| 研究課題/領域番号 |
21K04934
|
|---|
| 研究機関 | 公益財団法人レーザー技術総合研究所 |
|---|
研究代表者 |
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)
|
|---|
| 研究期間 (年度) |
2021-04-01 – 2024-03-31
|
| キーワード | SBS; / ns pulse compression; / compact SBS cell; |
|---|
| 研究実績の概要 |
A variable-length, compact stimulated Brillouin scattering (SBS) amplifier cell was designed. An SBS pulse compressor system was built and tested. FC-72 fluorocarbon liquid was used as an SBS material. A ns Ti:Sapphire laser operating at 15 Hz was employed.
The pulse FWHM before entering the SBS system was 18 ns. With increasing effective length of the SBS cell from 1 to 2 meters (2 - 4 passes) the pulses were compressed from 18 to 8.7 ns. However, the energy conversion efficiency was decreased from 55 % to 30 %. Similar results were obtained also at 780 nm and 820 nm.
The main reason for decreasing conversion efficiency could be the short coherence length of the pump pulses. To increase the efficiency of the SBS pulse compression, pulses with longer coherence length should be used.
|
| 現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
There are several SBS liquids with parameters close to those required for our experiments. The best liquids are FC-40 or FC-70, which have similar characteristics as FC-72 used in present experiments with one exception: their phonon lifetimes are about 0.2 ns or smaller (FC-72 has 1.2 ns phonon lifetime). This roughly means that the pulse compression could be six times or more effective. Unfortunately, due to the supply chain disruption problems, more that 6 months we cannot purchase these SBS liquids.
|
| 今後の研究の推進方策 |
In our forthcoming experiments we will reduce the linewidth of the pulses by employing a bandwidth etalon inside the Ti:Sapphire laser resonator. In this way we will increase the coherence length of the pulses and improve both the pulse compression factor and the energy conversion efficiency.
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.
|
| 次年度使用額が生じた理由 |
We could not purchase SBS liquids (FC-40, FC-70) during the past fiscal year due to the worldwide supply problems. These liquids are used also in semiconductor industry.
We hope to purchase these SBS liquids during this fiscal year and conduct research as originally planned.
|
