2006 Fiscal Year Final Research Report Summary
Development of liquid crystal lasers by taking advantage of three-dimensional photonic structure
| Project/Area Number |
17360014
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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 materials science/Crystal engineering
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| Research Institution | RIKEN |
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Principal Investigator |
SHIROTA Koichiro RIKEN, Nanophotonics Laboratory, Senior Research Scientist, 河田ナノフォトニクス研究室, 専任研究員 (00291071)
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| Co-Investigator(Kenkyū-buntansha) |
FUKANO Takashi RIKEN, Laboratory for Cell Function Dynamics, Research Scientist, 細胞機能探索技術開発チーム, 研究員 (80373364)
TAKEYASU Nobuyuki RIKEN, Nanophotonics Laboratory, Contract Researcher, 河田ナノフォトニクス研究室, 協力研究員 (90373323)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Liquid crystal / Photonic crystal / Self-organization / High-performance laser |
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| Research Abstract |
Mirrorless lasing from self-organized soft photonic bandgap materials may be useful for threshold less microlaser. Here, we report on the reduction of a lasing threshold by using three-dimensional photonic structure of blue phase (BP).
In cooling process, a single crystal of BP I grew in the (110) orientation under electric field to become more than 1 cm in diameter. The central wavelength and full width of the photonic band were 592 nm and 10 nm, respectively. The sample was doped with a fluorescent dye, Pyrromethene597, which had a peak emission in the vicinity of the band edge, and excited at 530 nm by a fs-OPA system. Since a fluorescent component of the left-circularly polarization was restrained in photonic bandgap, laser oscillation of the left-circularly polarization occurred at the band edge, 597 nm. The lasing threshold of BP I was found to be half of a chiral nematic phase.
A problem of the blue phase, however, for practical use is its narrow temperature range less than few degrees Celsius just below the clearing point. Appling a polymer stabilization method, we extended temperature range of the blue phase and realized laser oscillation at room temperature. A polymer-stabilized blue phase (PSBP) sample was prepared by UV light irradiation under temperature control to maintain the blue phase. Resultant temperature range of a blue phase was expanded to over 50℃ in width including room temperature. The lasing threshold was found to be approximately half of one-dimensional chiral liquid crystal as well as ordinary blue phase. The use of mono domain sample of PSBP in optical applications seems to hold considerable promise.
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