自由曲面干涉检测中的自适应循环补偿结构

Adaptive cyclic compensation structure used in freeform surface interferometric testing

  • 摘要: 为缓解基于可变形镜(DM)的自适应自由曲面干涉仪存在的固有矛盾——不能同时兼顾大动态像差补偿与DM形变监测范围,前期提出了循环利用DM形变量去产生大畸变波前的自适应环形补偿器(ARCC),并得到了初步验证。为了推广其在自由曲面自适应检测中的应用,并结合校正光学系统的自由曲面多为低阶像差面的现实问题,对ARCC的低阶像差补偿特性做出了必要验证和研究。首先,通过Zemax建模对比了ARCC和传统单次往返补偿器(TSRC)对于像散、彗差和球差的补偿能力,得出ARCC补偿像散和彗差的能力近似为TSRC的2倍,补偿球差的能力也要显著大于TSRC,验证了ARCC的低阶像差补偿优势;其次,研究了ARCC的低阶像差类型补偿规律,得出ARCC结构中DM上的像差类型与补偿给被测面的像差类型是“一对多”或“多对一”的关系。结果证明:在实际中分别使用ARCC和TSRC对4块低阶像差自由曲面进行补偿验证,同样的DM形变量下,与传统补偿结构相比ARCC展现出更加出色的低阶像差补偿能力。

     

    Abstract: In order to alleviate the inherent contradiction of existing deformable mirror (DM)-based adaptive freeform surface interferometers, which can not take into account both large departure coverage and DM surface monitoring, therefore, adaptive ring-cavity compensator (ARCC) was proposed, which can generate large departure wavefront using DM deformation multiple times, and it had been preliminarily verified. Considering the practical application of ARCC and the fact that most freeform surfaces in optical systems were low-order aberration surfaces, the low-order aberration compensation characteristics of ARCC were verified and studied. Firstly, the compensation capability of ARCC and TSRC (traditional single round compensator) for astigmatism, coma and spherical aberration was compared by Zemax modeling. It was concluded that the ability of ARCC to compensate astigmatism and coma were about twice that of TSRC, and the ability of ARCC to compensate spherical aberration was also significantly greater than TSRC, which verified the advantage of ARCC in low-order aberration compensation; Secondly, the low-order aberration compensation of ARCC was studied, and it was include that the aberration types on DM in ARCC structure was one-to-many or many-to-one with the aberration types compensated to the tested surface. The results show that in practice, four low-order aberration free-form surfaces are compensated and verified by using ARCC and TSRC respectively. Under the same DM stroke variable, ARCC shows more excellent low-order aberration compensation ability than the TSRC.

     

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