在天文观测中,瑞利激光导星自适应光学系统可以补偿大气湍流对成像的影响,并且提高天空覆盖率。能够发射一颗合格的瑞利导星成为该技术的前提。为了实现瑞利激光导星在天文观测中的应用,设计了一套瑞利导星发射系统。首先,根据瑞利激光导星自适应系统的基本要求,介绍了激光器的脉冲能量与重复频率的影响;接着,根据湍流理论分析了发射系统的最佳发射口径与大气湍流对导星的光斑大小的影响;然后,根据发射要求利用Zemax软件设计出一套瑞利导星发射系统。该系统最佳的发射口径为260 mm,采样层为10~11km,导星最佳聚焦高度为9.8 km,理想的导星光斑半径为0.45",存在大气湍流情况下导星光斑半径小于1";最后利用Zemax软件对该系统进行公差分析,分析结果表明该系统相对较容易地实现加工与装调。该发射系统满足激光导星自适应系统的要求,实用性高,设计方法普适。
The adaptive optics system with Rayleigh guide star could compensate the image in observational astronomy, and could improve sky coverage. Projecting a suitable Rayleigh guide star is the precondition of adaptive optics with laser guide star. To realize the image compensation in observational astronomy, a laser launched system was designed. All kinds of parameter were analyzed and a suitable method of launching a laser guide star was completed. First, based on the demand of adaptive optics system with Rayleigh guide star, all kinds of parameter of laser box were probed. Next, the laser launched telescope aperture and the guide star spot size were analyzed according to the turbulence theory. Then, the laser launched system was designed by Zemax. The aperture of launching telescope is 260 mm. The optimal altitude of laser beam waist is 9.8km, with Rayleigh guide star at 10-11km. The laser spot size is 0.45″ without turbulence and less than 1″ with turbulence. Finally, the system was analyzed with tolerance by Zemax, and the results demonstrated that the system was easily to process. The laser projected system could suffice the demand of laser guide star adaptive optics and the method to design the system could be widely used.