Prof. Weiqian Zhao Profile

Prof. Weiqian Zhao

at Beijing Institute of Technology

SPIE Involvement:

Author

Publications (31)

Proceedings Article | 29 November 2023 Poster

Research on the method of determining the number of layers and mapping of two-dimensional materials based on high-precision confocal Raman spectroscopy

Angze Li, Xiaojuan Chuai, Han Cui, Lirong Qiu, Weiqian Zhao

Proceedings Volume 12767, 1276714 (2023) https://doi.org/10.1117/12.2686946

KEYWORDS: Raman spectroscopy, 2D materials, Confocal microscopy, Molybdenum, Silicon, Laser systems engineering, Imaging spectroscopy, Spectroscopy, Spatial resolution, Reflection

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Proceedings Article | 29 November 2023 Poster

A laser confocal vibration signal processing method based on wavelet transform

Demin Xu, Yuebo Wu, Lirong Qiu, Ke-Mi Xu, Weiqian Zhao

Proceedings Volume 12769, 1276919 (2023) https://doi.org/10.1117/12.2686959

KEYWORDS: Vibration, Signal processing, Confocal microscopy, Wavelet transforms, Laser processing, Signal to noise ratio, Wavelets, Denoising, Vibrometry, Signal intensity

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Proceedings Article | 29 November 2023 Poster

Portable confocal-controlled LIBS microscopy based on MEMS mirror scanning

Xu Wang, Bo Peng, Han Cui, Yun Wang, Weiqian Zhao, Hongyan Deng, Lirong Qiu

Proceedings Volume 12767, 1276713 (2023) https://doi.org/10.1117/12.2686945

KEYWORDS: Mirrors, Microelectromechanical systems, Laser induced breakdown spectroscopy, Portability, Microscopy, Signal detection, Miniaturization, Aspheric lenses, Spatial resolution, Objectives

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Proceedings Article | 24 November 2023 Paper

Research of femtosecond laser-assisted etching of fused silica micro-optics devices

Hongsheng Quan, Weifeng Ma, Yujin Cai, Kemi Xu, Weiwei Xu, Weiqian Zhao

Proceedings Volume 12935, 1293517 (2023) https://doi.org/10.1117/12.3005763

KEYWORDS: Diffraction gratings, Zone plates, Silica, Laser processing, Femtosecond phenomena, Microlens array, Etching

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Fused silica is widely used in aerospace and precision integrated micro-optical sensors due to its high hardness, low coefficient of thermal expansion, high transmittance properties and high chemical stability in harsh environments. Due to the amorphous characteristics, fused silica wet etching is isotropic and cannot realize specific structural functional devices; dry etching process is complex, costly, and relatively low productivity. These characteristics make the processing of fused silica extremely difficult, with high cost and low yield. Femtosecond laser processing has been widely used in the processing of complex and fine three-dimensional structure of fused silica due to its wide adaptability of materials, high degree of processing fineness and non-mask processing technology, but the surface of the processed surface is relatively rough. Fine micro-optical devices can be realized by wet-assisted femtosecond laser processing. In this study, microstructural patterns were fabricated on fused silica using a tightly focused femtosecond laser by means of a self-developed ultrafast laser processing instrumentation. By controlling the laser processing parameters and the etching time of HF solution to realize the precise modulation of linewidth, period and height of the grating, one/two dimensional gratings, and the Fresnel zone plates with circular and elliptical focal points and the biomimetic compound eye microlens array were successfully fabricated. Finally, the performance of the fabricated optical components were characterized, which were comparable to theoretical simulation values. The results show that the total diffraction efficiency of the fused silica gratings fabricated using this method reaches 85.5%; the Fresnel zone plates and the bionic compound eye microlens array have good focusing effects. This study provides a reference method for the fine micromachining of hard materials such as fused silica, and provides a theoretical basis for its engineering application.

Proceedings Article | 24 November 2023 Paper

Research on laser confocal free-form surface measurement method based on adaptive ant colony algorithm

Xiaoxue Zhu, Yuhan Liu, Lirong Qiu, Weiqian Zhao

Proceedings Volume 12935, 129352Z (2023) https://doi.org/10.1117/12.3007704

KEYWORDS: Confocal microscopy, Sensors, Design and modelling, Detection and tracking algorithms, Objectives, Aspheric lenses, Optical surfaces, Laser soldering, Laser applications, Data acquisition

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Proceedings Article | 9 January 2023 Poster

In-situ topographic characterization and mechanical mapping by divided-aperture confocal Brillouin microscopy

