2022 Fiscal Year Research-status Report
Investigations of spectrally tunable, nanosecond laser pulse compression characteristics by SBS technique
| Project/Area Number |
21K04934
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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, レーザープロセス研究チーム, 副主任研究員 (70291036)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | SBS / ns pulse compression / compact SBS cell |
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| Outline of Annual Research Achievements |
We reduced the linewidth of the pulses by employing an etalon inside the laser resonator. In this way, we strived to increase the coherence length of the pulses and improve the pulse compression factor and the energy conversion efficiency. We successfully performed wavelength-dependent pulse compression measurements for two SBS liquids (FC72 and FC40) and several geometries with different interaction lengths.
Due to the shorter phonon lifetime (0.2 ns vs. 1.2 ns), the compressed pulse FWHM in FC40 was more efficient than in FC72. The SBS energy conversion efficiency was still low, ~ 0.6 (~ 0.7, if 20 % optical losses of the system are taken into consideration). Our analysis showed that the main reason for this is still the short coherence length of the pump pulses (2 cm or 15 GHz).
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
Although I ordered an SHG crystal and a dichroic mirror several months ago with a goal to generate the second-harmonics of the compressed pulses, it arrived just a week ago. So, the experiments planned for the last year will be shifted to this year.
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| Strategy for Future Research Activity |
In our forthcoming experiments we will try to further reduce the linewidth of the pulses.
We will also use another Ti:Sapphire laser with shorter ns pulses.
We will construct a second harmonics generation (SHG) unit and characterize the frequency doubling properties of the SBS compressed pulses.
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| Causes of Carryover |
Although the SHG crystal and a dichroic mirror were ordered during the last fiscal year, they arrived only at the end of April, so the required funds were not used and will be used during this fiscal year.
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