研究課題/領域番号 |
23KJ0553
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研究機関 | 東京大学 |
研究代表者 |
REN GUOQI 東京大学, 工学系研究科, 特別研究員(PD)
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研究期間 (年度) |
2023-04-25 – 2025-03-31
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キーワード | レーザ開発 / レーザ加工 / 微細加工 |
研究実績の概要 |
The aim of this research is to achieve the precision ultrafast micro processing of semiconductors by inventing a new laser system and controlling the dynamic of excited electrons.
The first step is to develop a novel laser system with a wavelength of 1550 nm. In last year, A narrowband erbium-doped fiber laser oscillator (EDFL) was developed. The mode locked EDFL has an average power of 7.2 mW, a pulse duration of 12 ps at a repetition rate of 50.47 MHz. The spectral bandwidth is 0.37 nm, making it a suitable seeder for the development of a high-average-power master oscillator power amplifier (MOPA) fiber laser system taking advantage of the high SPM during amplification to obtain a broad spectrum and yield sub-ps pulses with a clean temporal profile after pulse compression beyond the power amplifier. Furthermore, a quasi-continuous-wave laser was developed to test the amplification. The output power was 38.24 W with a root mean square instability of 0.19% providing an excellent performance under environmental perturbations. Moreover, the laser had a tunable pulse duration from 2 to 5 μs and a constant pulse energy of 190 μJ.
Besides, through investigating the ultrafast dynamic of ultrafast laser-matter interactions, a new processing method was proposed and experimentally demonstrated in transparent dielectrics, which is expected to be used for other materials.
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現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
This research was well conducted as planned in last year. There are mainly two aspects in my research works.
(1) Laser development for novel processing applications: A 200 kHz master oscillator power amplifier erbium-ytterbium-doped fiber laser system was developed. It has a wavelength of 1548.7 nm with a constant pulse energy of 190 μJ providing a tunable pulse duration of 2 to 5 μs. The all-fiber laser system consists of a gain-modulated laser diode used as a seeder, two pre-amplifiers, and a booster amplifier. The output power of the laser system after collimation was 38.24 W, with a root mean square instability of 0.19% providing an excellent performance under environmental perturbations. After synchronization to femtosecond pulses, the obtained μs laser pulses are expected to contribute to novel microprocessing of semiconductors. Besides, a narrowband erbium-doped fiber laser oscillator (EDFL) was developed. The mode locked EDFL has an average power of 7.2 mW, a pulse duration of 12 ps at a repetition rate of 50.47 MHz. The narrow spectral bandwidth of 0.37 nm makes it a suitable seeder for the development of a high-average-power master oscillator power amplifier (MOPA) fiber laser system.
(2) Laser processing: I investigated the ultrafast dynamics of laser-matter interactions, and then proposed a novel method for precision microprocessing without cracks. By using this method, the drilling depth increases more than 3.3 times, and the aspect ratio is improved at least 2.2 times.
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今後の研究の推進方策 |
In this year, the research will be conducted from the following aspects.
(1) Laser development: To continue developing the novel laser system. The main work is to amplify the power of the ultrafast laser by using a pre-amplifier and a main amplifier. After the amplification, a Treacy compressor consisting of two transmission gratings is needed to compress the laser pulse to get pulses with a duration of 1 picosecond or even femtosecond.
(2) Laser processing: To precisely measure the electron density in the plasma filament generated by an ultrafast laser pulse, which is of significance for the transient and selective laser processing.
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次年度使用額が生じた理由 |
I originally planned to purchase acousto-optic modulators and some gain fiber with a large core diameter for the laser development. However, in the experiment, I found that it is better to order them at the final step of the laser development. Therefore, I will use the left budget in next year together with the new granted funding.
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