陈太喜, 王金鑫, 黄贺, 张斌智, 李鑫, 丘敏艳, 张鑫. 中间像面非理想成像的近红外折反射系统光学装调方法[J]. 红外与激光工程, 2024, 53(5): 20240089. DOI: 10.3788/IRLA20240089
引用本文: 陈太喜, 王金鑫, 黄贺, 张斌智, 李鑫, 丘敏艳, 张鑫. 中间像面非理想成像的近红外折反射系统光学装调方法[J]. 红外与激光工程, 2024, 53(5): 20240089. DOI: 10.3788/IRLA20240089
Chen Taixi, Wang Jinxin, Huang He, Zhang Binzhi, Li Xin, Qiu Minyan, Zhang Xin. Alignment method of intermediate image plane imperfect imaging near-infrared catadioptric system[J]. Infrared and Laser Engineering, 2024, 53(5): 20240089. DOI: 10.3788/IRLA20240089
Citation: Chen Taixi, Wang Jinxin, Huang He, Zhang Binzhi, Li Xin, Qiu Minyan, Zhang Xin. Alignment method of intermediate image plane imperfect imaging near-infrared catadioptric system[J]. Infrared and Laser Engineering, 2024, 53(5): 20240089. DOI: 10.3788/IRLA20240089

中间像面非理想成像的近红外折反射系统光学装调方法

Alignment method of intermediate image plane imperfect imaging near-infrared catadioptric system

  • 摘要: 近年来,基于中间像面非理想成像的近红外折反射系统应用广泛,但由于该波段干涉仪的价格昂贵且难以维护,其应用并不普及,因此在该类系统集成阶段,通常只能采用传统的机械特征定位方式(例如采用中心偏测量仪辅助定位)进行装调。由于传统机械定位方法无法直接借助干涉仪对系统出瞳波像差进行实时高精度监测,即不能通过观察各视场像差变化规律来指导装调,导致系统的装调效率和精度通常难以保证。针对一个口径为150 mm、焦距为450 mm的中间像面非理想成像近红外折反射系统的高精度光学装调方法开展研究,通过对系统中继透镜组透镜薄膜进行包含常用干涉仪工作波长(λ@632.8 nm)的设计,来实现利用可见光激光干涉仪对系统波像差进行高精度检测的目的,然后研究了系统各装调自由度和系统初级波像差的敏感度关系,以失调敏感度单变量分析为基础,分析了各失调维度间的耦合作用特性,在此基础上提出了次镜和中继镜组相互反复迭代联调的光学装调方案。整机装调后,光学系统各视场波前误差(RMS)和设计仿真结果数值大小大致相同,方向一致,均达到成像质量要求。

     

    Abstract:
      Objective  Infrared optical imaging system has excellent environmental adaptability and has been widely used in the field of optical imaging in recent years. In order to make the structure compact, the intermediate image plane formed by the primary and secondary mirror system often retains a large number of primary spherical differences, and the tolerance requirements are strict and the precision of installation is high. At present, the use of infrared interferometer is not popular in scientific research institutions, the commonly used interferometer is visible wavelength interferometer. As a result, the alignment of this kind of optical system often rely on the traditional alignment method that improves the machining accuracy of the mechanical parts and uses the center deviation measuring instrument to assist the positioning, the alignment accuracy cannot be guaranteed. In order to improve the alignment accuracy of this kind of optical system, it is necessary to discuss the alignment method, so that the high-precision alignment of optical system was realized. In this paper, the optical alignment method of a near-infrared refraction catadioptric system with intermediate image plane imperfect imaging of 150 mm aperture and 450 mm focal length was studied.
      Methods  Based on the near-infrared catadioptric optical system correcting lens group lens material does not block the visible waveband. In order to improve alignment accuracy, the lens blooming of correcting lens group was specially designed (Fig.2), the purpose of using the visible laser interferometer to detect the wave aberration of the system with high precision is realized. Based on the univariate analysis of the offset sensitivity, the coupling and aberration characteristics of each offset dimension are analyzed (Fig.4-5). Based on this, the optical setup scheme of the secondary mirror and the relay mirror group is proposed. The process of alignment strategy (Fig.6) is developed and the actual alignment experiment is analyzed.
      Results and Discussions  Experiments show that the center field view wavefront error (RMS) of optical system reaches 0.104λ, F(−1,0) field view RMS is 0.310λ, and F(+1,0) field view RMS is 0.188λ, F(0,−1) field view RMS is 0.216λ, F(0,−1) field view RMS is 0.176λ (Fig.9). When the center field of view is close to diffraction imaging, the edge field of view has serious asymmetry, which is mainly shown as primary astigmatism asymmetry, resulting in poor image quality of the edge field of view (Tab.2). At this time, adjusting the misalignment of the secondary mirror cannot completely eliminate the asymmetry of the edge field of view, so the position of the secondary mirror and correcting mirror group need to be adjusted after several iterations in the process of alignment. After fine alignment of the entire optical system, the center field view RMS reaches 0.114λ, F(−1,0) field view RMS is 0.109λ, and F(+1,0) field view RMS is 0.103λ, F(0,−1) field view RMS is 0.109λ, F(0,−1) field view RMS is 0.110λ (Fig.10), the RMS value of the full field is close to the design value @632.8 nm, achieving the imaging quality requirements
      Conclusions  The optical installation method of the near-infrared refraction and reflection system with non-ideal imaging of the middle image plane is mainly studied. The lens blooming of the near-infrared relay lens group is designed through the laser interferometer application band of 632.8 nm, so that the near-infrared optical system can use the visible laser interferometer for high-precision detection alignment. The alignment of intermediate image plane of imperfect imaging near-infrared catadioptric system was studied. Based on the univariate analysis of offset sensitivity, the coupling characteristics of each offset dimension are analyzed. On this basis, the optical setup scheme of secondary mirror and correcting lens group is proposed. The RMS wavefront errors of each field of view of the optical system after installation and adjustment are roughly the same as the numerical values of the design simulation results, and the direction is the same, both of which meet the requirements of imaging quality. The research results can provide an effective reference for the installation of such near-infrared refraction and reflection optical systems.

     

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