本文選題：飛秒激光 + 時空同步聚焦　； 參考：《北京理工大學》2015年碩士論文

【摘要】：飛秒激光是一種應用廣泛的超快激光,飛秒激光具有極短的持續(xù)時間和極高的峰值功率,這使得其在微納加工中具有諸多獨特的優(yōu)勢;時空同步聚焦則是一種全新的寬頻激光光場聚焦方式,時空同步聚焦提供了新的聚焦維度和可控維度,這使得其在光斑尺寸形狀及動態(tài)控制等方面具有突出優(yōu)勢。近年來,越來越多的研究學者將飛秒激光與時空同步聚焦結合并應用于加工領域,這一技術解決了諸多原來單使用飛秒激光加工所具有的諸多問題。例如,避免了長焦距聚焦下飛秒激光加工引起的自聚焦效應;解決了飛秒激光直寫加工微通道截面不圓的問題并實現了具有可變深寬比截面的微通道加工;提高了多光點三維快速成型加工時激光傳播方向精度等。飛秒激光時空同步聚焦加工技術的獨特性質使得其在微通道加工、三維快速成型加工、生物及高散射材料加工、加工過程的高速動態(tài)控制等領域具有巨大的應用前景。然而,飛秒激光時空同步聚焦加工技術是一種非常新的技術,對其特性及加工應用的研究才剛剛開始,尚存在諸多未解決的科學問題。本文對飛秒激光時空同步聚焦的聚焦光斑靜態(tài)及動態(tài)特性進行了理論研究,并且通過實驗研究了其聚焦特性在微納加工中的應用。論文主要研究內容如下:1.通過引入頻率這一光場整形維度,拓展了原空間整形及聚焦的計算算法,研究并實現了通用的空間域和時域超快激光光場整形及聚焦算法。通過理論計算分析了多種振幅整形、相位整形及偏振整形的空間聚焦特性。2.理論研究了時空同步聚焦的光斑的靜態(tài)特性和動態(tài)特性。靜態(tài)上,相比于空間聚焦,時空同步聚焦的光斑的瑞利長度更短,同時時空同步聚焦的焦平面存在一定的傾斜現象;動態(tài)上,時空同步聚焦的聚焦光斑可以隨時間快速位移或變形。根據時空同步聚焦光斑的動態(tài)特性,提出了一種控制超快光斑動態(tài)演化的方法。并將時空同步聚焦技術與其它技術相結合實現了多種形狀光斑的快速移動、光斑間歇式移動、多點同步移動等。這為微納加工提供了全新的控制維度,并為微納加工中超快過程的動態(tài)控制提供了基礎。3.實驗研究了時空同步聚焦光斑的靜態(tài)特性和動態(tài)特性對加工的影響。靜態(tài)上,觀測了時空同步聚焦的空氣電離狀態(tài),并將其與傳統(tǒng)空間聚焦作對比,并將這種聚焦方法應用于微通道加工。動態(tài)上,研究了時空同步聚焦所引起的光斑快速平移現象對加工區(qū)域及加工微結構的影響。
[Abstract]:Femtosecond laser is a widely used ultra-fast laser. Femtosecond laser has a very short duration and a very high peak power, which makes it have many unique advantages in micro-nano machining. Spatio-temporal synchronous focusing is a new mode of wide-band laser field focusing. Spatio-temporal synchronous focusing provides a new dimension of focus and controllable dimension, which makes it have outstanding advantages in the aspects of spot size and dynamic control. In recent years, more and more researchers combine femtosecond laser with spatio-temporal synchronous focusing and apply it to the field of processing. This technique solves many problems of single femtosecond laser processing. For example, the self-focusing effect caused by femtosecond laser processing under long focal length focusing is avoided, and the problem of non-circular microchannel section in femtosecond laser direct-writing processing is solved and the micro-channel machining with variable aspect ratio section is realized. The accuracy of laser propagation direction is improved during the three-dimensional rapid prototyping of multi-light spot. The unique properties of femtosecond laser space-time focusing technology make it have a great application prospect in the fields of micro-channel processing, three-dimensional rapid prototyping, biological and high-scattering materials processing, high-speed dynamic control of processing process, and so on. However, the femtosecond laser spatio-temporal focusing technology is a very new technology. The research on its characteristics and processing applications has just begun, and there are still many unsolved scientific problems. In this paper, the static and dynamic characteristics of the focusing spot of femtosecond laser focusing in time and space are studied theoretically, and the application of the focusing characteristic in micro / nano machining is studied by experiments. The main contents of this paper are as follows: 1: 1. By introducing frequency as the dimension of optical field shaping, the calculation algorithm of original space shaping and focusing is extended, and the general algorithms of spatial and time domain ultra-fast laser field shaping and focusing are studied and implemented. The spatial focusing characteristics of amplitude shaping, phase shaping and polarization shaping are analyzed by theoretical calculation. The static and dynamic characteristics of spatiotemporal synchronous focusing spot are studied theoretically. In the static state, the Rayleigh length of the spot is shorter than that of the spatial focusing, and the focal plane of the spatio-temporal synchronous focusing is inclined to a certain extent. Spatio-temporal focusing spot can shift or deform rapidly with time. According to the dynamic characteristics of space-time synchronous focusing spot, a method to control the dynamic evolution of ultra-fast spot is proposed. The spatio-temporal synchronous focusing technology is combined with other technologies to realize the fast movement of various shapes of light spots, the intermittent movement of light spots, and the synchronous movement of multiple points. This provides a new control dimension for micro / nano machining and provides a basis for dynamic control of ultra fast process in micro / nano machining. The effects of static and dynamic characteristics of spatiotemporal synchronous focusing spot on machining are studied experimentally. In static state, the air ionization state of spatio-temporal synchronous focusing is observed and compared with that of traditional spatial focusing, and this focusing method is applied to microchannel processing. Dynamically, the effect of the fast translation of spot caused by spatio-temporal synchronous focusing on the processing area and microstructure was studied.
【學位授予單位】：北京理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TN249

【參考文獻】

相關期刊論文 前1條

1 陳國夫;程光華;令維軍;;飛秒激光產生與放大技術[J];紅外與激光工程;2008年02期

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本文編號：1843318