1990 Fiscal Year Final Research Report Summary
Persistent Hole Burning and Femtosecond Photon Echo Using Diode Laser
| Project/Area Number |
01460045
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
物理学一般
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| Research Institution | University of Tsukuba |
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Principal Investigator |
NAKATSUKA Hiroki Inst. of Appl. Phys. Univ. of Tsukuba Associate Professor, 物理工学系, 助教授 (10111915)
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| Co-Investigator(Kenkyū-buntansha) |
ONARI Seinosuke Inst. of Appl. Phys. Univ. of Tsukuba Professor, 物理工学系, 教授 (70015824)
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| Project Period (FY) |
1989 – 1990
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| Keywords | persistent hole burning / diode laser / photon echo / optical memory / fractal / organic dye / polymer glass / spectral diffusion |
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| Research Abstract |
1. The incoherent light photon echoes by using a cw multi-mode diode laser or a superluminescent diode have been performed for the first time.
2. Persistent hole burning has been attracting much attention because of its potentiality as future multi-wavelength optical memory. We found out an efficient persistent hole burning material HITC/PVA at the wavelength region of conventional diode lasers, near 780 nm.
3. Using the wavelength sweep by changing the injection current into diode lasers, we observed the time evolution of the persistent hole in HITC/PVA with a temporal resolution of 10 msec.
4. We found that the persistent hole in HITC/PVA can be proved more than 1000 times when it was once burnt.
5. By using the methods mentioned above, we observed spectral diffusion and self-refilling process of the persistent hole in HITC/PVA.
6. We observed the temporal evolution of persistent holes in two samples HITC/PVA (polymeric host) and HITC/EtOH (monomeric host), and explained the behavior by assuming that the two level systems in the host are spatially distributed like a fractal. This theory gives the photon echo decay curve, persistent hole shape and the temperature dependence of the hole width which depend on the fractal dimension D. By comparison with the experiment, we obtained D=2.1 2.3 for HITC/PVA and D=2.7 for HITC/EtOH.
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