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All Solid-state Sesam Continuous Wave 1064nm Passively Mode-locked Laser

Posted on:2005-10-13Degree:MasterType:Thesis
Country:ChinaCandidate:J DuFull Text:PDF
GTID:2208360125462435Subject:Optics
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With the development of semiconductor growth technology and band gap engineering, passively mode-locked solid-state lasers achieved by saturable absorber which can generate passive Q-switching, Q-switched mode-locking (QML), and passive mode-locking in dependence on the practical situation, are attractive in applications such as nonlinear frequency conversion, microstructure fabrication and medical applications and have been played an important role in the development of laser technique in the last years. As compared with other mode-locking technologies, passive mode-locking should be more favorable because the saturable absorbers are compact and inexpensive and have fast recovery time and wide spectral range. In addition, one of the significant advantages for passively mode-locked solid-state lasers is the compact and simple cavity configuration. The dissertation presents results of theoretical and experimental researches on the performance of passively mode-locked Nd:YVO4 and Nd:Gd:YVO,, solid-state lasers. The contents can be outlined as follows:1. The history and progress of diode-pumped solid-state lasers are reviewed, and the advantages of them are presented. Various technologies of mode-locking are introduced, and the excellence of passive mode-locking using SESAM and the development of SESAM are highlighted.2. Based on the mode-locking principle and mechanism, the process of passive mode-locking by SESAM is described. And the stability criterion of cw achieving mode-locking derived from rate equations is discussed .3. According to the principle of mode-locking and the performance of SBR, we choose Nd:YVO4 as our laser crystal. Construct our laser cavity corresponding to our theoretical calculation and analysis. 4W of QML average power was achieved corresponding to pump power of 13.5W, and the overall optical-optical efficiency reached 40%, the repetition rate of pulse train are 220MHz ?In the operation of stable cw- mode-locked laser, the pulse duration of are 11.2ps.4. The optical characters of Nd:Gd:YVO4 is introduced and compared with Nd:YVO4 crystal as a new type of effective laser crystal. Stable cw mode-locking pulse train is achieved with the repetition rate of 110MHz and pulse duration of 5.5ps, and cw mode-locking average power of 750mW was achieved corresponding to pump power of 10.2W. As we know, this is the first report on the passively mode-locked Nd:Gd:YVO, laser.5. The structure of a new passive mode-locking device LT-InGaAs is described and its performance of mode-locking is examined. 210MHz mode-locking pulse train is generated under the 120ns Q-switched pulse train, and QML average power of 325mW was achieved corresponding to pump power of 9.35 W for the first time as we know. The reason that we obtain QML rather than cw mode-locking is analyzed and the improvement of the absorber structure is also presented.
Keywords/Search Tags:All-solid-state laser, Diode pumped, mode-locking, QML, Nd:YVO4, Nd:Gd:YVO4, SESAM, SBR, LT-InGaAs
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