Flavia Timpu


Last Name

Timpu

First Name

Flavia

ORCID

0000-0002-0951-4070

Organisational unit

03892 - Home, Jonathan / Home, Jonathan

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2017 - 2019192020 - 202222
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Publications1 - 10 of 41
  • Electro-Optic Lithium Niobate Metasurfaces in the Visible
    Item type: Other Conference Item
    Vogler-Neuling, Viola V.; Weigand, Helena; Reig Escalé, Marc; et al. (2021)
  • Imprinted Barium Titanate Metalenses with broadband Focus
    Item type: Other Conference Item
    Weigand, Helena; Vogler-Neuling, Viola Valentina; Pitz, Oliver; et al. (2022)
    OSA Technical Digest ~ Conference on Lasers and Electro-Optics
    We present a metalens from barium titanate, a widely transparent and optically nonlinear material. We demonstrate broadband visible to near-infrared focusing using a simple soft nano-imprint fabrication to reach aspect-ratios of up to 8.
  • Top-down Fabrication Of Barium Titanate Metasurfaces With Transmission Filtering In The Visible
    Item type: Conference Paper
    Timpu, Flavia; Reig Escalé, Marc; Merkt, A.; et al. (2018)
    Proceedings of the 12th International Congress on Artificial Materials for Novel Wave phenomena
  • Metal-Dielectric Nanodimers with Hybridized Resonances Probed by Second-Harmonic Polarization
    Item type: Conference Paper
    Renaut, Claude; Lang, Lukas; Frizyuk, Kristina; et al. (2019)
    OSA Technical Digest ~ Conference on Lasers and Electro-Optics
  • Broadband Mie driven random quasi-phase-matching
    Item type: Journal Article
    Savo, Romolo; Morandi, Andrea; Müller, Jolanda S.; et al. (2020)
    Nature Photonics
    High-quality crystals without inversion symmetry are the conventional platform to achieve optical frequency conversion via three-wave mixing. In bulk crystals, efficient wave mixing relies on phase-matching configurations, while at the micro- and nanoscale it requires resonant mechanisms that enhance the nonlinear light-matter interaction. These strategies commonly result in wavelength-specific performances and narrowband applications. Disordered photonic materials, made up of a random assembly of optical nonlinear crystals, enable a broadband tunability in the random quasi-phase-matching regime and do not require high-quality materials. Here, we combine resonances and disorder by implementing random quasi-phase-matching in Mie resonant spheres of a few micrometres realized by the bottom-up assembly of barium titanate nanocrystals. The measured second-harmonic generation reveals a combination of broadband and resonant wave mixing, in which Mie resonances drive and enhance the second-harmonic generation, while the disorder keeps the phase-matching conditions relaxed. Our nanocrystal assemblies provide new opportunities for tailored phase matching at the microscale, beyond the coherence length of the bulk crystal. They can be adapted to achieve frequency conversion from the near-ultraviolet to the infrared ranges, are low cost and can cover large surface areas. Enhanced second-harmonic generation is achieved through random quasi-phase-matching in three-dimensional Mie resonant disordered microspheres realized by the bottom-up assembly of barium titanate nanocrystals.
  • Random quasi-phase-matching in bottom-up assemblies of nanoparticles into disordered microspheres
    Item type: Other Conference Item
    Savo, Romolo; Morandi, Andrea; Kaufmann, Fabian; et al. (2019)
    NANOP 2019. Functional Nanophotonics. Nanophotonics and Micro/Nano Optics International Conference / Sept 4-6, 2019, Munich. Book of Abstracts
  • Metasurfaces Of Barium Titanate As Filters In The Visible Range
    Item type: Conference Poster
    Timpu, Flavia; Reig Escalé, Marc; Merkt, A.; et al. (2018)
  • Electro-Optic Modulation of Transmission in a Lithium Niobate Metasurface
    Item type: Other Conference Item
    Weigand, Helena; Vogler-Neuling, Viola; Reig Escalé, Marc; et al. (2021)
    2021 MRS Fall Meeting & Exhibit: Abstract Book
  • Barium Titanate Nanostructures and Thin Films for Photonics
    Item type: Review Article
    Karvounis, Artemios; Timpu, Flavia; Vogler-Neuling, Viola V.; et al. (2020)
    Advanced Optical Materials
    Barium titanate (BaTiO3) is a synthetic crystal used in electromechanical transducers and multilayer ceramic capacitors. Since it is not available in nature, a variety of growth methods has been employed to produce in large scale, with high quality and low‐cost. BaTiO3, as a metal oxide meets practical requirements such as physical hardness, stability and tunable optoelectronic properties. The plethora of characteristics renders it functional in diverse fields of applications from energy harvesting to biophotonics. Related to optical properties, it is a dielectric material from the near ultraviolet to the near‐infrared part of the spectrum with low optical losses and relatively high refractive index. The strong second‐order nonlinear response has resulted in several breakthroughs in bioimaging, while its intrinsic electrooptic response is among the highest within the existing materials. The properties of the BaTiO3 may also be modified by doping or hybridization with other materials. This review presents the basic optoelectronic properties of BaTiO3, reports on the recent advances in BaTiO3 nanostructures and thin films related to photonic applications, and oversees photonic technologies that may benefit from this material platform in the near future.
  • Electro-optic tuning of nanostructured metasurfaces from lithium niobate
    Item type: Conference Poster
    Weigand, Helena; Timpu, Flavia; Kaufmann, Fabian; et al. (2020)
Publications1 - 10 of 41