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- 2019
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Tidskriftsartikel (refereegranskat)
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- Bakalis, Serafim, et al.
(författare)
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Perspectives from CO+RE : How COVID-19 changed our food systems and food security paradigms.
- 2020
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Ingår i: Current Research in Food Science. - : Elsevier BV. - 2665-9271. ; 3, s. 166-172
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Tidskriftsartikel (refereegranskat)abstract
- Within a few weeks the world has changed, at the time this text is written (May 2020) more than 3.5 million people have been confirmed cases of COVID-19 and estimations propose up to a hundred times the number of actually infected. A third of the global population is on lockdown and a large part of our global economic activity has stopped. Food and access to food has played a visual role in portraying the impact of the outbreak on our society, with images of empty supermarket shelves appearing in mainstream media. In some countries closed schools resulted in many children not having access to free meals and mobilised a number of charities. While parts of the world are now exiting lockdown and measures start relaxing the near future remains uncertain with more waves of the pandemic expected. Given that there is currently no evidence to show that transmission of COVID-19 could occur through food or food packaging there has been limited discussion on the issue, implications and potential future scenarios within the wider food science community.Within the food research community, up to the pandemic crisis the discourse has been dominated with design and manufacture of healthy and safe foods. The main issues are relevant to sustainability, circular economy, energy and water efficiency, climate friendly practices of products and processes. Efficiency has been the focus, but resilience has not been a significant issue so far. The term food system resilience has been defined by Tendalla (Tendalla et al., 2015) as ‘capacity over time of a food system and its units at multiple levels, to provide sufficient, appropriate and accessible food to all, in the face of various and even unforeseen disturbances’. We believe that in the future we will continue to see similar pressures in the food system, e.g., comparable pandemics, effects of climate change on food production, and that resilience will become of major importance.This commentary aims to present a reflection from the past, considering the present situation to provide thoughts on the actions needed to ensure resilient food systems.
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3. |
- Kilic, Ufuk, et al.
(författare)
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Broadband Enhanced Chirality with Tunable Response in Hybrid Plasmonic Helical Metamaterials
- 2021
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Ingår i: Advanced Functional Materials. - : WILEY-V C H VERLAG GMBH. - 1616-301X .- 1616-3028. ; 31:20
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Tidskriftsartikel (refereegranskat)abstract
- Designing broadband enhanced chirality is of strong interest to the emerging fields of chiral chemistry and sensing, or to control the spin orbital momentum of photons in recently introduced nanophotonic chiral quantum and classical optical applications. However, chiral light-matter interactions have an extremely weak nature, are difficult to control and enhance, and cannot be made tunable or broadband. In addition, planar ultrathin nanophotonic structures to achieve strong, broadband, and tunable chirality at the technologically important visible to ultraviolet spectrum still remain elusive. Here, these important problems are tackled by experimentally demonstrating and theoretically verifying spectrally tunable, extremely large, and broadband chiroptical response by nanohelical metamaterials. The reported new designs of all-dielectric and dielectric-metallic (hybrid) plasmonic metamaterials permit the largest and broadest ever measured chiral Kuhns dissymmetry factor achieved by a large-scale nanophotonic structure. In addition, the strong circular dichroism of the presented bottom-up fabricated optical metamaterials can be tuned by varying their dimensions and proportions between their dielectric and plasmonic helical subsections. The currently demonstrated ultrathin optical metamaterials are expected to provide a substantial boost to the developing field of chiroptics leading to significantly enhanced and broadband chiral light-matter interactions at the nanoscale.
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4. |
- Kilic, Ufuk, et al.
(författare)
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Controlling the broadband enhanced light chirality with L-shaped dielectric metamaterials
- 2024
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Ingår i: Nature Communications. - 2041-1723. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- The inherently weak chiroptical responses of natural materials limit their usage for controlling and enhancing chiral light-matter interactions. Recently, several nanostructures with subwavelength scale dimensions were demonstrated, mainly due to the advent of nanofabrication technologies, as a potential alternative to efficiently enhance chirality. However, the intrinsic lossy nature of metals and the inherent narrowband response of dielectric planar thin films or metasurface structures pose severe limitations toward the practical realization of broadband and tailorable chiral systems. Here, we tackle these problems by designing all-dielectric silicon-based L-shaped optical metamaterials based on tilted nanopillars that exhibit broadband and enhanced chiroptical response in transmission operation. We use an emerging bottom-up fabrication approach, named glancing angle deposition, to assemble these dielectric metamaterials on a wafer scale. The reported strong chirality and optical anisotropic properties are controllable in terms of both amplitude and operating frequency by simply varying the shape and dimensions of the nanopillars. The presented nanostructures can be used in a plethora of emerging nanophotonic applications, such as chiral sensors, polarization filters, and spin-locked nanowaveguides.
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5. |
- Kilic, Ufuk, et al.
(författare)
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Tunable plasmonic resonances in Si-Au slanted columnar heterostructure thin films
- 2019
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- We report on fabrication of spatially-coherent columnar plasmonic nanostructure superlattice-type thin films with high porosity and strong optical anisotropy using glancing angle deposition. Subsequent and repeated depositions of silicon and gold lead to nanometer-dimension subcolumns with controlled lengths. We perform generalized spectroscopic ellipsometry measurements and finite element method computations to elucidate the strongly anisotropic optical properties of the highly-porous Si-Au slanted columnar heterostructures. The occurrence of a strongly localized plasmonic mode with displacement pattern reminiscent of a dark quadrupole mode is observed in the vicinity of the gold subcolumns. We demonstrate tuning of this quadrupole-like mode frequency within the near-infrared spectral range by varying the geometry of Si-Au slanted columnar heterostructures. In addition, coupled-plasmon-like and inter-band transition-like modes occur in the visible and ultra-violet spectral regions, respectively. We elucidate an example for the potential use of Si-Au slanted columnar heterostructures as a highly porous plasmonic sensor with optical read out sensitivity to few parts-per-million solvent levels in water.
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