LD泵浦全固态Yb:YAG陶瓷激光器研究

发布时间：2018-12-25 09:06

【摘要】：近红外波段的激光在科研、工业加工、军事以及医学等领域都有着巨大的应用潜力,全固态激光器更因为其良好的稳定性、紧凑的结构等优势备受人们关注,一直都是人们探索研究的重点。激光透明陶瓷的诞生,具备着很多晶体卓越的性能,所以陶瓷激光器成为近些年众多科学家研究的热点,为固体激光材料向大尺寸以及多功能发展开拓了全新的领域。基于以上的研究背景,本论文研究了国产的各种规格Yb:YAG激光透明陶瓷的激光性质,并在本文中做了详细的报道,本论文的工作主要包括以下几个方面:一、使用中心波长在970 nm的LD作为泵浦源,研究了通光截面积为5 mm*5 mm,通光长度为3 mm和6 mm,Yb3+掺杂浓度为别1 at.%、2 at.%、5 at.%、10 at.%、15 at.%、20 at.%的国产Yb:YAG透明陶瓷的连续激光输出以及波长连续调谐性质。利用通光长度为3 mm、掺杂浓度为15at.%的Yb:YAG透明陶瓷,当吸收泵浦功率为6.3 W时,在透射率为10%的耦合输出镜下得到了2.4 W的连续激光输出,其斜效率为47%;利用通光长度为6 mm、掺杂浓度为10 at.%的Yb:YAG透明陶瓷,当吸收泵浦功率为6.6 W时,在透射率为10%的耦合输出镜下得到了2 W的连续激光输出,其斜效率为41%。然后在谐振腔的输出端插入三棱镜实现波长连续调谐输出,利用通光长度为3mm、掺杂浓度为15 at.%Yb:YAG透明陶瓷,吸收7W的泵浦功率时,在透射率为0.8%的耦合输出镜下波长连续调谐的范围1017-1096 nm;利用通光长度为6 mm、掺杂浓度为10 at.%Yb:YAG透明陶瓷,在7 W的泵浦功率时,在透射率为0.8%的耦合输出镜下波长连续调谐的范围1034-1096 nm。第二、利用Lab VIEW软件编程校正激光诱导击穿光谱(LIBS)技术测量的光谱背景噪声。在本实验中利用调Q脉冲固体激光器,脉宽为10 ns,输出的中心波长为1064 nm,可以输出的最大激光能量为150 m J,然后对输出的1064 nm的脉冲激光经过三倍频至355 nm,然后聚焦到样品表面,最后利用光谱仪采集LIBS光谱。但是因为LIBS光谱中存在较强连续背景光,在此工作中,我们根据LIBS技术所测得的光谱数据的特点,先找到所测得的全光谱范围内的所有极小值,然后利用一个合适的阈值,去除这些极小值中不合理的极小值,最后利用一项或者多项多项式来拟合这些剩余的极小点,最后用拟合的曲线近似代替全光谱范围的连续背光进行光谱校正。之后利用Lab VIEW对此算法进行编程,使得该程序可以实现自动估算校正激光诱导击穿光谱技术所测得的光谱数据中的连续背光,得到更为合理的光谱图,最终实现不用过多的人为干预,便可以灵活的根据所得测的光谱,校正光谱中的连续背光,得到更为合理的光谱图。该方法不仅适用于LIBS技术光谱的连续背光的校正,同样适用于其它类型光谱的连续背光校正。
[Abstract]:Near-infrared lasers have great application potential in scientific research, industrial processing, military and medical fields. All solid-state lasers have attracted much attention because of their good stability and compact structure. It has always been the focus of people's exploration and research. The emergence of laser transparent ceramics has a lot of excellent crystal properties, so ceramic lasers have become a hot spot of many scientists in recent years, which has opened up a new field for the development of solid-state laser materials to large size and multi-function. Based on the above research background, the laser properties of various kinds of Yb:YAG laser transparent ceramics made in China have been studied in this paper, and detailed reports have been made in this paper. The work of this thesis mainly includes the following aspects: 1. Using LD with a central wavelength of 970 nm as the pump source, the optical cross section area of 5 mm*5 mm, and the doped concentration of 6 mm,Yb3 with 3 mm were studied. Continuous laser output and wavelength tunable properties of 20 at.% Yb:YAG transparent ceramics. Using the transparent Yb:YAG ceramics doped with 3 mm, at a concentration of 15at.%, the CW laser output of 2.4W is obtained under the coupling output mirror of 10% transmittance when the absorption pump power is 6.3W. Its oblique efficiency is 47. Using transparent Yb:YAG ceramics doped with 6 mm, in length and 10 at.% in concentration, when the pump power is 6.6 W, the continuous laser output of 2 W is obtained under the coupling output mirror with 10% transmittance, and the oblique efficiency is 41%. Then a prism is inserted into the output end of the resonator to realize the continuous wavelength tuning output. When the pass length is 3mm and the doping concentration is 15 at.%Yb:YAG transparent ceramics, the pump power of 7W is absorbed. Wavelength continuous tuning range 1017-1096 nm; under a coupled-output mirror with a transmittance of 0.8% Using transparent ceramics doped with 6 mm, in length and 10 at.%Yb:YAG at 7 W pump power, the wavelength tuning range of 1034-1096 nm. under a coupling output mirror with a transmittance of 0.8% is obtained. Secondly, the spectral background noise measured by laser induced breakdown spectroscopy (LIBS) is corrected by Lab VIEW software. In this experiment, Q-switched pulsed solid-state laser is used. The center wavelength of 10 ns, pulse width output is 1064 nm, and the maximum energy is 150mJ. Then, the output pulse laser of 1064 nm passes through three times frequency to 355 nm,. Then focus on the surface of the sample, and finally collect the LIBS spectrum by spectrometer. But because there is a strong continuous background light in the LIBS spectrum, in this work, according to the characteristics of the spectral data measured by the LIBS technique, we first find all the minimum values in the whole spectral range, and then use an appropriate threshold. The unreasonable minimum of these minimums is removed, and the residual minimum points are fitted by one term or polynomial, and the spectral correction is carried out by using the fitted curve approximation instead of the continuous backlight in the whole spectral range. After that, the algorithm is programmed by Lab VIEW, which can automatically estimate and correct the continuous backlight in the spectral data measured by laser induced breakdown spectroscopy, and get more reasonable spectra. Finally, without too much human intervention, we can flexibly correct the continuous backlight in the spectrum according to the measured spectrum, and get a more reasonable spectral map. This method is not only suitable for the correction of the continuous backlight in the LIBS spectrum, but also for the continuous backlight correction of other kinds of spectra.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN248

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