以雙色飛秒雷射合成波行研究聚甲基丙烯酸甲酯的光熔蝕現象

簡易檢索 / 詳目顯示

回結果列表

研究生：	鄧逵中 Teng, Kuei-Chung
論文名稱：	以雙色飛秒雷射合成波行研究聚甲基丙烯酸甲酯的光熔蝕現象 Femtosecond Laser Ablation of Polymethylmethacrylate (PMMA) via Dual-color Synthesized Waveform
指導教授：	潘犀靈 Pan, Ci-Ling
口試委員:	謝文峰 Wen-Feng Hsieh 李晁逵 Chao-Kuei Lee
學位類別：	碩士 Master
系所名稱：	電機資訊學院 - 光電工程研究所 Institute of Photonics Technologies
論文出版年：	2014
畢業學年度：	102
語文別：	英文
論文頁數：	94
中文關鍵詞：	熔蝕、飛秒
外文關鍵詞：	Ablation, Femtosecond
相關次數：	點閱：68 下載：0
分享至:	分享至facebook 分享至twitter

查詢本校圖書館目錄查詢臺灣博碩士論文知識加值系統勘誤回報

在這篇論文中, 我們研究甲基丙烯酸甲酯(壓克力)之單色與雙色飛秒雷射熔蝕現象。光源是鈦藍寶石雷射產生之基頻()與倍頻(2)光，我們量測樣品上熔蝕之面積並計算熔蝕過程之臨界閾值分別為2.53和1.86焦耳每平方公分；在雙色熔蝕之實驗中，我們設計並架設了一個同軸實驗架構，且著重於熔蝕洞面積對基頻與倍頻光間相對相位之變化，其中，基頻與倍頻光之脈衝在時域與空間上都是重疊的，我們發現，當基頻與倍頻光之偏振態相互平行時，熔蝕洞面積之變化和相對相位有強烈之對應關係，當基頻與倍頻之比例為8%時，我們可觀察到面積調制深度達到31%，此現象可解釋為合成電場波形對熔蝕之多光子吸收效率的影響，此外，我們也發現，當倍頻光相對於基頻光之比例越來越高時，這種調制現象則變的不明顯，而此種現象可解釋為，倍頻2之雙光子吸收激發相對於基頻之三或四光子吸收激發，逐漸主導了熔蝕現象。

In this dissertation, we report the experiment and results of single color and two color femtosecond ablation of Polymethylmethacrylate(PMMA). The ablation threshold of PMMA by fundamental () and second harmonic (2) of a femtosecond Ti:sapphire laser amplifier are 2.53 J/cm2 and 1.86 J/cm2 respectively. For two color ablation, we designed and built an in-line system. We studied the effect of relative phase between the two wavelengths on the ablation hole area. The pulses of two colors are overlapping in both time and spatial domain. When the polarizations of two color are parallel, the ablation hole area depends strongly on the relative phase between the fundamental and second harmonic beams. A modulation depth of (31%) in the ablated area was observed with a 2/ power ratio of 8%. This phenomenon could be explained by the dependence of ablation on multiphoton ionization rate, which is related to the synthesized waveform. We also found that when the 2/ power ratio becomes higher, the modulation depth or contrast of ablated holes becomes unclear. This characteristic could be explained as the two photon-ionization rate of the second harmonic beam of PMMA dominates over that of the fundamental beam which is due to three or four-photon ionization.

中文摘要    I
Abstract    II
Acknowledgements    III
Table of Contents    IV
List of Figures    VI
List of Tables    IX
Chapter 1    Introduction    1
1    History    1
2    Motivation    2
3    Organization of dissertation    3
Chapter 2    Femtosecond laser Ablation for Micro-scale Machining    4
1    Material removal: Pulsed laser ablation    4
2    Material ablation threshold measurement    6
2.1.    General observation    6
2.2.    Simple technique for measurements of pulsed Gaussian-beam spot size    6
3    Incubation effect of Ablation    8
3.1.    Single and multiple pulse fs laser    8
3.2.    Incubation Effect on Wide band gap material    9
3.3.    Description of Exponential and Power Law    10
4    Ablation of wide band gap dielectric    13
4.1.    Multiphoton ionization , avalanche ionization and tunneling ionization    13
4.2.    Model of electron evolution-Fokker Plank equation    15
5    Relative work    17
Chapter 3    Experimental Details    18
1    Characteristic of sample    18
2    The femtosecond laser system and Main Components    21
2.1.    Laser source    21
2.2.    Laser stability and beam quality    24
2.3.    Second harmonic generation BBO    27
2.4.    GVM Compensating BBO    29
2.5.    Reflecting silicon wafer    35
3    Experiment Setup    44
3.1.    Setup for single color ablation at 400nm & 800nm    45
3.2.    Setup of Two color relative phase ablation    46
3.3.    Setup of Two color ablation with variable power ratio.    50
4    Theoretical calculation of relative phase in prism    52
5    Relative phase modulation in air    58
6    Simulation    60
Chapter 4    Femtosecond laser ablation Morphology    63
1    Interference of Second harmonic generation beams    63
2    400nm & 800nm Single color ablation    67
2.1.    Ablation threshold measurement at 400nm    67
2.2.    Ablation threshold measurement of 800nm    69
2.3.    Conclusion and discussion    71
3    400nm & 800nm Two color laser ablation    74
3.1.    Relative phase ablation with different Power ratio    75
3.2.    Hole area versus different Power ratio    81
3.3.    Polarization between two color(Parallel, Perpendicular)    85
3.4.    Two color pulses separated in time domain    88
4    Comparison of Femtosecond and Nanosecond Pulse ablation    93
4.1.    Images of NS and FS pulses    93
Chapter 5    Summary and Conclusions    94
1    Summary and Conclusions    94
2    Future work    96
2.1.    Electronic shutter    96
2.2.    Relative phase modulation in air    96