Yunhao Su, Weiqian Zhao, Lirong Qiu

Proceedings Volume 12316, 123160I (2023) https://doi.org/10.1117/12.2655746

KEYWORDS: Confocal microscopy, Microscopy, Light scattering, Spatial resolution, Tissues, Microscopes, Imaging systems, Associative arrays, Scattering, Materials science

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Proceedings Article | 9 January 2023 Poster

Miniaturized confocal Raman microscopy based on MEMS mirror scanning

Guozhuo Zhang, Xu Wang, Han Cui, Weiqian Zhao

Proceedings Volume 12316, 123160J (2023) https://doi.org/10.1117/12.2655747

KEYWORDS: Confocal microscopy, Raman spectroscopy, Mirrors, Microelectromechanical systems, Microscopy, Spectral resolution, Microscopes, Signal detection, Optical scanning systems, Aspheric lenses

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Proceedings Article | 5 January 2023 Poster

Three-dimensional high-precision mineral mapping using confocal controlled LIBS microscope

Chunjing He, Angze Li, Lirong Qiu, Weiqian Zhao

Proceedings Volume 12316, 123160H (2023) https://doi.org/10.1117/12.2655745

KEYWORDS: Laser induced breakdown spectroscopy, Minerals, Confocal microscopy, Microscopes, Multi-element lenses, Chemical elements, Spatial resolution, Principal component analysis, Chemometrics

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Laser induced breakdown spectroscopy (LIBS) termed an effective technique to confirm the elemental composition of geologic, due to its unique elemental ‘fingerprint’ properties and qualitative or quantitative analytical performance. However, the low focusing accuracy and poor spatial resolution of traditional LIBS technology limits its application in minerals with complex topography. To address this issue, we constructed a confocal controlled LIBS (CCLIBS) microscope for three-dimensional elemental mapping of natural minerals. The CCLIBS system is an innovative fusion of confocal microscopy and LIBS technology, which significantly improves the spatial resolution and the stability of LIBS spectrum. With this system, the geometry and elemental distribution of natural agate ores are accurately obtained. Then, a common chemometric method of principal component analysis (PCA) was conducted to analyse the differences in such spectral lines. According to the differences of wavelength and intensity characteristics, the typical spectra were selected to map the elemental distribution. Finally, the three elements with the highest PC scores were selected to construct the multi-element fusion mapping, which can reflect the distribution of elements more intuitively. In this paper, we innovatively integrate three-dimensional (3D) morphology with multi-element distribution to characterize the spatial distribution of elements. Compared with single-element fusion, multi-element fusion is more intuitive and clearer, which is of great significance for the analysis of complex components of natural minerals. To solve the problems of low focusing accuracy and poor spatial resolution of traditional LIBS technology, we constructed a confocal controlled LIBS microscope for three-dimensional elemental mapping of natural minerals. The microscope is an innovative fusion of confocal microscopy and LIBS technology, which significantly improves the spatial resolution and stability of spectrum, ensuring that the system can achieve minimal ablation at focal point. Furthermore, we integrate three-dimensional (3D) morphology with multi-element distribution to characterize the spatial distribution of elements. The innovative method provides an effective way for elemental characterization in the fields of biomedicine, materials science and geological science.

Proceedings Article | 21 December 2022 Presentation

Freeform surface measurement by virtual differential confocal based on reference planes monitoring

Wenbin Wang, Lirong Qiu, Weiqian Zhao

Proceedings Volume 12319, 123190A (2022) https://doi.org/10.1117/12.2656177

KEYWORDS: Confocal microscopy, Data modeling, 3D modeling, Signal processing, Precision measurement, Clouds, 3D metrology, Surface roughness, Sensors, Photovoltaics

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Proceedings Article | 6 November 2018 Paper

Accuracy evaluations of axial localisation algorithms in confocal microscopy

Rongjun Shao, Weiqian Zhao, Lirong Qiu, Yun Wang, Ruirui Zhang

Proceedings Volume 10819, 108191O (2018) https://doi.org/10.1117/12.2501031

KEYWORDS: Confocal microscopy, Signal to noise ratio, Monochromatic aberrations, Error analysis, Metrology, Sensors, Interference (communication), Optoelectronics, Microscopes

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Proceedings Article | 10 February 2017 Paper

Research on virtual pinhole parameters optimization in laser differential confocal theta microscope

Xiangye Zhao, Yun Wang, Lirong Qiu, Weiqian Zhao, Ke Zhu

Proceedings Volume 10250, 102501Y (2017) https://doi.org/10.1117/12.2266831

KEYWORDS: Confocal microscopy, Microscopes, Optoelectronics, Precision measurement, Stereoscopy, Image resolution

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Proceedings Article | 8 October 2015 Paper

