2016 Fiscal Year Research-status Report
アキシコンを用いた共振器内コヒーレントビーム結合技術開発と応用
| Project/Area Number |
16K04986
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| Research Institution | Institute for Laser Technology |
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Principal Investigator |
コスロービアン ハイク 公益財団法人レーザー技術総合研究所, レーザーバイオ化学研究チーム, 副主任研究員 (70291036)
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | Corner-cube reflector / CCR resonator / Axicon / passive CBC |
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| Outline of Annual Research Achievements |
In this fiscal year we have studied experimentally and theoretically the basic polarization and reflection properties of corner-cube and axicon retro-reflectors. An experimental apparatus was constructed. Near- and far-field intensity distribution profiles for depolarized, p- and s- polarized outputs of these retro-reflective elements have been obtained and analyzed. In the case of CCR, axial-orientation dependent measurements were performed as well. We have carried-out also case-calculations for several polarization states based on Fresnel equations and compared them with the experiments. The results showed that in the case of the CCR one could in principle obtain linear polarized output, while for the axicon resonator the eigen-modes have only radial and/or tangential polarization.
We have reconstructed the cryogenic cooled Yb:YAG TRAM laser system and made experiments using a conventional mirror with 100 % reflection (Fabry-Perot (FP) resonator) and a corner cube retro-reflector (CCR). The obtained data have been compared. For instance, the slope efficiency in the case of FP and CCR resonators were ~ 50 % and ~ 33 %, respectively. We have monitored also the near-field and far-field patterns of the laser radiation in both cases. Data analysis is now in progress.
A video was taken showing the coherent beam combination (CBC) effect in case of CCR resonator.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Although there was an unexpected event - extensive construction work in the laboratory, we have slightly changed the planning of the research and could use the time effectively. Namely, we purchased the axicon lens with 90 degrees apex angle earlier as planned and could do extensive polarization dependent experiments and study its reflection properties. We have done also extensive calculations. Laser experiments were also performed at the later stage, so in effect, we can state that the project is progressing rather smoothly.
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| Strategy for Future Research Activity |
During this fiscal year we will continue doing both calculations and experiments, this time mainly with the axicon lens resonator. Near- and far-field patterns will be monitored and analyzed. We could test the axicon and CCR not only at cryogenic temperature case, but also at room temperature system.
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| Causes of Carryover |
Due to extensive construction work in the laboratory during the last year, the research plan was somewhat changed. As a result, an instrument planned for purchase during the last fiscal year was not purchased. Instead, an order-made axicon lens was purchased. The large part of the incurred amount is the cost difference of these items.
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| Expenditure Plan for Carryover Budget |
Most probably a Shack-Hartman wave-front sensor and a corner-cube retro-reflector (CCR) with metal coating will be purchased.
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Research Products
(6 results)