                                

[1] M. D. F. B.C. Stuart, A. M. Rubenchik, B.W. Shore, M. D. Perry, "Laser-Induced Damage in Dielectrics with Nanosecond to Subpicosecond Pulses," Physical Review Letters, vol. 74, 1994.
[2] D. Ashkenasi, M. Lorenz, R. Stoian, and A. Rosenfeld, "Surface damage threshold and structuring of dielectrics using femtosecond laser pulses: the role of incubation," Applied Surface Science, pp. 101–106, 1999.
[3] J. Z. Sandra Zoppel, Georg A. Reider, "Two color laser ablation: Enhanced yield, improved machining," Applied Surface Science, vol. 253, pp. 7692–7695, 2007.
[4] n. i. m. okoshi, "Laser ablation of polymers using 395 nm and 790 nm femtosecond lasers," Appl. Phys. A, vol. 79, pp. 841–844, 2004.
[5] G. A. R. E. Schwarz, "Laser-induced plasma by two-color excitation," Applied Physics B, 2011.
[6] J. M. D. X. He, R. Rakowski, C. M. Heyl, A. Persson, J. Mauritsson, A. L’Huillier, "Interference effects in two-color high-order harmonic generation," PHYSICAL REVIEW LETTERS A, vol. 82, 2010.
[7] K.-Y. Kim, "Generation of coherent terahertz radiation in ultrafast laser-gas interactions," PHYSICS OF PLASMAS, vol. 16, 2009.
[8] J. H. G. K. Y. Kim, A. J. Taylor, G. Rodriguez, "Terahertz emission from ultrafast ionizing air in symmetry-broken laser fields," Optical Society of America, 2007.
[9] W. L. Min Li, Yi Shi, Peifen Lu, Haifeng Pan, Heping Zeng, "Verification of the physical mechanism of THz generation by dual-color ultrashort laser pulses," Applied Physics Letters, vol. 101, 2012.
[10] C.-M. C. Chan-Shan Yang, Po-Han Chen,Peichen Yu,Ci-Ling Pan, "Broadband terahertz conductivity and optical transmission of indium-tin-oxide (ITO) nanomaterials," Optical Society of America, vol. 21, 2013.
[11] S. B. J. Bonse∗, J. Krüger, W. Kautek, M. Lenzner, "Femtosecond laser ablation of silicon–modification thresholds and morphology," Appl. Phys, A, 2002.
[12] J. B. S. Baudach ), J. Kru¨ger, W. Kautek, "Ultrashort pulse laser ablation of polycarbonate and polymethylmethacrylate," Appled Surface Science, pp. 555–560, 1999.
[13] J. M. Liu, "Simple technique for measurements of pulsed Gaussian-beam spot sizes," OPTICS LETTERS, vol. 7, p. 196, 1981.
[14] J. Bonse, J. M. Wrobel, J. Krüger, and W. Kautek, "Ultrashort-pulse laser ablation of indium phosphide in air," Appl. Phys. A 72, pp. 89–94, 2001.
[15] B. C. Stuart, S. H. M. D. Feit, A. M. Rubenchik, B. W. Shore, and M. D. Perry, "Optical ablation by high-power short-pulse lasers," J. Opt. Soc. Am. B, vol. 13, February 1996.
[16] F. D. Niso, C. Gaudiuso, T. Sibillano, F. P. Mezzapesa, A. Ancona, and P. M. Lugarà, "Influence of the repetition rate and pulse duration on the incubation effect in multiple-shots ultrafast laser ablation of steel," Physics Procedia, pp. 698 – 707, 2013.
[17] s. e. kirkwood, a. c. v. popta, y. y. tsui, and r. fedosejevs, "Single and multiple shot near-infrared femtosecond laser pulse ablation thresholds of copper," Appl. Phys. A 81, pp. 729–735, 2005.
[18] V. M. K.W. Delong, G.I. Stegeman, "Role of color center induced absorption in all-optical switching," Appl. Phys, 1990.
[19] D. L. M. M. Sparks, R. Warren, T. Holstein, A. A. Maradudin, L. J. Sham, E. Loh, Jr., D. F. King, "Theory of electron-avalanche breakdown in solids," PH YSICAL REVIEW B, vol. 24, 1981.
[20] "http://www.lambdaoptics.com/Beta-Barium-Borate-%CE%B2-BaB2O4-BBO.html."
[21] "http://www.castech-us.com/casbbo.htm."
[22] Y. S. Y. T. I. Oh, K. Y. Kim, "Two-dimensional plasma current and optimized terahertz generation in two-color photoionization," Optical Society of America, 2012.
[23] H. B. R. C.W. Carr, S.G. Demos, "Wavelength Dependence of Laser-Induced Damage: Determining the Damage Initiation Mechanisms," PHYSICAL REVIEW LETTERS, vol. 91, 2003.
[24] "http://www.thorlabs.hk/tutorials.cfm?tabID=27503."

全文公開日期本全文未授權公開 (校內網路)
全文公開日期本全文未授權公開 (校外網路)

簡易檢索 / 詳目顯示

相關論文