Bi:GaAs可饱和吸收体全固态激光器的激光特性研究

发布时间：2018-03-11 00:26

本文选题：全固态激光器　切入点：可饱和吸收体　出处：《山东大学》2015年硕士论文　论文类型：学位论文

【摘要】：激光二极管泵浦的全固态激光器不仅体积小、结构紧凑、设备简单、价格低廉,而且输出光束质量高、效率高、性能稳定,因此被广泛应用到军工业以及科研等领域。在全固态激光器谐振腔内插入可饱和吸收元件元件,例如Nd:YAG,GaAs以及其他具有可饱和吸收特性的半导体材料,即可实现调Q与锁模效果。可饱和吸收体作为调Q以及锁模元件具有结构紧凑,价格低,简单易操作等优点,这使得可饱和吸收体自诞生以来一直备受关注。近年来砷化镓可饱和吸收体由于其光学非线性而被成功应用到了多种增益介质的全固态激光器当中。其在1064nm波长处的可饱和吸收普遍认为是由于GaAs中的EL2深能级缺陷造成的,而GaAs的双光子吸收与自由载流子吸收在脉冲形成过程中也起到了重要作用。在本文中,为了提高砷化镓的可饱和吸收特性,我们采用了合金的方式,在GaAs当中掺入Bi元素,并对掺Bi砷化镓作为可饱和吸收体的全固态Nd:GGG激光器进行了关于其输出特性的实验研究。论文主要的研究工作如下：在第一章中,简要介绍全固态激光器,调Q技术,锁模技术,以及调Q锁模技术的发展情况,并对调Q、锁模技术原理进行了简单介绍。在第二章中,对GaAs可饱和吸收体在1064nm波段的调Q、锁模原理进行讨论。总结了制取掺Bi砷化镓的三种主要方式,本文采用离子注入方式制取掺Bi砷化镓,并对制取的样品的可饱和吸收特性进行简要分析。在第三章中,对使用掺铋GaAs作为可饱和吸收体调Q的Nd:GGG全固态激光器进行了关于激光输出特性的研究,并与未掺杂的砷化镓调Q的Nd:GGG全固态激光器进行对比。使用掺Bi砷化镓调Q的激光器的平均输出功率更高,峰值功率更大,半峰宽度更窄,这些实验结果表明掺Bi后GaAs可饱和吸收效果更优。在第四章中,对使用掺Bi砷化镓调Q锁模Nd:GGG全固态激光器输出特性进行实验研究,通过研究实验所得结果可以发现,激光器输出的调Q包络稳定,并且调制深度几乎可以达到百分之百。因此,我们相信,掺Bi砷化镓是一种性能良好的可饱和吸收体。在第五章中,对全文内容进行了总结,结合以后成果指出了下一步将要进行的工作。
[Abstract]:The all-solid-state laser pumped by laser diode is not only small in size, compact in structure, simple in equipment and low in price, but also has high output beam quality, high efficiency and stable performance. Therefore, it has been widely used in military industry and scientific research, where saturable absorber elements such as ND: Yago GaAs and other semiconductor materials with saturable absorptivity are inserted into resonators of all-solid-state lasers. The effect of Q-switching and mode-locking can be realized. The saturable absorber has the advantages of compact structure, low price, simple and easy to operate as Q-switched and mode-locking element. In recent years, gallium arsenide saturable absorbers have been successfully used in all-solid-state lasers with various gain media due to their optical nonlinearity. The saturable absorption is generally considered to be due to the deep level defect of EL2 in GaAs. The two-photon absorption and free carrier absorption of GaAs also play an important role in the pulse formation. In this paper, in order to improve the saturable absorption characteristics of gallium arsenide, we have adopted the alloy method of doping Bi elements into GaAs. The output characteristics of all-solid-state Nd:GGG lasers doped with Bi GaAs as saturable absorbers are studied experimentally. The main work of this paper is as follows: in Chapter 1, all-solid-state lasers and Q-switched techniques are briefly introduced. The development of mode-locking technology and Q-switched mode-locking technology is briefly introduced. In chapter two, the principle of Q-switched and mode-locking technology is briefly introduced. The principle of Q-switching and mode-locking of GaAs saturable absorber at 1064nm is discussed. Three main ways of preparing Bi-doped gallium arsenide are summarized. In this paper, Bi-doped gallium arsenide is prepared by ion implantation. In chapter 3, the laser output characteristics of Nd:GGG all-solid-state laser with bismuth doped GaAs as saturable absorber Q-switched are studied. The average output power is higher, the peak power is higher, the width of half peak is narrower, and the average output power is higher, the peak power is larger and the width of half peak is narrower than that of non-doped GaAs Q-switched Nd:GGG all-solid-state laser. These experimental results show that Bi-doped GaAs has better saturable absorption. In Chapter 4th, the output characteristics of Bi-doped gallium arsenide Q-switched mode-locked Nd:GGG all-solid-state laser are experimentally studied. The Q-switched envelope of the laser is stable, and the modulation depth can reach almost 100%. Therefore, we believe that Bi-doped gallium arsenide is a good saturable absorber. In Chapter 5th, the content of this paper is summarized. Combined with the later results, the future work will be pointed out.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN248

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