{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T12:01:31Z","timestamp":1789992091341,"version":"4.0.1"},"reference-count":29,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,19]],"date-time":"2026-09-19T00:00:00Z","timestamp":1789776000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Romanian Ministry of Education and Research","award":["30N\/2023"],"award-info":[{"award-number":["30N\/2023"]}]},{"award":["30N\/2023"],"award-info":[{"award-number":["30N\/2023"]}],"id":[{"id":"https:\/\/ror.org\/00dh5gw98","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Optical response is commonly regarded as an intrinsic property of a photonic structure. Here we show that, in curved photonic systems, geometry plays a dual role: the photonic architecture defines the optical-state landscape, whereas the illumination\u2013observation geometry determines which optical states become experimentally accessible. Self-assembled, millimetre-scale, free-standing curved silica opals coupled to spherical water droplets on Teflon or planar mirrors reveal simultaneous access to multiple Bragg diffraction bands, together with distance-controlled spectral redistribution, spatially organized halos, and pseudo-collimated beams under different illumination\u2013observation geometries. Natural illumination further reveals optical responses relevant to biological and biomimetic photonic structures. Key aspects of this optical functionality are transferred to a graded curved photonic heterostructure formed by partial polystyrene infiltration of a curved silica opal, demonstrating that the underlying geometrical principle extends beyond liquid-confined systems. Curved photonic architectures therefore provide an experimental platform for geometry-controlled optical-state accessibility.<\/jats:p>","DOI":"10.3390\/polym18182288","type":"journal-article","created":{"date-parts":[[2026,9,21]],"date-time":"2026-09-21T11:05:53Z","timestamp":1789988753000},"page":"2288","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Geometry as a Selector of Optical States in Curved Photonic Architectures"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7839-1951","authenticated-orcid":false,"given":"Ion","family":"Sandu","sequence":"first","affiliation":[{"name":"Lasers Department, National Institute for Lasers, Plasma and Radiation Physics, 409, Atomistilor Street, Magurele, 077125 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2425-8770","authenticated-orcid":false,"given":"Claudiu Teodor","family":"Fleaca","sequence":"additional","affiliation":[{"name":"Academy of Romanian Scientists (AOSR), Ilfov Street 3, 050044 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3455-5816","authenticated-orcid":false,"given":"Iulia","family":"Antohe","sequence":"additional","affiliation":[{"name":"Lasers Department, National Institute for Lasers, Plasma and Radiation Physics, 409, Atomistilor Street, Magurele, 077125 Bucharest, Romania"},{"name":"Academy of Romanian Scientists (AOSR), Ilfov Street 3, 050044 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9568-9119","authenticated-orcid":false,"given":"Florian","family":"Dumitrache","sequence":"additional","affiliation":[{"name":"Lasers Department, National Institute for Lasers, Plasma and Radiation Physics, 409, Atomistilor Street, Magurele, 077125 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Iuliana","family":"Urzica","sequence":"additional","affiliation":[{"name":"Lasers Department, National Institute for Lasers, Plasma and Radiation Physics, 409, Atomistilor Street, Magurele, 077125 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5252-088X","authenticated-orcid":false,"given":"Iustina","family":"Popescu","sequence":"additional","affiliation":[{"name":"Geological Institute of Romania, 1 Caransebes Street, 012271 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4552-9819","authenticated-orcid":false,"given":"Marius","family":"Dumitru","sequence":"additional","affiliation":[{"name":"Lasers Department, National Institute for Lasers, Plasma and Radiation Physics, 409, Atomistilor Street, Magurele, 077125 Bucharest, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Sandu, I. 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