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DTSTART;TZID=Europe/Moscow:20250717T154000
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DTSTAMP:20260906T021317
CREATED:20250711T065312Z
LAST-MODIFIED:20250711T065312Z
UID:9918-1752766800-1752771600@unam.bilkent.edu.tr
SUMMARY:Engineering light to hop or walk through photonic nanostructures: Fundamental puzzles to sustainable industrial applications
DESCRIPTION:Willem L. Vos\nUniversity of Twente \n\nThe study of the propagation of light through complex composite materials – e.g.\, paint\, foam\, bio-logical tissue – is a topic that has become a field of its own [Nov2012\, Car2021]. This may seem surprising: if a material is so opaque that it scrambles images\, how can one see through? If a laser beam is scram¬bled\, how does optical interference survive? The answer is in essence that interferences survive even millions of scattering events\, observable as speckle or enhanced back scattering. Know-how of light scattering serves to address challenges in high-tech industry – from lighting\, CMOS metrology\, to atmospheric sensing – for sustainable technology\, see Fig. 1 [FFSO].\n \nFigure 1. Schematic illustrating how the joint engineering of broadband light waves by nanostructure and wavefront shaping optimizes light on a target\, for sustainable high-tech appli¬cations. \nThree complementary tools are crucial to control light interference in complex materials: nanostructure\, shape (freeform)\, wavefront shaping. (1) Much progress is made to realize nanostructures: periodic [Goo2023]\, cav¬ity superlattices [Adh2024]\, or chiral [Ota2019]. The chal-lenge to get calibrated densities is met by using in situ X-ray imaging. Since X-ray methods are non-destructive\, devices are available for further study or integration [Sch2024]. (2) External sample shape\, long neglected\, is remarkably crucial\, as known in industry\, and now also in wavefront shaping [Rat2023a]. (3) Wavefronts shaped with SLMs offer many control parameters to meet a desi¬red goal like a highly optimized focus (Fig. 1). This is used to send light deep into a forbidden gap [Upp2021]\, or do secure optical communication [Rat2023b]. A new topic is mutual scattering where extinction (shadow) is control¬led to make objects more transparent or darker\, or sense particle displacement in opaque materials [Rat2024\, Tru2022]. \nFinally\, even the transport of light intensity without interference – at the basis of most scattering optics – still holds puzzles\, notably when well-known models like diffusion break down [Akd2024]. \n  \n[Akd2024] O. Akdemir\, M. D. Truong\, A. Rates\, A. Lagendijk & WLV\, Phys. Rev. A 110 (2024) 033520\n[Car2021] R. Carminati & J. Schotland\, Principles of scattering and transport of light (Cambridge\, 2021)\n[FFSO] See www.freeformscatteringoptics.com; research program of 3 TUs and 6 hi-tech companies\n[Goo2023] M.J. Goodwin\, C.A.M. Harteveld\, M.J. de Boer\, et al.\, Nanotechnology 34 (2023) 225301\n[Koz2022] M. Kozoň\, A. Lagendijk\, et al.\, Phys. Rev. Lett. 129 (2022) 176401; Opt. Express (2023)\n[Nov2012] L. Novotny & B. Hecht\, Principles of Nano-optics (Cambridge\, 2012)\n[Ota2019] Y. Ota\, F. Liu\, R. Katsumi\, et al.\, Y. Arakawa & S. Iwamoto\, Optica 6 (2019) 786\n[Rat2023a] A. Rates\, A. Lagendijk\, A. J. L. Adam\, W. L. Ijzerman & WLV\, Opt. Express 31 (2023) 43351\n[Rat2023b] A. Rates\, J. Vrehen\, L. Mulder\, W. L. Ijzerman & WLV\, Opt. Express 31 (2023) 23897\n[Rat2024] A. Rates\, A. Lagendijk\, M. D. Truong & WLV\, Phys. Rev. A 110 (2024) 063518\n[Sch2024] A. S. Schulz\, M. Kozoň\, G. J. Vancso\, J. Huskens & WLV\, J. Phys. Chem. C 128 (2024) 9142\n[Tru2022] M.D. Truong\, A. Lagendijk & W.L. Vos\, Opt. Express 31\, 15058 (2023)\n[Upp2021] R. Uppu\, M. Adhikary\, C.A.M. Harteveld & W.L. Vos\, Phys. Rev. Lett. 126 (2021) 177402 \nAbout speaker\nWillem Vos obtained a Ph.D. in physics at the University of Amsterdam with highest honors (cum laude\, top 5%) for his thesis “Phase behavior of simple systems at high pressure”. He held a prestigious Fellowship from the Carnegie Institution for Science (USA) where he discovered a novel class of “van der Waals compounds” at very high pressures in the Geophysical Laboratory (Nature 1992).\nHe then became one of the first to study photonic crystals at optical frequencies\, niftily combining colloid physics and synchrotron X-ray methods. His team developed powerful “inverse opal” photonic crystals\, reported in an influential Science paper (~2400 Google citations). Since 2002 Vos is professor of Complex Photonic Systems (COPS) at the University of Twente. His team demonstrated the first ever control of spontaneous emission of light with photonic crystals (Nature 2004)\, and with a complete 3D photonic band gap (PRL 2011).\nHis COPS team pioneered optical wavefront shaping\, a revolution in optics to “unscatter” scattered light\, leading to novel applications in imaging\, microscopy\, and optical communication using opaque materials. Vos leads major multi-million-euro-consortia that closely collaborate with major high-tech industries and SMEs (with 30 BEUR annual turnover)\, to solve practical high-tech problems with advanced nanophotonics.\nVos was elected Fellow of the APS and of Optica (formerly: OSA)\, and awarded the Snellius medal and the Descartes-Huygens prize by the French Académie des Sciences. He has been guest professor at leading institutions (LPMMC\, CNRS\, Grenoble\, and Langevin Institute\, ESPCI\, PSL\, Paris). His papers are on average cited >40x. Willem Vos takes much pride in his students who have become faculty members at leading institutes\, or pursue careers in major industries as well as in non-profit organizations. \n  \n \n 
URL:https://unam.bilkent.edu.tr/en/event/engineering-light-to-hop-or-walk-through-photonic-nanostructures-fundamental-puzzles-to-sustainable-industrial-applications/
CATEGORIES:UNAM Seminars
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