【作者】 吴春婷；

【导师】 王月珠；

【作者基本信息】 哈尔滨工业大学 ， 物理电子学， 2007， 硕士

【摘要】 以2μm固体激光器作为发射机的成像雷达、相干多普勒风速监测雷达和大气水分差分吸收雷达是激光雷达研究的重点之一。雷达光源通常要求单纵模、高功率输出。种子激光器(也称为主激光器)提供低功率、窄线宽、单频、稳定的激光输出,从激光器将其放大,获得高功率、窄线宽、单模运行、稳定频率的激光输出。所以实现2μm的注入锁频,为激光雷达提供光源是该课题的主要研究意义。理论上,通过注入锁定的经典理论模型分析了注入锁定理论。实现注入锁频,必须满足主、从激光器的模式匹配;同时对主激光器必须满足一定的注入功率、单频、稳定、窄线宽等。实现注入锁频后,环形腔能量转换效率接近于1,光谱纯度变纯。实验上,首先由于种子光的输出特性直接影响到锁频的实现,所以对种子光进行了若干研究。实验中,采用低温Tm,Ho:YLF微片激光器获得稳定、基横模、单纵模2067nm激光输出,输出功率可达32.8mW。其次着重讨论了种子模与环形腔模式匹配的问题。主从激光器模式匹配与否直接影响锁频的实现及锁频率。对偏角注入和偏轴注入分别进行了研究,实验发现,偏轴注入是影响模式匹配的主要因素。再次,设计了环形功率腔,环形腔仍采用Tm,Ho:YLF晶体作为工作物质,这样易于模式诱导,完成了注入锁频的实验研究。通过实验可以明显地看到注入锁频的实际效果。环形腔单向输出;脉冲建立时间缩短500ns;脉冲宽度变窄,在环形腔输出功率2mJ时,脉宽由未锁定时的219.2ns变为锁定情况下的156.3ns;脉冲输出变稳等,并分析了产生上述现象的原因。在相同的重复频率下,输出脉冲能量随泵浦能量的增加而增加,脉冲宽度随泵浦能量的增加变窄。利用F-P干涉仪慢扫描法,更为直观的看到了注入种子对环形腔的模式诱导作用。更多还原

【Abstract】 The 2-micron laser has particular characters. It is the preferred lamp-house of the imaging LIDAR ,the coherent Doppler LIDAR for wind sensing and the DIAL for measuring change of the depth and the temperature of earthly atmosphere. The lamp-house of LIDAR are always composed of one power oscillator and one seed laser. Seed laser is also called master oscillator. It is provided with low power, narrow linewidth, single frequency, stable laser. Inject seed laser to a power oscillator to obtain high power, narrow linewidth, single-mode, stable frequency laser. In this paper, we use the laser diode pumped Tm,Ho:YLF to achieve injection-locking laser of 2-micron .Theoretically, this paper analyzes the theory of injection-locking. To achieve injection-locking laser, the mode of seed laser and power oscillator must match. The seed laser must be single frequency, stable, narrow linewidth and sufficing some power. Then, analyze the hallmark of spectrum and so on.Experimentally, firstly, in view of the important of seed laser, at low temperature, we achieve perfect seed laser by using Tm,Ho:YLF microchip. The seed laser is stable, single-mode, 2067nm. The output power is up to 32.8mW. Secondly, we research the modes matching. It directly effects the frequency-locked. Both departure from angle and departure from axis can take difficult to the injection-locking. But the latter is more important. Thirdly, we design ring laser to carry out frequency-locked. When inject the seed source into the slaver oscillator through the output coupler, and unidirectional operation can be induced. The time of pulse build-up is shorter. The pulse width is narrower. The output pulse is more stable. Discuss the pulse energy and pulse width change by pump power. Making use of F-P interferometer method, we see more clearly about the mode inducing from seed laser to slaver oscillator.更多还原