2004 Fiscal Year Final Research Report Summary
Noise induced order : An experimental approach with optical bistable systems
| Project/Area Number |
14340116
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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 |
物性一般(含基礎論)
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| Research Institution | Kobe University |
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Principal Investigator |
KOHMOTO Toshiro Kobe Univ., Faculty of Science, Assit.Professor, 理学部, 助教授 (70192573)
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| Co-Investigator(Kenkyū-buntansha) |
FUKUDA Yukio Kobe Univ., Faculty of Science, Professor, 理学部, 教授 (40025482)
KUNITOMO Masakazu Kobe Univ., Faculty of Science, Professor, 理学部, 教授 (40031348)
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| Project Period (FY) |
2002 – 2004
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| Keywords | stochastic resonance / optical bistability / noise light |
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| Research Abstract |
We studied stochastic resonance (SR) as a typical phenomenon of noise induced order. SR is a cooperative phenomenon that the output signal-to-noise ratio (SNR) is enhanced by adding random noise to the input coherent signal. In spite of its strange appearance, it occurs in various systems. In view of the ability of controlling SNR by adding noise, it is expected to be applied to signal processing, especially to optical signal processing.
1.SR experiments in hybrid optical bistable systems were performed for a sinusoidal input signal. The experimental results show that, with smaller noise correlation time, the peak value of the SNR is larger, the width of the resonance is narrower, and the noise intensity which gives the peak SNR is smaller.
2.SR for a binary input signal was studied by numerical simulations. It was found that the output signal has a gain of information, and that the noise with a small correlation time is favorable for SR and for the gain. The behavior of SR for image data was simulated. The simulation results show that this system can improve the visibility of images and can be a powerful tool for signal processing.
3.A new type of SR by potential fluctuation, where the potential barrier is varied, was studied. The fundamental characteristic of the SR by potential fluctuation was compared with that of the standard type of SR by noise input. Several new features were found in our experiment.
4.All-optical bistable systems to apply SR to optical signal processing were constructed, where a diode laser and Fabry-Perot resonator with a dye solution (ZnPC) or semiconductor crystal (ZnTe) between two mirrors were used. This system can give a fast operation of all-optical SR.
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