基于Nd:LGGG晶体的1.4μm人眼安全激光器研究

发布时间：2018-07-24 13:18

【摘要】：波长为1.4μm的激光因其在射入眼睛时,房水和晶状体能够吸收较大成分,因而到达视网膜的辐射激光较少,所以对人的眼睛具有安全特性。本文主要介绍了基于新晶体Nd:LGGG作为增益介质,石墨烯作为可饱和吸收体的被动调Q人眼安全激光器及其应用的状况,并研究了1.4μm人眼安全激光器的输出特性。相对于主动调Q人眼安全激光器而言,被动调Q人眼安全激光器具有结构简单、重量较轻、可靠性好等优点。1.本文全面地介绍了固态激光器的发展过程,对调Q的原理与分类进行了介绍,并完成了对1.4μm人眼安全激光器的理论设计和机械设计。2.简略说明了Nd:LGGG晶体的结构,以及晶体的生长方法和热学性质、光谱性质、吸收特性。Nd:LGGG晶体最强吸收峰位于805纳米附近,最大半峰宽度为8.6 nm,因此Nd:LGGG晶体非常有利于做增益介质,且不需要苛刻的控温。3.系统介绍了石墨烯对光的非线性吸收和可饱和吸收机理,以及石墨烯被动调Q的激光特性。调Q脉冲宽度小于石墨烯的饱和弛豫时间,因此石墨烯属于饱和较快的可饱和吸收体。4.采用石墨烯做可饱和吸收体,首次研究了石墨烯被动调Q的Nd:LGGG激光器,获得1.4μm人眼安全激光输出。在注入泵浦光功率14.3 W时,获得平均功率为255 m W、脉冲宽度为490 ns的1.4μm调Q激光输出,激光最大单脉冲能量为3.2mJ,脉冲峰值功率6.53 W。5.主要创新点:首次以Nd:LGGG作为激光增益介质,石墨烯为可饱和吸收体,实现了波长为1.4μm的激光脉冲,获得的激光脉冲的宽度为490纳秒。
[Abstract]:The wavelength 1.4 渭 m laser is safe for human eyes because the aqueous humor and lens can absorb larger components when it is injected into the eye, so there is less radiation to the retina. This paper mainly introduces the passive Q-switched human eye safe laser based on the new crystal Nd:LGGG as gain medium and graphene as saturable absorber, and its application, and studies the output characteristics of 1.4 渭 m human eye safe laser. Compared with the active Q-switched human eye safety laser, the passive Q-switched human eye safety laser has the advantages of simple structure, light weight and good reliability. In this paper, the development process of solid-state laser is introduced, the principle and classification of Q-switching are introduced, and the theoretical design and mechanical design of 1.4 渭 m human eye safe laser are completed. In this paper, the structure of Nd:LGGG crystal, the growth method, thermal properties, spectral properties and absorption characteristics of Nd:LGGG crystal are briefly described. The strongest absorption peak of ND: LGGG crystal is located near 805 nm, and the maximum half peak width is 8.6 nm. Therefore, Nd:LGGG crystal is very advantageous to be used as gain medium. And does not require harsh temperature control. The mechanism of nonlinear absorption and saturable absorption of graphene and the laser characteristics of passively Q-switched graphene are introduced systematically. The width of Q-switched pulse is smaller than the saturation relaxation time of graphene, so graphene belongs to the saturable absorber. 4. Using graphene as saturable absorber, the Nd:LGGG laser with passively Q-switched graphene has been studied for the first time, and the 1.4 渭 m human eye safe laser output has been obtained. A 1.4 渭 m Q-switched laser with an average power of 255 MW and a pulse width of 490 ns was obtained at a power of 14.3 W. The maximum single pulse energy of the laser is 3.2 MJ and the peak power of the pulse is 6.53 W. 5. The main innovation points are as follows: for the first time, Nd:LGGG is used as gain medium and graphene as saturable absorber. The laser pulse with wavelength of 1.4 渭 m is realized, and the width of the laser pulse is 490nanosecond.
【学位授予单位】：山东师范大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN248

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