{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T12:27:49Z","timestamp":1785414469594,"version":"3.56.0"},"reference-count":15,"publisher":"Optica Publishing Group","issue":"5","license":[{"start":{"date-parts":[[2025,2,7]],"date-time":"2025-02-07T00:00:00Z","timestamp":1738886400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/doi.org\/10.1364\/OA_License_v2#VOR"},{"start":{"date-parts":[[2025,2,7]],"date-time":"2025-02-07T00:00:00Z","timestamp":1738886400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/opg.optica.org\/policies\/opg-tdm-policy.json"}],"funder":[{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","award":["2021YFB3601401"],"award-info":[{"award-number":["2021YFB3601401"]}],"id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["62105357"],"award-info":[{"award-number":["62105357"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004739","name":"Youth Innovation Promotion Association of the Chinese Academy of Sciences","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100004739","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["opg.optica.org"],"crossmark-restriction":false},"short-container-title":["Appl. Opt."],"published-print":{"date-parts":[[2025,2,10]]},"abstract":"<jats:p>\n                    CubeSats are becoming increasingly popular in scientific missions due to lower costs, but installing a long-focus unobscured reflective optical system within such a small volume is not easy. This paper proposes two methods to increase the focal length of optical systems in cube satellites. One method breaks the planar symmetry of the traditional off-axis three-mirror system, modifying the system structure to be off-axis in two directions, and simultaneously uses a fifth-order\n                    <jats:italic>X<\/jats:italic>\n                    <jats:italic>Y<\/jats:italic>\n                    polynomial freeform surface to correct the higher-order aberrations caused by the off-axis configuration. The other method utilizes convolutional neural networks to restore blurry images generated by high-specification, low-quality systems, while performing optical-digital joint optimization to improve system performance without sacrificing the output image quality. Design examples validate the feasibility of the proposed methods.\n                  <\/jats:p>","DOI":"10.1364\/ao.553713","type":"journal-article","created":{"date-parts":[[2025,1,17]],"date-time":"2025-01-17T09:00:23Z","timestamp":1737104423000},"page":"1278","update-policy":"https:\/\/doi.org\/10.1364\/crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Design of a long-focus unobscured reflective system for CubeSats based on freeform surfaces without planar symmetry and optical-digital joint optimization"],"prefix":"10.1364","volume":"64","author":[{"given":"Junming","family":"Chen","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0444j5556","id-type":"ROR","asserted-by":"publisher"}]},{"name":"University of Chinese Academy of Sciences"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Boyu","family":"Mao","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0444j5556","id-type":"ROR","asserted-by":"publisher"}]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xianglong","family":"Mao","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0444j5556","id-type":"ROR","asserted-by":"publisher"}]},{"name":"University of Chinese Academy of Sciences"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"285","published-online":{"date-parts":[[2025,2,7]]},"reference":[{"key":"ao-64-5-1278-R1","doi-asserted-by":"publisher","first-page":"5063145","DOI":"10.1155\/2019\/5063145","volume":"2019","author":"Villela","year":"2019","journal-title":"Int. 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All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.","name":"copyright","label":"Copyright"}]}}