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Studies On Theories And Experiment In Femtosecond Laser Micromachining

Posted on:2005-10-23Degree:DoctorType:Dissertation
Country:ChinaCandidate:X C NiFull Text:PDF
GTID:1118360122982257Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
In this dissertation, part of theoretical and experimental studies on the application of femtosecond laser in micro-nanomachining field are presented. The main contents in this dissertation are classified as follows.After several different models are deduced, it is realized to describe the process of the interaction of the femtosecond laser with metal, polymer and dielectric materials.To describe femtosecond laser interaction with metal, the Double-Temperature Equation(DTE) was formatted simply. The electron-lattice couple time is determined through the numerical simulation, which is compared with long pulse. And at the same time, the effect of multi-pulse action is studied. For femtosecond laser interaction with polymer materials, the time-space character of laser must be considered. After the model of femtosecond laser transmission in dielectric is described, the process of plasma generation is studied. And the analysis work is carried out by comparing with long pulse case at the same time. 2,From the sharp of the laser pulses, the correlation of the gaussian pulses with the ablation transversal radius is performed: r2=ρ2(lnE0-lnEt), in which the ρis the spatial radius of the pulse when the energy is down to the 1/e times of the peak energy E0, the Et is energy threshold when the ablation occurred, and the r is the ablation radius. The femtosecond laser speckle has been measured with pinhole scan method in this dissertation. The beam propagation model is also introduced. With the model, the electro-optic components can be designed. Then it is possible that the micro-optic components with special parameters are fabricated by femtosecond laser.3,After femtosecond laser optical machining stages and microscope system are tested, the femtosecond laser micromachining system has been set up successfully. And the factors of femtosecond laser that may have effects on the laser beam quality are measured. To obtain much more information of ablation and the locality of focal point, several detector methods are used. At the same time, coherent detector method is presented to determine the locality of focal point in the lognitudinal direction, which is suitable for the wafer materials. 4,The development of the plastic optical fiber(POF), which is particularly to reduce fiber loss and increase the bandwidth, make the POF have the prominent compete ability in short distance and wide bandwidth aspect. Then micro-optic connectors of the POF becomes the hot research item. The interaction mechanism of the femtosecond laser ablation on core materials of POF(PMMA,PC) has been studied in the dissertation. Finally, it is realized that same micro-optic components have been fabricated by using femtosecond laser in the polymer materials. At the same time, some non-linear phenomena have been observed when the femtosecond laser transmitted in the polymer materials, and the corresponding analysises are given.
Keywords/Search Tags:Femtosecond laser pulses, micro-nanomachining, couple time, fluence threshold, incubation effect
PDF Full Text Request
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