全固态短脉冲Nd:CNGS激光特性研究

发布时间：2018-05-13 19:14

本文选题：Nd:CNGS晶体 + 短脉冲　；参考：《山东大学》2017年硕士论文

【摘要】：全固态短脉冲激光器以其结构简单、稳定性好、使用寿命长、光束质量高、效率高、热效应小等优势,在工业、军事、医疗等多个领域都有很重要的应用。全固态脉冲激光器的发展很大程度上得益于固体激光增益介质的探索与拓展。目前使用最广泛的激光增益介质是掺杂激活离子晶体,其中以Nd3+离子掺杂晶体的研究与应用最为广泛,Nd:YAG、Nd:YVO4、Nd:YLF、Nd:YAP等晶体为代表的激光增益介质已有大量的研究和应用。但是近年来,随着各行各业对激光器件的要求越来越高,探索新的激光晶体及其特性就成为人们不断追求的方向和目标。1998年,俄罗斯研究者首次报道并详细分析Ca3NbGa3Si2O14(CNGS)晶体的性能,证明它是一种性能优良的压电晶体。近年来,研究者针对CNGS晶体良好的热学和光学性能,提出此类晶体有望成为一种新型激光晶体的基质材料。本重点实验室郭世义老师课题组通过大量的调研和实验探索,首次获得一系列掺杂浓度不同的Nd:CNGS晶体。在此基础上,我们课题组与郭世义教授课题组展开合作,对Nd:CNGS晶体的力学、热学、光谱及多功能复合特性研究,并提出Nd:CNGS晶体在超短脉冲激光器件领域中存在一定的发展前景。因此,本论文主要工作是在前期Nd:CNGS晶体物理光学性质测试和连续波激光特性研究基础上,开展Nd:CNGS晶体调Q和锁模短脉冲激光器特性研究。主要研究工作包括:Ⅰ对调Q原理进行简单介绍,分析了声光调Q技术的基本理论;采用声光Q开关,实现主动调Q Nd:CNGS晶体脉冲激光输出;通过设置不同重复频率,测量在不同泵浦功率下,相应的平均输出功率和脉冲宽度,计算相应的峰值功率和单脉冲能量。其中,最窄脉冲宽度为13.8 ns,最大单脉冲能量为92.7μJ,最高峰值功率为6.3 kW。Ⅱ简单介绍了 Cr:YAG、V:YAG晶体;以Cr:YAG晶体为可饱和吸收体为例,详细分析了被动调Q的理论;并在实验上得到Cr:YAG和V:YAG被动调Q Nd:CNGS晶体脉冲激光。最终,采用y切Nd:CNGS晶体得到最大平均输出功率为0.59 W、脉宽为22.89 ns、重频为11.7 kHz、最大单脉冲能量为50.43 μJ、最高峰值功率为2.20 kW的脉冲激光。Ⅲ对层状黑磷可饱和吸收镜的制备方法进行简单介绍;采用少层黑磷作为调制元件,实现Nd:CNGS晶体1.3 μm被动调Q激光输出,对应最窄脉宽0.99μs,最大单脉冲能量1.88 μJ。Ⅳ对锁模原理进行了简单分析,提出了抑制锁模中经常出现的调Q锁模趋势的解决方法;采用SESAM为调制元件,得到Nd:CNGS晶体1.0μm皮秒激光输出,最短脉宽1.0 ps、中心波长1065 nm、重频49.2 MHz、最大输出功率115 mW、对应单脉冲能量2.33 nJ和峰值功率2.23 kW。Ⅴ对锁模激光器中的色散补偿进行简单分析;并且对Nd:CNGS晶体皮秒脉冲激光腔内加入色散补偿啁啾镜对腔内的正色散进行补偿,成功将锁模脉宽压缩至759 fs,最大输出功率为133 mW、单脉冲能量和峰值功率为3.1 nJ和4.1 kW。实验结果表明Nd:CNGS晶体对实现飞秒量级的超快激光很有优势。
[Abstract]:All solid-state short pulse laser has the advantages of simple structure, good stability, long service life, high quality of light beam, high efficiency and low thermal effect. It has very important applications in many fields, such as industry, military and medical treatment. The development of all solid state pulse laser is greatly beneficial to the exploration and expansion of solid laser gain medium. The most widely used laser gain medium is the doped activating ion crystal. The research and application of Nd3+ ion doped crystals is the most widely used. The laser gain media, such as Nd:YAG, Nd:YVO4, Nd:YLF and Nd:YAP, have been widely studied and applied. However, in recent years, the demand for laser devices is becoming higher and higher, and new exploration has been made. The laser crystal and its characteristics have become the direction and target of continuous pursuit in.1998 years. Russian researchers first reported and analyzed the performance of Ca3NbGa3Si2O14 (CNGS) crystal for the first time, and proved that it is a kind of piezoelectric crystal with excellent performance. In recent years, researchers have proposed such crystals in view of the good thermal and optical properties of CNGS crystals. As a matrix material for a new type of laser crystal, the research group of Guo Shiyi, the key laboratory, has obtained a series of Nd:CNGS crystals with different doping concentration through a lot of investigation and experimental exploration. On this basis, we cooperate with Professor Guo Shiyi to study