Optical Metrology for Mechanical Engineers: interferometry and holography
报告人: Jeremy Coupland, Loughborough University, UK
时间: 4月20日, 周四 14:00-15:30
地点: B3009, 交叉二号楼
联系人: 张祥朝
Abstract: The commercial development of lasers in the early 1960s provided a step-change in the capability of metrological tools. Interferometric techniques that were previously confined to laboratory configurations with short path length imbalance or comparison of smooth optical components could be used to measure the deformation of large-scale structures with little or no surface treatment. With further development of tuneable sources, fast detectors, high resolution electronic imaging devices and powerful computing there are now many more exciting opportunities. This seminar will begin with a brief review of the early days of holography and the properties of light that make it an important carrier of information. Optical techniques (1D, 2D and time-resolved) that have been developed and become available to mechanical engineers will then be discussed. At the end of the seminar, we will return to the fundamental characteristics of optical systems and show how 3D linear systems theory can help us understand and design new metrology tools in the digital age.
Speaker Introduction: Jeremy Coupland is Professor of Applied Optics and Head of the Optical Engineering Research Group at Loughborough University. He has generated over £5m of research income in 30 projects including 18 as PI and has generated more than 160 publications in this field. In fluid metrology he pioneered holographic particle image velocimetry and gained an NPL Metrology Award in recognition of this work. These techniques have been applied to the study of unsteady flow within IC engines (EPSRC GR/K11147 and GR/K57527). He was a founder member of the International Cavitation Research Institute (funded by Lloyd’s Register Foundation with City University and TU Delft) studying the application of digital holographic microscopy to the study cavitation in bearings. With the Bank of England, he has commercialised sensors for bank note authentication (GB2373324B), instrumentation based on phase Doppler anemometry (GB0428333.9) for precipitation classification and a novel LIDAR system for cloud height/visibility measurement (CS135 with Campbell Scientific Ltd). His interest in surface scattering and the application of coherent methods at the microscale, began after hosting an international workshop on holographic methods and optical tomography in engineering applications in April 2007 (and subsequently editing a special issue of Measurement Science and Technology). Coherent microscopy and analysis methods were studied in 3D (EU FP7 024928-CMAM), and multiple scattering effects in Coherence Scanning Interferometry (CSI) as part of the EPSRC Grand Challenge EP/E001904/1. New methods to characterise and calibrate CSI have been developed with National Physical Laboratory (NPL) and European National Standards Institutes (MetHPM EU EMPIR with NPL, Microparts EU EMRP with PTB Braunschweig). Recent work has included the introduction of new surface measurement instrumentation using Synthetic Aperture Interferometry (EPSRC EP/M020940/1) and new Boundary Source Methods (BSM) for rigorous computation of surface scattering.