Laser differential reflection-confocal lens thickness measurement

Nan Zhou, Yun Wang, Weiqian Zhao, Lirong Qiu, Lingfeng Chen

Proceedings Volume 9677, 96771I (2015) https://doi.org/10.1117/12.2199689

KEYWORDS: Optical testing, Reflectors, Error analysis, Confocal microscopy, Distance measurement, Sensors, Precision measurement, Interferometers, Refractive index, Beam splitters

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Proceedings Article | 5 August 2015 Paper

Lens central thickness measurement by laser reflection-confocal technology

Lirong Qiu, Yongkui Guo, Weiqian Zhao, Yang Xiao

Proceedings Volume 9618, 961806 (2015) https://doi.org/10.1117/12.2193394

KEYWORDS: Reflectors, Laser applications, Ray tracing, Calibration, Confocal microscopy, Lawrencium, Capacitors, Sensors, Collimation, Refractive index

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Proceedings Article | 5 August 2015 Paper

The method of axial drift compensation of laser differential confocal microscopy based on zero-tracking

Yajie Wang, Han Cui, Yun Wang, Lirong Qiu, Weiqian Zhao

Proceedings Volume 9618, 96180X (2015) https://doi.org/10.1117/12.2193289

KEYWORDS: Confocal microscopy, Sensors, Ferroelectric materials, Microscopes, Environmental sensing, Optical testing, Laser applications, Time metrology, Image resolution, Visualization

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Proceedings Article | 6 March 2015 Paper

Laser confocal measurement system for curvature radius of lenses based on grating ruler

Jiwei Tian, Yun Wang, Nan Zhou, Weirui Zhao, Weiqian Zhao

Proceedings Volume 9446, 94462T (2015) https://doi.org/10.1117/12.2181193

KEYWORDS: Confocal microscopy, Calibration, Laser development, Laser systems engineering, Distance measurement, Metrology, Interferometers, Lenses, Precision measurement, Optical metrology

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Proceedings Article | 6 March 2015 Paper

Development of ultra-precision centering and leveling turntable using aerostatic bearing technology

Maosheng Hou, Yanrong Tian, Lin Ji, Longxiao Wang, Jiaqi Liu, Weiqian Zhao

Proceedings Volume 9446, 94463A (2015) https://doi.org/10.1117/12.2181345

KEYWORDS: Actuators, Spherical lenses, Precision measurement, Mathematical modeling, Optical testing, Precision optics, Error analysis, Reflectors, Autocollimators, Control systems

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Proceedings Article | 6 March 2015 Paper

Image inpainting for the differential confocal microscope

Lirong Qiu, Lei Wang, Dali Liu, Maosheng Hou, Weiqian Zhao

Proceedings Volume 9446, 94463D (2015) https://doi.org/10.1117/12.2181352

KEYWORDS: Confocal microscopy, Microscopes, Image restoration, Signal detection, Image quality, Optical simulations, Statistical modeling, Computer simulations, Sensors, Laser damage threshold

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Proceedings Article | 19 February 2015 Paper

High-precision radius automatic measurement using laser differential confocal technology

Hongwei Jiang, Weiqian Zhao, Jiamiao Yang, Yongkui Guo, Yang Xiao

Proceedings Volume 9449, 944935 (2015) https://doi.org/10.1117/12.2081341

KEYWORDS: Confocal microscopy, Eye, Precision measurement, Composites, Laser applications, Environmental sensing, Time metrology, Control systems, Motion measurement, Interferometers

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Proceedings Article | 18 September 2014 Paper

High-frequency angular vibration calibration using the mirror assembly diffraction grating heterodyne laser interferometer

Jingfeng Xue, Dazhi Zhang, Xinliang Li, Weiqian Zhao

Proceedings Volume 9282, 928219 (2014) https://doi.org/10.1117/12.2067780

KEYWORDS: Calibration, Interferometers, Diffraction gratings, Sensors, Mirrors, Heterodyning, Sensor calibration, Vibrometry, Doppler effect, Laser applications

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Proceedings Article | 28 May 2014 Paper

Study on the stitching interferometry for the surface profile measurement of a large aperture component

Weirui Zhao, Lirong Qiu, Weiqian Zhao, Genrui Cao

Proceedings Volume 9110, 91100W (2014) https://doi.org/10.1117/12.2053182

KEYWORDS: Wavefronts, Stitching interferometry, Mirrors, Zernike polynomials, Interferometers, Phase shifts, Phase shifting, Computing systems, Spherical lenses, Optoelectronics

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Proceedings Article | 23 December 2013 Paper

A data processing method based on tracking light spot for the laser differential confocal component parameters measurement system

