLN crystals is particularly beneficial when using high-repetition-rate lasers, which facilitate high-speed optical signal detection, such as in spectroscopy and imaging. A PPLN-based OPA system was built to amplify the emitted imaging signal from second harmonic generation (SHG) and coherent anti-Stokes Raman scattering (CARS) microscopy imaging, and the amplified optical signal was strong enough to be detected by a biased photodiode under ordinary room light conditions. With OPA detection, ambient-light-on SHG and CARS imaging becomes possible, and achieves a similar result as PMT detection under strictly dark environments. These results demonstrate that OPA can be used as a substitute for PMTs in nonlinear optical imaging to adapt it to various applications with complex lighting conditions.Nonlinear optical imaging is a versatile tool that has been proven to be exceptionally useful in various research fields. However, due to the use of photomultiplier tubes (PMTs), the wide application of nonlinear optical imaging is limited by the incapability of imaging under ambient light. In this paper, we propose and demonstrate a new optical imaging detection method based on optical parametric amplification (OPA). As a nonlinear optical process, OPA intrinsically rejects ambient light photons by coherence gating. Periodical poled lithium niobate (PPLN) crystals are used in this study as the media for OPA. Compared to bulk nonlinear optical crystals, PPLN crystals support the generation of OPA signal with lower pump power. Therefore, this characteristic of PPLN crystals is particularly beneficial when using high-repetition-rate lasers, which facilitate high-speed optical signal detection, such as in spectroscopy and imaging. A PPLN-based OPA system was built to amplify the emitted imaging signal from second harmonic generation (SHG) and coherent anti-Stokes Raman scattering (CARS) microscopy imaging, and the amplified optical signal was strong enough to be detected by a biased photodiode under ordinary room light conditions. With OPA detection, ambient-light-on SHG and CARS imaging becomes possible, and achieves a similar result as PMT detection under strictly dark environments. These results demonstrate that OPA can be used as a substitute for PMTs in nonlinear optical imaging to adapt it to various applications with complex lighting conditions.
Nonlinear optical microscopy optical parametric amplification optical detection Journal of Innovative Optical Health Sciences
2023, 16(1): 2245001
1 景德镇陶瓷大学材料科学与工程学院, 中国轻工业功能陶瓷材料重点实验室, 江西景德镇 333403
2 中国建筑材料科学研究总院, 北京 100024
以福建龙岩高岭土、安徽钾长石、江西星子石英为陶瓷主要原料, 添加适量的硅酸锆为增强相, 研究了硅酸锆引入量、烧成温度、保温时间等因素对日用陶瓷性能的影响, 探究了硅酸锆颗粒弥散分布对日用陶瓷的强化机理。结果表明: 当引入硅酸锆含量为 6% (质量分数 ), 烧成温度为 1 300℃、保温时间为 30 min时, 强化效果最好, 抗弯强度从基础配方的(58±6) MPa提升至(106±11) MPa, 提升幅度为 83%。硅酸锆颗粒弥散分布在基体内部, 由于其与基体热膨胀系数的差异, 冷却过程中在基体内部产生径向压应力与切向张应力, 使裂纹在颗粒处钉扎, 从而提高了陶瓷强度。
日用陶瓷 硅酸锆 预应力 基体强化 porcelain zirconium silicate prestress matrix reinforcement
任德威 1,2,3,4,*李月明 1,2,3,4王竹梅 1,2,3,4李恺 1,2,3,4[ ... ]宋福生 1,2,3,4
1 景德镇陶瓷大学材料科学与工程学院
2 中国轻工业功能陶瓷材料重点实验室
3 江西省能量存储与转换陶瓷材料工程实验室
4 江西 景德镇 333403
γ-Ce2S3是一种无毒环保型大红无机色料，色泽鲜艳、遮盖力强、具有优异的抗紫外能力，但其抗氧化温度为350 ℃。为提升γ-Ce2S3大红色料的抗氧化温度，采用溶胶-凝胶法结合硫化升温工艺，合成了莫来石包裹的Na+掺杂型γ-Ce2S3大红色料 (记为γ-［Na］-Ce2S3@mullite)，研究了莫来石的合成条件、不同预烧温度对包裹色料前驱体形貌以及色度的影响，并分析了包裹色料的温度稳定性。结果表明：当烧结温度为1 300 ℃保温3 h、n(Al):n(Si)=3.2:2.0(n为摩尔)时，可合成短棒状和类球状的莫来石晶体；当预烧温度为400 ℃，可获得最佳色度值的包裹色料：L*=36.24、a*=41.86、b*=36.26，该色料在空气气氛下800 ℃保温10 min仍具有良好的色度值：L*=29.84、a*=20.83、b*=18.17，表明γ-［Na］-Ce2S3@mullite可使γ-Ce2S3的温度稳定性从350 ℃提升至800 ℃。
伽马硫化铈 溶胶-凝胶法 莫来石包裹色料 gamma cerium sulphide sol-gel method mullite coating pigments 
Author Affiliations
Abstract
Wide Bandgap Semiconductor Technology Disciplines State Key Laboratory, Xidian University, Xi’an 710071, China
The high-power microwave (HPM) effect heats solar cells, which is an important component of a satellite. This creates a serious reliability problem and affects the normal operation of a satellite. In this paper, the different HPM response characteristics of two kinds of solar cells are comparatively researched by simulation. The results show that there are similarities and differences in hot spot distribution and damage mechanisms between both kinds of solar cell, which are related to the amplitude of HPM. In addition, the duty cycle of repetition frequency contributes more to the temperature accumulation of the solar cells than the carrier frequency. These results will help future research of damage assessment technology, reliability enhancement and the selection of materials for solar cells.The high-power microwave (HPM) effect heats solar cells, which is an important component of a satellite. This creates a serious reliability problem and affects the normal operation of a satellite. In this paper, the different HPM response characteristics of two kinds of solar cells are comparatively researched by simulation. The results show that there are similarities and differences in hot spot distribution and damage mechanisms between both kinds of solar cell, which are related to the amplitude of HPM. In addition, the duty cycle of repetition frequency contributes more to the temperature accumulation of the solar cells than the carrier frequency. These results will help future research of damage assessment technology, reliability enhancement and the selection of materials for solar cells.
Journal of Semiconductors
2022, 43(11): 112701
