针对光学元件研磨阶段传统单测头检测方法对机床导轨运动误差敏感,难以同时兼顾检测精度与在位测量效率的问题,提出一种适用于普通机床集成条件下的多测头非接触式面形检测方法,以实现光学元件研磨阶段的高精度在位检测。阐述由3个激光...针对光学元件研磨阶段传统单测头检测方法对机床导轨运动误差敏感,难以同时兼顾检测精度与在位测量效率的问题,提出一种适用于普通机床集成条件下的多测头非接触式面形检测方法,以实现光学元件研磨阶段的高精度在位检测。阐述由3个激光位移传感器组成的多测头系统的差分检测原理,通过三测头两两差分抑制机床导轨运动误差,并将位移差分量转换为被测面局部斜率信息,再基于Zernike多项式的斜率拟合与面形重建原理,利用最小二乘拟合由斜率场反演得到全口径面形。建立系统的几何仿真模型,采用蒙特卡罗法分析测头位置误差和姿态误差对面形重构结果的影响,进一步引入Sobol全局敏感度系数量化各误差源对均方根(Root Mean Square,RMS)误差的贡献,为系统装调公差分配和误差控制策略提供依据。最后,对一片口径为Φ400 mm、材料为单晶硅的研磨阶段平面反射镜进行实验验证,将本研究的检测结果与三坐标测量机(Coordinate Measuring Machine,CMM)的检测结果进行对比。实验结果表明,两种方法得到的峰谷值(Peak to Valley,PV)值绝对偏差为0.21μm,相对偏差为2.22%;RMS值绝对偏差为0.14μm,相对偏差为7.78%。所提方法可保持良好的测量一致性和稳定性,为光学元件研磨阶段的高精度面形检测提供了一种易于工程实现的解决方案。展开更多
在相机和旋转模块组成的旋转扫描系统中,相机与转轴的位姿关系对于后续数据融合至关重要。现有方法通常需借助辅助传感器来建立转轴与相机的位姿关系。为降低标定成本,本文提出一种基于ChArUco(Chess Augmented Reality University of C...在相机和旋转模块组成的旋转扫描系统中,相机与转轴的位姿关系对于后续数据融合至关重要。现有方法通常需借助辅助传感器来建立转轴与相机的位姿关系。为降低标定成本,本文提出一种基于ChArUco(Chess Augmented Reality University of Córdoba)标定板的转轴位姿标定方法。利用ChArUco标定板图像解算不同转角下的相机光心坐标并拟合光心轨迹,根据轨迹中心可确定转轴所在位置。建立了旋转系统的数学模型,推导了在世界坐标系下转轴位姿的数学表达式,并基于旋转系统的空间约束构建联合优化,计算相机和转轴间最佳位姿。利用所提出方法进行旋转相机系统标定实验,实验结果表明:标定后的转轴与相机光轴夹角的平均绝对误差为0.036°,标定结果能有效消除全景拼接时的重影现象,验证了所提出方法的准确性和可行性。展开更多
Metasurfaces are artificial structures that can finely control the characteristics of electromagnetic waves at subwavelength scales,and they are widely used to manipulate the propagation,phase,amplitude,and polariza⁃t...Metasurfaces are artificial structures that can finely control the characteristics of electromagnetic waves at subwavelength scales,and they are widely used to manipulate the propagation,phase,amplitude,and polariza⁃tion of light.In this work,a bound state in the continuum(BIC)structure based on a metallic metasurface is pro⁃posed.By adjusting the metallic structure using CST and COMSOL software,a significant quasi-BIC peak can be achieved at a frequency of 0.8217 terahertz(THz).Through multi-level expansion analysis,it is found that the electric dipole(ED)is the main factor contributing to the resonant characteristics of the structure.By leveraging the characteristics of BIC,an imaging system was created and operated.According to the simulation results,the imaging system demonstrated excellent sensitivity and resolution,revealing the great potential of terahertz imag⁃ing.This research not only provides new ideas for the creation of BIC structures but also offers an effective refer⁃ence for the development of high-performance terahertz imaging technology.展开更多
Topological semimetal materials have garnered significant interest due to their distinctive electronic structures and unique properties.They serve as a foundation for exploring various physical phenomena including the...Topological semimetal materials have garnered significant interest due to their distinctive electronic structures and unique properties.They serve as a foundation for exploring various physical phenomena including the anomalous Hall effect,topological phase transitions and negative magnetoresistance,while also offering po⁃tential solutions to the"THz Gap."This study focuses on the type-II Weyl semimetal tetratellurium iridium niobi⁃um(NbIrTe4)terahertz detector which exhibits a responsivity of 4.36 A/W,a noise equivalent power of 12.34 pW/Hz^(1/2) and an anisotropic resistance ratio of 32 at room temperature.This research paves the way for achieving high-performance terahertz detection at room temperature and serves as a reference for investigating the Weyl semimetal.展开更多