Rongjun Shao, Lirong Qiu, Jiamiao Yang, Weiqian Zhao, Xin Zhang

Proceedings Volume 9043, 90430L (2013) https://doi.org/10.1117/12.2034881

KEYWORDS: Confocal microscopy, Gaussian filters, Data processing, Interferometers, Laser processing, Signal processing, Charge-coupled devices, Interference (communication), Microscopes, Digital imaging

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SPIE Journal Paper | 23 October 2013

Confocal multiple-transmitted-light interference microscope with increased lateral resolution

Lirong Qiu, Weiqian Zhao

OE, Vol. 52, Issue 10, 100504, (October 2013) https://doi.org/10.1117/12.10.1117/1.OE.52.10.100504

KEYWORDS: Confocal microscopy, Microscopes, Curium, Point spread functions, Objectives, Reflectivity, Near field optics, Optical engineering, Telescopes, Optoelectronics

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Proceedings Article | 10 October 2013 Paper

Measuring the lens focal length by laser confocal technique

Hualing Wu, Jiamiao Yang, Liurong Qiu, Weiqian Zhao

Proceedings Volume 8916, 89161E (2013) https://doi.org/10.1117/12.2035803

KEYWORDS: Reflectors, Confocal microscopy, Interferometry, Laser applications, Beam splitters, Interferometers, Sensors, Phase interferometry, Fiber optics, Optical testing

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Proceedings Article | 31 January 2013 Paper

Dual-axes tri-differential confocal sensing technique with higher axial resolution and SNR

Chao Liu, Lirong Qiu, Qin Jiang, Weiqian Zhao

Proceedings Volume 8759, 87593P (2013) https://doi.org/10.1117/12.2014593

KEYWORDS: Confocal microscopy, Sensors, Charge-coupled devices, Signal to noise ratio, CCD image sensors, Curium, Objectives, Microscopy, Molybdenum, Point spread functions

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Proceedings Article | 26 November 2012 Paper

The distortion analysis and correction of two-dimensional scanning system in laser differential confocal microscopy

Chao Gao, Dali Liu, Weiqian Zhao

Proceedings Volume 8557, 85572L (2012) https://doi.org/10.1117/12.999284

KEYWORDS: Mirrors, Distortion, Imaging systems, Confocal microscopy, Mathematical modeling, MATLAB, Mathematics, Laser systems engineering, Systems modeling, Data acquisition

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Proceedings Article | 30 November 2011 Paper

Laser two-dimensional angle dynamic measurement system

Lirong Qiu, Haorong Guo, Yun Wang, Weiqian Zhao

Proceedings Volume 8201, 82010G (2011) https://doi.org/10.1117/12.907158

KEYWORDS: Sensors, Mirrors, Dynamical systems, Laser development, Precision measurement, Imaging systems, Optical testing, Laser applications, Optoelectronics, System integration

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Proceedings Article | 3 February 2009 Paper

Effect of pupil filter position on superresolution properties of confocal measurement system

Lirong Qiu, Weiqian Zhao, Junjie Guo, Dingguo Sha

Proceedings Volume 7160, 716036 (2009) https://doi.org/10.1117/12.812000

KEYWORDS: Confocal microscopy, Super resolution, Imaging systems, Optical filters, 3D microstructuring, Curium, Phase only filters, Sensors, Spatial resolution, Objectives

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Proceedings Article | 6 November 2006 Paper

A three-zone pulse-only pupil filter for improving lateral resolution

Lirong Qiu, Weiqian Zhao, Dingguo Sha

Proceedings Volume 6357, 63573Z (2006) https://doi.org/10.1117/12.717271

KEYWORDS: Super resolution, Phase only filters, Optical filters, Imaging systems, Image filtering, Curium, Optical imaging, Image resolution, Genetic algorithms, Confocal microscopy

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SPIE Journal Paper | 1 November 2006

Approach to higher spatial resolutions in a laser probe measurement system using a phase-only pupil filter

Lirong Qiu, Weiqian Zhao, Zhengde Feng, Xuemei Ding

OE, Vol. 45, Issue 11, 113601, (November 2006) https://doi.org/10.1117/12.10.1117/1.2388944

KEYWORDS: Spatial resolution, Confocal microscopy, Optical filters, Super resolution, Phase only filters, Sensors, Signal detection, Laser beam diagnostics, Laser systems engineering, Optical engineering

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Proceedings Article | 10 October 2000 Paper

Development of research on super-precision measurement techniques for circle and cylindrical contour

Jiubin Tan, Weiqian Zhao, Wenguo Yang

Proceedings Volume 4222, (2000) https://doi.org/10.1117/12.403871

KEYWORDS: Error analysis, Confocal microscopy, Laser applications, Precision measurement, Standards development, Computing systems, Nanotechnology, Sensors, Beam splitters, Optical testing

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