2014 Fiscal Year Research-status Report
Development of crystalline mirrors for high precision measurements of space and time
| Project/Area Number |
26610073
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| Research Institution | National Astronomical Observatory of Japan |
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Principal Investigator |
フラミニオ ラファエレ 国立天文台, 重力波プロジェクト推進室, 特任教授 (10723108)
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| Project Period (FY) |
2014-04-01 – 2016-03-31
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| Keywords | Coatings / Crystals / Absorption / Scattering |
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| Outline of Annual Research Achievements |
As originally planned we investigated different solutions to develop low losses mirrors based on crystalline coatings. The following materials were considered: AlAs/GaAs grown on GaAs wafers, AlP/GaP grown on Silicon wafers and GaN/AllInN grown on sapphire. In the end we decided to develop AlAs/GaAs.
A meeting to discuss the plan for the coatings growth and characterization was held at the Laboratoire des Materiaux Avances in Lyon (France). We decided to skip the development of monolayers and to move directly to the development of multilayers made of AlAs/GaAs. To this purpose we purchases a set of GaAs wafers.
Two multilayer coatings were grown on GaAs wafers at Laboratoire de Photonique et de Nanostructures in Paris (France). They were characterized both in term of optical absorption and optical scattering. The results are promising even if some point defects have been detected and are being investigated. For the optical characterization we collaborated with the Laboratoire des Materiaux Avances in Lyon as originally planned.
To prepare the second step which is the transfer of the crystalline coatings on the final substrate we also started to study a possible bonding at room temperature with the Department of Engineering of the University of Tokyo.
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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
No special reasons, just progressing as best as possible given the constraints and the results.
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| Strategy for Future Research Activity |
The plan for the second year consists in transferring the coatings developed during the first year on the final substrates in silica and/or sapphire. The substrate in silica were already purchased during the first year using another budget. The substrates in sapphire will be bought during the second year. The final components will be characterized in terms of optical absorption and scattering.
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| Causes of Carryover |
The initial plan was to have the growth of the coating on the GaAs wafers and their transfer on the final substrates (silica and sapphires) done by the same company in Japan. It finally turned out that the overall cost was too large compared to the allocated budget. We thus changed our plan and separated the process into two different steps: the growth of the coating on the wafers and the transfer to the final substrate. The first step was done at a minimal cost thanks to a collaboration with the Laboratoire de Photonique et de Nanostructures in Paris (France). Some funds allocated for the first year were thus carried over to the second year to accomplish the second step.
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| Expenditure Plan for Carryover Budget |
The plan is to use these funds to pay some of the costs required to transfer the coatings on the silica and sapphire substrates.
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