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SUMMARY:IEM Distinguished Lecturers Seminar: Modulation and routing of non
 linear optical signals with metasurfaces above GHz rates
DTSTART:20250408T131500
DTEND:20250408T140000
DTSTAMP:20260524T182939Z
UID:4a3733c6974b9869c5d4d84286d6dd77ece1600e490c3aea9ecb529e
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Michele Celebrano\, Physics Department\, Politecnico di 
 Milano\, Italy\n***Coffee and Sweets will be served at 13:00 in the hall o
 f BM 5202***\n\nAbstract\nOptical metasurfaces are rapidly gaining tractio
 n as ultrathin multifunctional platforms for light management. Their capab
 ility to shape the wavefront of light makes them ideal for free-space opti
 cal analog computing. In this framework\, the fast reconfigurability of me
 tasurfaces constitutes an indisputable requirement to secure practical app
 lication. To date\, electro-optical and all-optical modulation represent t
 he foremost approaches for light manipulation through metasurfaces\, thank
 s to the compatibility with CMOS technology and the modulation rates above
  the GHz. Yet\, fast modulation often comes at the expense of optical sign
 als modulation depths (i.e. efficiency).\nThe last decades witnessed major
  efforts in the field of nanophotonics to attain efficient nonlinear optic
 al effects in nanoscale volumes. The main challenge in this scenario resid
 es in the perturbative character of the nonlinear interactions in nanoscal
 e systems. A key strategy to circumvent this limitation is to boost light
 –matter interaction by leveraging optical resonances in engineered nanoa
 ntennas and metasurfaces [1]. While conversion efficiencies at the nanosca
 le will unlikely reach those of bulk nonlinear crystals\, the nonlinear ch
 aracter of these signals grants higher sensitivity to environmental change
 s compared to linear signals. This enables strong signal modulation depths
  at the nanoscale [2]\, fueling the development of nonlinear metasurfaces 
 for electro- and all-optical light manipulation (e.g. modulation\, steerin
 g and amplification).\nIn this seminar\, I will show our latest approaches
  to light modulation and routing by means of optical metasurfaces based on
  highly nonlinear materials\, namely lithium niobate (LiNbO3) and aluminum
  gallium arsenide (AlxGa1-xAs). First\, I will present a LiNbO3 metasurfac
 e design\, empowered by quasi bound states in the continuum (q-BIC) resona
 nces\, that allows realizing electro-optic modulation of optical signals a
 t telecom wavelengths with efficiency exceeding 10% at rates above the GHz
  [3]. Noteworthy\, this platform also achieves a record modulation of the 
 second harmonic generated by a CW pump laser of more than one order of mag
 nitude. Finally\, by means of a periodic AlxGa1-xAs metasurfaces\, I will 
 demonstrate all-optical routing and polarization modulation of upconverted
  optical signals exploiting nonlinear interferometry [4\,5]. These experim
 ental realizations allow envisioning modulation rates approaching that of 
 the light optical cycle and can be employed for the realization of enhance
 d sensing platforms.\n\nReferences\n[1] L. Bonacina\, P.-F. Brevet\, M. Fi
 nazzi\, and M. Celebrano “Harmonic Generation at the Nanoscale” Journa
 l of Applied Physics 127\, 230901 (2020)\n[2] M. Celebrano et al. “Optic
 al tuning of dielectric nanoantennas for thermo-optically reconfigurable n
 onlinear metasurfaces” Opt. Lett. 46 2453-2456 (2021).\n[3] A. Di France
 scantonio et al. “Efficient GHz electro-optical modulation with a nonloc
 al lithium niobate metasurface in the linear and nonlinear regime” submi
 tted. https://arxiv.org/abs/2412.03422\n[4] A. Di Francescantonio et al. 
 “All-optical free-space routing of upconverted light by metasurfaces via
  nonlinear interferometry”\, Nat. Nanotechnology (2023). https://doi.org
 /10.1038/s41565-023-01549-2\n[5] Y. Luan\, et al. “All-optical polarizat
 ion control and routing by nonlinear interferometry at the nanoscale”\, 
 submitted. https://arxiv.org/abs/2412.07714\n\n\nShort Bio\nMichele Celebr
 ano (https://www.fisi.polimi.it/en/staff/michele.celebrano) is Associate P
 rofessor at the Department of Physics of Politecnico di Milano and PI at t
 he “supra Nano-Optics Milano” sNOm Lab (https://www.fisi.polimi.it/en/
 research-labs/snom)\, currently investigating the linear and nonlinear opt
 ical properties of nanoantennas and metasurfaces with the aim of exploitin
 g nonlinear upconversion processes for sensing\, optical logic operations 
 and THz generation.\nHe received his PhD in Physics in 2008 at Politecnico
  di Milano under the supervision of Prof. Giulio Cerullo and successively 
 worked as Post-Doc in the Nano-Optics Group led by Prof. Vahid Sandoghdar 
 at ETH Zurich (2008-11).\nHe currently Associate Editor at Optics Express 
 and chair of the ‘Plasmonics and Metamaterial’ Committee of the CLEO-E
 QEC Congress. He published more than 150 among scientific papers and confe
 rence proceedings with more than 4000 citations and received the Italian h
 abilitation to Full-Professor in 2020.\n 
LOCATION:BM 5202 https://plan.epfl.ch/?room==BM%205202 https://epfl.zoom.u
 s/j/63124898719
STATUS:CONFIRMED
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