【作者】 张连平；

【导师】 李凤琴；

【作者基本信息】 山西大学 ， 光学， 2018， 硕士

【摘要】 随着全固态单频可调谐激光器的迅速发展及光与原子耦合系统的深入研究,900nm波段全固态钛宝石激光器输出的几个中心波长的单频激光分别对应着铯原子的几对跃迁吸收线,近年来在光-原子操控、量子信息存储等研究领域有着重要的应用。而且,其倍频后获得的450nm波段可调谐单频激光也对应于钡离子基态、铯原子高能态等跃迁吸收线,在原子冷却与俘获、量子计算、量子操控等研究课题中也占据着重要的主导作用。这些应用均要求900nm波段的激光输出功率高、光束质量好、频率稳定性好、线宽窄、噪声低,而且重复性较好、抗干扰能力强。为满足这些性能指标,本论文中我们围绕高功率输出的900nm波段钛宝石激光器及连续单频可调谐进行研究,完成了以下工作:1.主要介绍了钛宝石晶体的吸收光谱、荧光光谱特性及其线宽压窄技术,并从实验需求出发,设计了可同时实现压窄激光器线宽及宽范围连续调谐能力的实验装置;2.理论上从四能级速率方程出发,计算了激光振荡阈值及输出功率随激光器泵浦光与振荡光之间的模式匹配关系变化而变化的规律,为降低泵浦阈值功率、提高900nm波段红外激光输出功率和改善其光束质量提供了理论基础。3.实验上设计了结构紧凑、调节灵活的嵌入式六镜环形谐振腔,通过改变嵌入臂的长短可灵活调节激光器的模式匹配状态,获得最大光-光转换效率。在输出功率为15W的532nm全固态单频激光器的泵浦条件下,获得了900nm波段平均输出功率大于2W,波长调谐范围为852~934nm的宽调谐单频激光器,光束质量因子M~2<1.04,三小时内功率稳定性优于±0.7%。4.实验上我们对911nm钛宝石激光器进行了拓展研究,采用7.5mm长的LBO晶体插入钛宝石激光器腔内进行倍频,当注入11.64W单频532nm激光时,获得了功率为1.63W的455.5nm单频蓝光输出,绿光-蓝光转换效率为14%,自由运转三小时功率稳定性约±2.5%,M~2因子分别为Mx~2=1.31、My~2=1.84。更多还原

【Abstract】 With the rapid development of the all-solid-state single frequency laser with the board tunability and the in-depth study of light interacting with atomic,the single frequency lasers with the board tunability in 900 nm wave band are corresponding to a few cesium atomic absorption lines and have important application prospects in optical atomic clocks,cold atom physics,light-atomic manipulation,quantum information storage,and other areas of the research in recent years.And the single frequency blue lasers with the board tunability after the frequency doubling also correspond to a few transition absorption lines such as the barium ion ground state,cesium atomic upper state and so on.The blue laser occupies the important leading role in a few scientific research projects such as the quantum calculation,the preparation of short wavelength entangled light field,the quantum manipulation and so on.These applications require lasers of 900nm band to have high output power,good beam quality,good frequency stability,narrow linewidth,low noise,good repeatability and strong anti-interference ability.In order to satisfy these performance indexes,we have completed the following work to design the Ti:sapphire laser in 900nm wave band for high output power,single-frequency and board tunability in this thesis:1.In this thesis,the physical characteristics,the absorption spectrum,the fluorescence spectrum,the polarization characteristic and the technique of narrowing linewidth of the Ti:sapphire crystal are introduced.For the purpose of the experiment,we design the experiment device what have the technique of narrowing linewidth at the same time the ability of Continuous wide tuning.2.From the four-level rate equations in theory,calculated the threshold pump power and output power varies with the pattern matching relation between pumping laser and oscillation laser.It provides a theoretical basis for the diminution of the threshold pump power,the improvement output power and beam quality in 900 nm band infrared laser.3.In experiment,an embedded ring resonator consisting of six mirrors has been designed.It has a compact structure,stable power and can be like a self-compensation.By changing the distance between two concave mirrors in the embedded structure can be adjusted flexibly the pattern matching relationship between pumping laser and oscillation laser to achieve the best optical to optical conversion efficiency.With the pump power of 15 W all-solid-state laser at 532nm,the average output power more than 2 W in the broad tunable wave range from 852 nm to 934 nm has been obtained.The long-term stability within three hours and the beam quality factor M2 are better than±0.7%and 1.04,respectively.4.The single frequency Ti:sapphire laser in 911 nm expanded research in experiment.A LBO crystal of 7.5 mm long is inserted the intracavity of Ti:sapphire laser for the second harmonic generation.With the pump power of 11.64 W all-solid-state laser at 532nm,output power of 1.63W single-frequency blue light in 455.5nm has been obtained.The green-blue light conversion efficiency is 14%;the long-term stability within three hours is better than±2.5%and the M~2 factors are M_x~2=1.31 and M_y~2=1.84respectively.更多还原