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2003 Fiscal Year Final Research Report Summary

Study on quantum interference effects in cold atoms and Bose-Einstein condensates

Research Project

Project/Area Number 13440125
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field 物理学一般
Research InstitutionKumamoto University

Principal Investigator

MITSUNAGA Masaharu  Kumamoto University, Faculty of Science, Professor, 理学部, 教授 (90332882)

Co-Investigator(Kenkyū-buntansha) YAMASHITA Makoto  NTT Basic Research Laboratories, Research scientist, 研究主任
FUJII Atsuhiro  Kumamoto University, Shock wave and condensed matter research center, Professor, 衝撃・極限環境研究センター, 教授 (30034375)
Project Period (FY) 2001 – 2003
Keywordslaser cooling / quantum interference effect / electromagnetically induced transparency / polarization gradient cooling / two-photon resonance / optical information storage / sublevel coherence / Bose-Einstein condensation
Research Abstract

We have investigated quantum interference effects such as electromagnetically induced transparency (EIT), coherent population trapping (CPT), and optical information storage in A-type three level atomic systems. In particular, laser-cooled Na atoms and Na atomic vapor have been studied extensively. Under bichromatic radiation that satisfy two-photon resonance condition, the atoms are brought into so-called dark states in which no resonance fluorescence is observed, the phenomenon called CPT. Using this effect, we have studied hyperfine-Zeeman spectra of the Na ground state. The observed spectra agree well with theoretical predictions and reflected properties of two-photon resonance. Quenching of fluorescence can also be useful for mapping of spatially inhomogeneous magnetic field. By imaging the fluorescence distribution by a CCD camera, we have succeeded in two-dimensional mapping of magnetic field produced by anti-Helmholtz coils. This method gives high-resolution, real-time imaging … More of the magnetic field distribution. The EIT linewidth can become extremely narrow, much narrower than Doppler or natural linewidth of the gaseous medium. By careful arrangement of experimental setup and using heterodyne detection technique, we have achieved the observation of subkilohertz (440 Hz) linewidth in Na atoms. Simultaneously obtained dispersion, or refractive index, spectra also showed very slow group velocity of this medium. Finally, we have challenged the possibility of optical information storage by using quantum interference effect. The optical information is stored as sublevel coherence and at later time it is retrieved by converting this sublevel coherence into optical coherence. Proof-of-principle experiment of such idea has been successfully demonstrated. By varying the delay time of the data reading time, we were able to obtain the relaxation time of the sublevel coherence, which was measured to be 72 μs. The evaluation of this constant is quite important since this quantity determines the data-storage time of the futuristic "quantum memory" device that should be applied as a register memory in a quantum computer system. Less

  • Research Products

    (15 results)

All Other

All Publications (15 results)

  • [Publications] 光永正治: "量子干渉効果による光情報記録"光学. 32・4. 229-235 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] H.Asahi, K.Motomura, K.Harada, M.Mitsunaga: "Dark-state imaging for two-dimensional mapping of a magnetic field"Opt.Lett.. 28. 1153-1155 (2003)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M.Yamashita, T.Mukai: "Stabilization of the number of Bose-Einstein-condensed atoms in evaporative cooling via three-body loss"Phys.Rev.A. 68. 063601 (2003)

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      「研究成果報告書概要(和文)」より
  • [Publications] A.Fujii, K.Takiyama, H.Haraguchi, K.Miyazaki, M.Tabuki: "Time-resolved photo-luminescence due to STE in T1Br doped with I-ions"J.Luminescence. (to be published). (2004)

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      「研究成果報告書概要(和文)」より
  • [Publications] M.Mitsunaga: "New Principles in Laser Physics (2) : Lasers without inversion"KOGAKU. 30. 538 (2001)

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      「研究成果報告書概要(欧文)」より
  • [Publications] K.Motomura, M.Mitsunaga: "High-resolution spectroscopy of hyperfine Zeeman components of the sodium D1 line by coherent population trapping"J.Opt.Soc.Am.. B19. 2456 (2002)

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      「研究成果報告書概要(欧文)」より
  • [Publications] M.Yamashita, M.Koashi, T.Mukai, M.Mitsunaga, N.Imoto: "Optimization of evaporative cooling towards a large number of Bose-Einstein condensed atoms"Phys.Rev.. A67. 023601 (2003)

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      「研究成果報告書概要(欧文)」より
  • [Publications] M.Mitsunaga: "Optical information storage by quantum interference"KOGAKU. 32. 229 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] H.Asahi, K.Motomura, K.Harada, M.Mitsunaga: "Dark-state imaging for two-dimensional mapping of a magnetic field"Opt.Lett.. 28. 1153 (2003)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Motomura, T.Koshimizu, K.Harada, H.Ueno, M.Mitsunaga: "Subkilohertz linewidths measured by heterodyne-detected coherent population trapping in sodium vapor"Opt.Lett.. 29. (2004)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] K.Motomura, M.Fuchigami, M.Mitsunaga: "High-resolution coherent population trapping in sodium vapor"Conference on Lasers and Electro-optics (CLEO/Pacific Rim) at Makuhari, Chiba. ThG1-3. (2001)

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  • [Publications] M.Yamashita, M.Koashi, T.Mukai, M.Mitsunaga, N.Imoto: "Optimization of evaporative cooling in trapped Bosonic atoms"Conference on Lasers and Electro-optics (CLEO/Pacific Rim) at Makuhari, Chiba. ThG2-4. (2001)

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  • [Publications] Makoto Yamashita, Masato Koashi, Tetsuya Mukai, Masaharu Mitsunaga, Nobuyuki Imoto, Takaaki Mukai: "Condensate growth with large three-body loss"International Conference on Atomic Physics (ICAP) at Massachusetts. I26. (2002)

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      「研究成果報告書概要(欧文)」より
  • [Publications] Makoto Yamashita, Masato Koashi, Tetsuya Mukai, Masaharu Mitsunaga, Nobuyuki Imoto, Takaaki Mukai: "Quantum kinetic analysis of evaporative cooling in the presence of serious three-body loss"International Symposium on Ultra Low Temperature Physics, BEC2, Kanazawa. (2002)

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  • [Publications] Makoto Yamashita, Masato Koashi, Tetsuya Mukai, Masaharu Mitsunaga, Nobuyuki Imoto, Takaaki Mukai: "Condensate growth with large three-body recombination loss"The 5th Laser Cooling Workshop, Awaji Yumebutai. Januaru 7. (2003)

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Published: 2005-04-19  

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