the mechanics, heat, spectra and many of the Nd:CNGS crystals. It is suggested that Nd:CNGS crystals have some potential in the field of ultrashort pulse laser devices. Therefore, the main work of this thesis is to study the characteristics of Nd:CNGS crystal Q and mode locked short pulse lasers on the basis of the physical and optical properties of the early Nd:CNGS crystals and the study of the characteristics of the continuous wave laser. The research work includes: I briefly introduce the principle of Q modulation, analyze the basic theory of the sound and light modulation Q technology, and use the acoustooptic Q switch to realize the active modulation of Q Nd:CNGS crystal pulse laser output. By setting different repetition frequencies, the corresponding average output power and pulse width are measured at different pump power, and the corresponding peak power is calculated and the corresponding peak power is calculated. One pulse energy, of which the narrowest pulse width is 13.8 ns, the maximum single pulse energy is 92.7 mu J, the maximum peak power is 6.3 kW. II. The Cr:YAG, V:YAG crystal is briefly introduced. The theory of passive Q is analyzed in detail with Cr:YAG crystal as a saturable absorber, and Cr:YAG and V:YAG passive Q Nd:CNGS crystal pulse laser is obtained experimentally. Finally, the maximum average output power of the Nd:CNGS crystal is 0.59 W, the pulse width is 22.89 ns, the heavy frequency is 11.7 kHz, the maximum single pulse energy is 50.43 u J, the maximum peak power is 2.20 kW, and the preparation method of the layered black phosphorus saturable absorpable mirror is briefly introduced, and N is used as the modulation element to realize N. D:CNGS crystal 1.3 mu m passively modulated Q laser output, corresponding to the narrowest pulse width of 0.99 Mu s, and the maximum single pulse energy 1.88 mu J. IV, a simple analysis of the mode locking principle is carried out. A solution to restrain the tendency of modulating Q mode locked frequently in the mode lock is proposed. The SESAM is used as the modulation element to obtain the 1 mu m picosecond laser output of Nd: CNGS crystal, and the shortest pulse width is 1 ps. The central wavelength is 1065 nm, a heavy frequency 49.2 MHz and a maximum output power of 115 mW. A simple analysis is made for the dispersion compensation in a mode locked laser with a monopulse energy 2.33 nJ and a peak power 2.23 kW. v. And a dispersion compensation chirp is added to the cavity of a picosecond pulse laser to compensate the positive dispersion in the cavity. The maximum output power is 759 FS and the maximum output power is 133 mW. The experimental results of single pulse energy and peak power of 3.1 nJ and 4.1 kW. show that the Nd:CNGS crystal has a great advantage for the realization of the ultrafast laser at the magnitude of the femtosecond.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN248

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