光学学报, 2011, 31(9): 0900111, 网络出版: 2011-09-01

30 W级第二代钠信标激光器研究

Investigation of 30 W-Class Second-Generation Sodium Beacon Laser
作者单位

1中国科学院理化技术研究所激光物理与技术研究中心, 北京 100190

2中国科学院研究生院, 北京 100049

摘要
采用Nd:YAG 1064与1319 nm激光在非线性晶体LBO中和频,获得了高功率、高光束质量、窄线宽的准连续微秒脉冲钠信标激光。该钠信标激光平均输出功率为33 W,光束质量因子M2 = 1.25,线宽小于0.4 GHz,波长为589 nm,并可精确调控到钠原子D2谱线,稳定性优于±0.3 GHz,重复频率为500 Hz,脉冲宽度约为120 μs。与连续波钠信标激光相比,准连续微秒脉冲钠信标激光提供了门脉冲选通机制,可消除大气瑞利散射干扰和减小钠导引星像斑拉长现象,从而使自适应光学系统能够实现更好的校正效果,被称为第二代纳信标激光。基于此第二代钠信标激光器,在云南1.8 m口径望远镜上进行了外场试验,观测到激光钠导引星。
Abstract
A quasi-continuous wave (QCW) microsecond-pulse sodium beacon laser with high power, high beam quality and narrow linewidth is achieved by sum-frequency generation (SFG) with Nd:YAG 1064 and 1319 nm lasers in a nonlinear crystal of LBO. Under repetition rate of 500 Hz and pulse width of 120 μs, the 589 nm yellow laser which can be precisely tuned to sodium D2 line is obtained with average output power of 33 W, beam quality of M2 = 1.25, linewidth less than 0.4 GHz and wavelength stability better than ±0.3 GHz. Compared with continuous wave (CW) sodium beacon laser, QCW microsecond-pulse sodium beacon laser named as the second-generation sodium beacon laser can provide a gatable pulse format to eliminate the interference of atmospheric Rayleigh scattering and reduce stretching phenomenon of the imaging spot for sodium guide star. By the combination of the QCW laser sodium beacon and the adaptive optics system, the better correction effect and higher-resolution observation images can be achieved. A second-generation sodium beacon laser prototype is developed and the sodium laser guide star is generated and imaged by the 1.8 m telescope in Yunnan Province.
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