文摘针对光学元件研磨阶段传统单测头检测方法对机床导轨运动误差敏感,难以同时兼顾检测精度与在位测量效率的问题,提出一种适用于普通机床集成条件下的多测头非接触式面形检测方法,以实现光学元件研磨阶段的高精度在位检测。阐述由3个激光位移传感器组成的多测头系统的差分检测原理,通过三测头两两差分抑制机床导轨运动误差,并将位移差分量转换为被测面局部斜率信息,再基于Zernike多项式的斜率拟合与面形重建原理,利用最小二乘拟合由斜率场反演得到全口径面形。建立系统的几何仿真模型,采用蒙特卡罗法分析测头位置误差和姿态误差对面形重构结果的影响,进一步引入Sobol全局敏感度系数量化各误差源对均方根(Root Mean Square,RMS)误差的贡献,为系统装调公差分配和误差控制策略提供依据。最后,对一片口径为Φ400 mm、材料为单晶硅的研磨阶段平面反射镜进行实验验证,将本研究的检测结果与三坐标测量机(Coordinate Measuring Machine,CMM)的检测结果进行对比。实验结果表明,两种方法得到的峰谷值(Peak to Valley,PV)值绝对偏差为0.21μm,相对偏差为2.22%;RMS值绝对偏差为0.14μm,相对偏差为7.78%。所提方法可保持良好的测量一致性和稳定性,为光学元件研磨阶段的高精度面形检测提供了一种易于工程实现的解决方案。
文摘在相机和旋转模块组成的旋转扫描系统中,相机与转轴的位姿关系对于后续数据融合至关重要。现有方法通常需借助辅助传感器来建立转轴与相机的位姿关系。为降低标定成本,本文提出一种基于ChArUco(Chess Augmented Reality University of Córdoba)标定板的转轴位姿标定方法。利用ChArUco标定板图像解算不同转角下的相机光心坐标并拟合光心轨迹,根据轨迹中心可确定转轴所在位置。建立了旋转系统的数学模型,推导了在世界坐标系下转轴位姿的数学表达式,并基于旋转系统的空间约束构建联合优化,计算相机和转轴间最佳位姿。利用所提出方法进行旋转相机系统标定实验,实验结果表明:标定后的转轴与相机光轴夹角的平均绝对误差为0.036°,标定结果能有效消除全景拼接时的重影现象,验证了所提出方法的准确性和可行性。
基金supported by the National Natural Science Foundation of China(61927813,61865009,12104203)Jiangxi Provincial Natu-ral Science Foundation(20212ACB201007)。
文摘Metasurfaces are artificial structures that can finely control the characteristics of electromagnetic waves at subwavelength scales,and they are widely used to manipulate the propagation,phase,amplitude,and polariza⁃tion of light.In this work,a bound state in the continuum(BIC)structure based on a metallic metasurface is pro⁃posed.By adjusting the metallic structure using CST and COMSOL software,a significant quasi-BIC peak can be achieved at a frequency of 0.8217 terahertz(THz).Through multi-level expansion analysis,it is found that the electric dipole(ED)is the main factor contributing to the resonant characteristics of the structure.By leveraging the characteristics of BIC,an imaging system was created and operated.According to the simulation results,the imaging system demonstrated excellent sensitivity and resolution,revealing the great potential of terahertz imag⁃ing.This research not only provides new ideas for the creation of BIC structures but also offers an effective refer⁃ence for the development of high-performance terahertz imaging technology.
基金Supported by the National Natural Science Foundation of China(61865009)the National Natural Science Foundation of China Major Research Equipment Development Project(61927813)。
文摘Topological semimetal materials have garnered significant interest due to their distinctive electronic structures and unique properties.They serve as a foundation for exploring various physical phenomena including the anomalous Hall effect,topological phase transitions and negative magnetoresistance,while also offering po⁃tential solutions to the"THz Gap."This study focuses on the type-II Weyl semimetal tetratellurium iridium niobi⁃um(NbIrTe4)terahertz detector which exhibits a responsivity of 4.36 A/W,a noise equivalent power of 12.34 pW/Hz^(1/2) and an anisotropic resistance ratio of 32 at room temperature.This research paves the way for achieving high-performance terahertz detection at room temperature and serves as a reference for investigating the Weyl semimetal.
