| Project/Area Number |
09650038
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | HOKKAIDO UNIVERSITY |
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Principal Investigator |
UOZUMI Jun Research Institute for Electronic Science, Hokkaido University Associate Professor, 電子科学研究所, 助教授 (50184982)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 1998: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1997: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Light scattering / Gaussian speckle / Clustered speckle / Long correlation tail / Fractal speckle / Doubly scattered speckle / Power-law illumination / Power-law intensity correlation / 強度相関 / べき則 / 円環状照明 |
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| Research Abstract |
Recently, random fields with singular properties were found in the framework of Gaussian speckles. The present study aims at analyzing statistical properties and generation conditions of such random fields through theoretical, experimental and simulation approaches.
1. Generating mechanism of structured speckles
Structured speckles (clustered speckles) are found to appear when a diffuser is illuminated by a thin ring-slit aperture. An isotropy of the speckle clustering was shown to be due to circular symmetry of the ring slit. An origin of speckle clustering was shown by means of computer simulations. Developing process of partially-developed clustered speckles are revealed experimentally by using small-roughness diffusers.
2. Axially long spatial correlation
With relation to properties of a non-diffracting beam, it was shown theoretically that the clustered speckles produced by the ring-slit illumination have very long spatial correlations in the axial direction. The results were verified by experiments.
3. Generation of fractal speckles
It was shown experimentally that a double scattering process using a random fractal diffuser and an ordinary diffuser can produce speckle intensity distributions with a fractal property in a Fourier transform plane of the second diffuser. This verified a theoretical prediction given previously. A 3D correlation properties of the speckles were also examined.
4. Fractal speckles in Fresnel and image regions
It was shown that speckle intensity distributions with fractal properties can also be generated in the Fresnel diffraction regions and in the image plane of the ordinary diffuser by using suitable configurations.
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