2002 Fiscal Year Final Research Report Summary
New Principle for Optical Tomography Based on Synthesis and Control of a Three-dimensional Spatial Coherence Function : A Basic Research
| Project/Area Number |
13450029
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Applied optics/Quantum optical engineering
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| Research Institution | The University of Electro-Communications |
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Principal Investigator |
TAKEDA Mitsuo The University of Electro-Communications, Faculty of Electro-Communications, Professor, 電気通信学部, 教授 (00114926)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAMOTO Yoko The University of Electro-Communications, Faculty of Electro-Communications, Research Associate, 電気通信学部, 助手 (50281655)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Coherence / Interferometry / Optical Tomography / Spatial Light Modulator / Profilometry / Optical Metrology |
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| Research Abstract |
The purpose of this research project is to establish the basis of a fundamentally new technique for synthesis and control of spatial coherence function, which enables selective creation of high coherence between a pair of desired points in three-dimensional space. Because the proposed technique uses spatial (rather than temporal) coherence function of a quasi-monochromatic light source, it opens up a new avenue to optical coherence tomography that is completely free from the dispersion problems that are unavoidable in the existing techniques of low-coherence tomography.
The main achievements are summarized as in the following :
1. A theory and a methodology for designing a source distribution that produces a desired distribution of a spatial coherence function in three-dimensional space were established. In particular, a new model of fringe formation was proposed that gives a clear and intuitive picture about the relation between the source shape and the three-dimensional coherence structure.
2. A new principle for the simultaneous sensing of the object distance and the local inclination of the object surface was proposed, and the validity of the principle was verified by experiment.
3. A new scheme of phase-shift technique based on a source shape modulation by means of a spatial light modulator was proposed and verified by experiment. The proposed scheme enables phase shift completely free from a mechanically moving component, such as a piezo-electric transducer or a precision stage.
Integrating all the above results, a new sensing system was developed that successfully demonstrated the shape measurement of three-dimensional structure made of a set of standard gauge blocks.
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