Korean Journal of Optics and Photonics (한국광학회지)

Optical Society of Korea (한국광학회)
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Optical Design of an Off-Axial-Field Two-Mirror System with a Displaced Stop and a Secondary Mirror

조리개와 제 2거울이 횡이동된 비축시야 2반사 광학계 설계

  • Nam, Ji-Woo (Department of Laser and Optical Information Engineering, Cheongju University) ;
  • Lee, Jong-Ung (Department of Laser and Optical Information Engineering, Cheongju University)
  • 남지우 (청주대학교 레이저광정보공학과) ;
  • 이종웅 (청주대학교 레이저광정보공학과)
  • Received : 2020.09.14
  • Accepted : 2020.10.12
  • Published : 2020.12.25
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Abstract

By using an off-axial field with an inverse Cassegrain system where the aperture stop is at the secondary mirror, the two-mirror system can be used for a wide-field objective. However, aberration corrections in conventional two-mirror systems are limited because the design parameters are too small. In this study, we present a new improved design of the off-axial-field two-mirror system. The new design has an independently displaced aperture stop and a secondary mirror. The new design parameters yield more improvement in correction for 5th-order coma and astigmatism, and better aberration balancing for the whole off-axial field. The spot sizes of the new design system are reduced to half of those for a conventional reference design, and the improvement effects are shown for the whole field evenly.

조리개가 제 2거울에 있는 inverse Cassegrain 광학계에서 비축시야를 사용하면, 이 2반사경계는 넓은 시야를 가지는 대물광학계로 사용할 수 있다. 하지만 이 전통적인 회전대칭 구조의 반사경계는 설계변수의 수가 너무 적기 때문에 수차보정에 한계가 있다. 이 연구에서는 조리개와 제 2거울을 별도로 횡이동시켜 성능을 개선한 새로운 2반사 광학계를 설계하였다. 새로운 설계변수를 사용하여 5차 코마와 비점수차에 대한 보정이 개선되었으며, 시야 전체에서 보다 좋은 수차균형을 얻을 수 있었다. 새로 설계된 비축시야 2반사경계는 회전대칭 구조의 통상적인 2반사경계와 비교하여 spot의 크기가 1/2 수준으로 줄어들었으며, 개선의 효과가 시야 전체에 고르게 나타나고 있다.

Keywords

Acknowledgement

이 논문은 2019년도 청주대학교 연구장학 지원으로 수행되었습니다.

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