{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T20:09:41Z","timestamp":1788552581011,"version":"build-2803163510"},"reference-count":31,"publisher":"Optica Publishing Group","issue":"7","license":[{"start":{"date-parts":[[2025,2,21]],"date-time":"2025-02-21T00:00:00Z","timestamp":1740096000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/doi.org\/10.1364\/OA_License_v2#VOR"},{"start":{"date-parts":[[2025,2,21]],"date-time":"2025-02-21T00:00:00Z","timestamp":1740096000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/opg.optica.org\/policies\/opg-tdm-policy.json"}],"funder":[{"name":"Young Elite Scientists Sponsorship Program by CAST","award":["2022QNRC001"],"award-info":[{"award-number":["2022QNRC001"]}]},{"DOI":"10.13039\/501100012165","name":"Key Technologies Research and Development Program","doi-asserted-by":"publisher","award":["2021YFB3601401"],"award-info":[{"award-number":["2021YFB3601401"]}],"id":[{"id":"10.13039\/501100012165","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":[[2025,3,1]]},"abstract":"<jats:p>\n                    Freeform optics has emerged as a significant design tool over the past decade. Non-rotationally symmetric optical surfaces enable high-performance imaging systems to achieve a large field of view (FOV), high resolution, low distortion, lightweight construction, and compact structure simultaneously. Advances in single-point diamond-turning fabrication and computer-generated hologram (CGH)-based metrology are gradually making optical imaging with freeform optics more practical. In this paper, we present the development and verification of an unobscured off-axis three-mirror freeform aluminum imaging telescope (FAIT). The design, fabrication, metrology, and assembly processes of the FAIT are discussed in detail. This system achieves an unobscured FOV of 4\n                    <jats:sup>\u2218<\/jats:sup>\n                    \u00d74\n                    <jats:sup>\u2218<\/jats:sup>\n                    with a maximum distortion of less than 1%. The optical modulation transfer function (MTF) across the full FOV exceeds 0.7 at the Nyquist spatial frequency of 90\u00a0lp\/mm within the wavelength range of 400\u2013900\u00a0nm. By integrating aluminum freeform reflectors with mechanical and electronic systems, the final FAIT successfully captures high-resolution photographs both on the ground and in near-Earth orbit. The all-freeform mirrors ensure that the FAIT maintains a compact envelope. Furthermore, the all-aluminum optomechanical structure facilitates effective athermalization while preserving cost-effectiveness and lightweight characteristics. Additionally, its weight of approximately 2.9\u00a0kg renders the entire FAIT system highly advantageous for space applications.\n                  <\/jats:p>","DOI":"10.1364\/ao.554593","type":"journal-article","created":{"date-parts":[[2025,1,28]],"date-time":"2025-01-28T14:00:52Z","timestamp":1738072852000},"page":"1677","update-policy":"https:\/\/doi.org\/10.1364\/crossmark_policy","source":"Crossref","is-referenced-by-count":7,"title":["Unobscured off-axis three-mirror freeform all-aluminum imaging telescope"],"prefix":"10.1364","volume":"64","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4773-5402","authenticated-orcid":true,"given":"Jiadong","family":"Yu","sequence":"first","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"}]},{"given":"Rong","family":"Gao","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0444j5556","id-type":"ROR","asserted-by":"publisher"}]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jinpeng","family":"Li","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0444j5556","id-type":"ROR","asserted-by":"publisher"}]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peng","family":"Wang","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0444j5556","id-type":"ROR","asserted-by":"publisher"}]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhichen","family":"Xu","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0444j5556","id-type":"ROR","asserted-by":"publisher"}]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ying","family":"Yuan","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0444j5556","id-type":"ROR","asserted-by":"publisher"}]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fengbiao","family":"Wang","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/0444j5556","id-type":"ROR","asserted-by":"publisher"}]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"285","published-online":{"date-parts":[[2025,2,21]]},"reference":[{"key":"ao-64-7-1677-R1","doi-asserted-by":"publisher","first-page":"6450","DOI":"10.1364\/OE.454788","volume":"30","author":"Falaggis","year":"2022","journal-title":"Opt. 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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"}]}}