本文選題：飛秒激光 + 周期性結(jié)構(gòu)��； 參考：《山東師范大學(xué)》2015年碩士論文

【摘要】：飛秒激光脈沖由于快、微、強(qiáng)等特點(diǎn)，在細(xì)微加工領(lǐng)域表現(xiàn)出了得天獨(dú)厚的優(yōu)勢(shì)。同時(shí)，飛秒激光與材料的相互作用過(guò)程是一個(gè)非常復(fù)雜的過(guò)程，對(duì)于不同材料，不同的激光能量，飛秒激光與材料作用的機(jī)理不同。本文對(duì)飛秒激光與材料的相互作用過(guò)程進(jìn)行了理論與實(shí)驗(yàn)研究，我們做的具體工作如下： 首先探討了飛秒激光與材料相互作用的過(guò)程與機(jī)理，對(duì)雙溫方程進(jìn)行簡(jiǎn)化，利用fortran軟件進(jìn)行有限元差分計(jì)算，模擬得出了不同入射激光功率密度下金屬銅和鈦的電子和晶格溫度隨時(shí)間的演化規(guī)律，并總結(jié)得出了金屬銅和鈦電子晶格能量耦合時(shí)間隨入射激光功率密度的變化規(guī)律。 其次研究了飛秒激光誘導(dǎo)金屬表面的周期性結(jié)構(gòu)隨入射激光能量的演變情況，當(dāng)入射激光能量較低，在材料的燒蝕閾值附近時(shí)，我們?cè)跓g中心區(qū)域清楚的看到了垂直于入射激光極化方向的周期性表面結(jié)構(gòu)。隨著入射激光能量不斷增加，位于燒蝕區(qū)域中心位置處的周期性條紋結(jié)構(gòu)逐漸被破壞，在燒蝕區(qū)域的外圍區(qū)域周期性條紋結(jié)構(gòu)仍清晰可見(jiàn)，并用周期性結(jié)構(gòu)出現(xiàn)的閾值理論解釋了周期性結(jié)構(gòu)外移出現(xiàn)的原因。在高能量激光入射下，燒蝕區(qū)域周期性表面結(jié)構(gòu)進(jìn)一步被破壞，不再清晰可見(jiàn)，在外圍區(qū)域出現(xiàn)了納米顆粒，但條紋結(jié)構(gòu)的周期并未發(fā)生變化。我們通過(guò)比較實(shí)驗(yàn)測(cè)得的不同入射激光能量下金屬銅和鈦的周期性條紋結(jié)構(gòu)的周期與用公式計(jì)算出的周期比較，理論與實(shí)驗(yàn)符合較好，得出結(jié)論：飛秒激光誘導(dǎo)周期性條紋結(jié)構(gòu)的周期與入射激光能量無(wú)關(guān)，與金屬種類有關(guān)。另外，我們還對(duì)半導(dǎo)體硅材料進(jìn)行了燒蝕分析，發(fā)現(xiàn)了不同于金屬材料的波紋狀周期性結(jié)構(gòu)。我們以鈦為靶材，通過(guò)建立入射激光功率與燒蝕孔徑之間的關(guān)系間接計(jì)算得到鈦的單脈沖燒蝕閾值為0.20J/cm2。同時(shí)我們對(duì)飛秒激光燒蝕硅靶后不同燒蝕區(qū)域進(jìn)行元素成分分析，得出隨著脈沖個(gè)數(shù)的增加，燒蝕區(qū)域的氧含量也隨之增加，對(duì)于相同脈沖個(gè)數(shù)，不同燒蝕區(qū)域的氧含量也不盡相同，燒蝕中心區(qū)域的氧含量要明顯高于邊緣區(qū)域，這對(duì)于以后的飛秒激光精細(xì)加工有著很好的指導(dǎo)作用。 最后我們固定入射激光能量，，對(duì)不同入射激光脈沖個(gè)數(shù)下飛秒激光燒蝕金屬銅和鈦的燒蝕形貌與周期性結(jié)構(gòu)產(chǎn)生的規(guī)律及原因作了簡(jiǎn)要分析，得到了燒蝕孔徑與脈沖個(gè)數(shù)的變化關(guān)系：當(dāng)入射激光脈沖個(gè)數(shù)比較少，燒蝕孔徑隨脈沖個(gè)數(shù)線性增加，當(dāng)入射激光脈沖個(gè)數(shù)增大到400個(gè)時(shí)，燒蝕孔徑隨入射激光脈沖個(gè)數(shù)的影響不大。當(dāng)入射激光的能量密度一定時(shí)，隨著脈沖個(gè)數(shù)的增加，燒蝕區(qū)域的面積在逐漸增加，我們?cè)跓g區(qū)域的邊緣發(fā)現(xiàn)了明顯的周期性結(jié)構(gòu)，并從激光脈沖能量時(shí)空上的高斯分布特征和脈沖能量累積效應(yīng)，討論了脈沖個(gè)數(shù)對(duì)周期性波紋結(jié)構(gòu)產(chǎn)生的影響。
[Abstract]:The femtosecond laser pulse has a unique advantage in the field of fine processing because of its characteristics such as fast, micro and strong. At the same time, the interaction process between femtosecond laser and material is very complicated. For different materials and different laser energy, the mechanism of femtosecond laser interacting with material is different. In this paper, the interaction between femtosecond laser and materials is studied theoretically and experimentally. Firstly, the process and mechanism of femtosecond laser interaction with materials are discussed. The two-temperature equation is simplified, and the finite element difference calculation is carried out by using fortran software. The evolution law of electron and lattice temperature of metal copper and titanium with time under different incident laser power density is obtained, and the variation of energy coupling time of metal copper and titanium electron lattice with incident laser power density is summarized. Secondly, the evolution of periodic structure of metal surface induced by femtosecond laser with incident laser energy is studied. The periodic surface structure perpendicular to the polarized direction of the incident laser is clearly observed in the