本文選題：飛秒激光 + 脈沖序列��； 參考：《北京理工大學(xué)》2015年碩士論文

【摘要】：近年來(lái)，基于飛秒激光的微/納制造技術(shù)已經(jīng)成為了科研熱點(diǎn)之一。在傳統(tǒng)飛秒脈沖激光的基礎(chǔ)上發(fā)展而來(lái)的時(shí)域整形的脈沖序列技術(shù)，為實(shí)現(xiàn)材料加工中的高質(zhì)量、高效率、高精度加工提供了可能性。通過設(shè)計(jì)脈沖序列，不僅可以控制固體材料加工中的電子激發(fā)/電離過程，而且甚至可以在飛秒尺度上控制化學(xué)反應(yīng)過程。本人在前人的研究基礎(chǔ)上，結(jié)合飛秒激光控制化學(xué)反應(yīng)過程的原理，從理論和實(shí)驗(yàn)上對(duì)基于脈沖序列設(shè)計(jì)的飛秒激光與物質(zhì)材料的相互作用機(jī)理作出了探索研究。同時(shí)，將時(shí)域整形的雙脈沖用于液相燒蝕制備納米粒子的方法，高效率制備出了小粒徑、均勻分布的硅納米粒子。 本論文主要研究工作和創(chuàng)新點(diǎn)概括如下： （1）采用時(shí)域整形的飛秒雙脈沖在空氣和乙醇環(huán)境中加工半導(dǎo)體和金屬材料。在空氣環(huán)境中，延時(shí)小于1ps雙脈沖加工半導(dǎo)體材料硅和鍺時(shí)，燒蝕面積呈現(xiàn)振蕩減�。欢谝掖辑h(huán)境中，相同實(shí)驗(yàn)條件下，當(dāng)激光通量高于0.4J/cm2時(shí)加工半導(dǎo)體時(shí)，，當(dāng)延時(shí)大于200fs時(shí)會(huì)呈現(xiàn)燒蝕增強(qiáng)的現(xiàn)象。而在使用飛秒雙脈沖加工金屬材料鋁時(shí)，乙醇環(huán)境中的實(shí)驗(yàn)結(jié)果與空氣環(huán)境類似，并沒有存在燒蝕增強(qiáng)的現(xiàn)象。 （2）飛秒激光在電離乙醇分子時(shí)由于乙醇分子中H-O鍵的斷裂會(huì)產(chǎn)生自由電子。泵浦探測(cè)技術(shù)表明，飛秒激光電離乙醇分子這一反應(yīng)完成時(shí)間約200fs，而電子-空穴的結(jié)合往往在半導(dǎo)體材料中更容易發(fā)生。通過時(shí)域整形的脈沖激光，兩束脈沖延時(shí)超200fs后，第二束子脈沖到達(dá)時(shí)由于自由電子密度的升高而對(duì)光子能量的吸收增強(qiáng)，成功的提高了燒蝕效率。同時(shí)，通過設(shè)計(jì)的脈沖序列，還可以有效改善材料的加工質(zhì)量和效率。 （3）使用液相燒蝕方法成功制備出硅納米粒子。傳統(tǒng)飛秒激光在低能量下能夠制備小粒徑的納米粒子，但是制備效率卻降低。本課題通過采用飛秒激光脈沖序列技術(shù)，當(dāng)脈沖延時(shí)超過200fs，與傳統(tǒng)單脈沖激光相比，高效率制備出了小粒徑、均勻分布的硅納米粒子。本方法可以廣泛的加工多種基底材料，實(shí)驗(yàn)過程簡(jiǎn)單易操作。
[Abstract]:In recent years, micro / nano fabrication technology based on femtosecond laser has become one of the hotspots in scientific research. Based on the traditional femtosecond pulse laser, the pulse sequence technology of time domain shaping provides the possibility for the realization of high quality, high efficiency and high precision in material processing. By designing the pulse sequence, not only the electron excitation / ionization process can be controlled, but also the chemical reaction process can be controlled on the femtosecond scale. On the basis of previous studies and the principle of femtosecond laser controlling chemical reaction, the interaction mechanism between femtosecond laser and material based on pulse sequence design is studied theoretically and experimentally. At the same time, the double pulse shaping in time domain was used to prepare nano-particles by liquid phase ablation, and the small particle size and uniform distribution of silicon nanoparticles were prepared with high efficiency. The main research work and innovation of this paper are summarized as follows: Femtosecond pulse shaping in time domain is used to process semiconductors and metal materials in air and ethanol environment. In the air environment, when the delay time is less than 1ps double pulse processing semiconductor materials silicon and germanium, the ablation area decreases, but in ethanol environment, when the laser flux is higher than 0.4J/cm2, the laser flux is higher than that of 0.4J/cm2, while in ethanol environment, when the laser flux is higher than 0.4J/cm2, the ablation area decreases. When the delay is longer than 200fs, it will appear the phenomenon of ablation enhancement. However, the experimental results in ethanol environment are similar to those in air environment, and there is no phenomenon of ablation enhancement when aluminum is processed by femtosecond double pulses. When the femtosecond laser ionizes the ethanol molecule, free electrons will be produced due to the breaking of H-O bond in the ethanol molecule. Pump detection technique shows that the reaction time of femtosecond laser ionization of ethanol molecule is about 200fs, and the combination of electron-hole is more likely to occur in semiconductor materials. With the pulse laser of time domain shaping, after two pulses delay over 200fs, the absorption of photon energy is enhanced due to the increase of free electron density when the second sub-pulse arrives, and the ablation efficiency is improved successfully. At the same time, the quality and efficiency of material processing can be improved effectively by the designed pulse sequence. The silicon nanoparticles were successfully prepared by liquid phase ablation. The traditional femtosecond laser can produce small nanoparticles at low energy, but the preparation efficiency is decreased. By using femtosecond laser pulse sequence technology, when the pulse delay exceeds 200fs, compared with the traditional monopulse laser, the silicon nanoparticles with small particle size and uniform distribution have been prepared with high efficiency. This method can be widely used to process a variety of substrate materials, and the experimental process is simple and easy to operate.
【學(xué)位授予單位】：北京理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN249;TB383.1

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