ablation center. With the increasing of the incident laser energy, the periodic stripe structure at the center of the ablative region is destroyed gradually, and the periodic stripe structure is still visible in the peripheral region of the ablative region. The reason of the outward shift of periodic structure is explained by the threshold theory of periodic structure. The periodic surface structure of the ablative region is further destroyed under the high energy laser incident and is no longer clearly visible. Nanoparticles appear in the peripheral region, but the periodicity of the stripe structure does not change. By comparing the periodicity of the periodic stripe structures of copper and titanium at different incident laser energies measured experimentally with those calculated by the formula, the theoretical and experimental results are in good agreement. It is concluded that the periodicity of periodic stripe induced by femtosecond laser is independent of the energy of incident laser and is related to the type of metal. In addition, we have also analyzed the ablation of semiconductor silicon materials, and found the corrugated periodic structures which are different from metal materials. By establishing the relationship between laser power and ablative aperture, the threshold value of monopulse ablation of titanium is 0.20J / cm ~ 2. At the same time, the element composition analysis of different ablation regions after femtosecond laser ablation of silicon target shows that with the increase of pulse number, the oxygen content of ablation region also increases, for the same number of pulses, The oxygen content in different ablation regions is different, and the oxygen content in the ablation center region is obviously higher than that in the edge region, which has a good guiding effect on the fine processing of femtosecond laser in the future. Finally, at the same time, we fixed the incident laser energy, and briefly analyzed the regularity and reason of the ablation morphology and periodic structure of femtosecond laser ablation of copper and titanium under different number of incident laser pulses. The relationship between ablative aperture and pulse number is obtained. When the number of incident laser pulses is small, the ablative aperture increases linearly with the number of pulses, and when the number of incident laser pulses increases to 400, The ablation aperture has little effect on the number of laser pulses. When the energy density of the incident laser is constant, with the increase of the number of pulses, the area of the ablation region increases gradually, and we find a distinct periodic structure at the edge of the ablation region. The effect of pulse number on periodic ripple structure is discussed based on the characteristics of Gao Si distribution and the effect of pulse energy accumulation on laser pulse energy space-time.
【學(xué)位授予單位】：山東師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN249

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 倪曉昌,王清月;飛秒激光燒蝕研究進(jìn)展[J];激光與光電子學(xué)進(jìn)展;2002年12期

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