Modelling and nanofabrication of chiral dielectric metasurfaces
Polarization control through all-dielectric metasurfaces holds great potential in different fields, such as telecommunications, biochemistry and holography. Asymmetric chiral metasurfaces supporting quasi-bound states in the continuum may prove very useful for controlling and manipulating the polari...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-06-01
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| Series: | Micro and Nano Engineering |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2590007223000175 |
| _version_ | 1797798646946725888 |
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| author | Luca Fagiani Marco Gandolfi Luca Carletti Costantino de Angelis Johann Osmond Monica Bollani |
| author_facet | Luca Fagiani Marco Gandolfi Luca Carletti Costantino de Angelis Johann Osmond Monica Bollani |
| author_sort | Luca Fagiani |
| collection | DOAJ |
| description | Polarization control through all-dielectric metasurfaces holds great potential in different fields, such as telecommunications, biochemistry and holography. Asymmetric chiral metasurfaces supporting quasi-bound states in the continuum may prove very useful for controlling and manipulating the polarization state of light. A crucial quantity for characterizing the optical chirality is the circular dichroism (CD). In this work we analyse how the CD and quality factor of the optical mode can be strongly influenced by a nanofabrication error. Modelling the nanofabrication uncertainties on the gaps of the chiral metasurface, the imperfections of the etchings process or the modification of the asymmetry factor, we found that the proper engineering of the gap between the nanostructures of the unit cell is the most important parameter to achieve a high-quality factor and enhanced optical dichroism. An optimization of the nanofabrication processes, such as dose factor, dwell time and plasma etching demonstrates that, for a writing field of 100 μm2, it is possible to obtain morphologically precise chiral metasurfaces, with fabrication uncertainties lower than those that would limit Q factor and chirality property. |
| first_indexed | 2024-03-13T04:08:00Z |
| format | Article |
| id | doaj.art-0f1100afe6ff466183f5d3eb09ac1503 |
| institution | Directory Open Access Journal |
| issn | 2590-0072 |
| language | English |
| last_indexed | 2024-03-13T04:08:00Z |
| publishDate | 2023-06-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Micro and Nano Engineering |
| spelling | doaj.art-0f1100afe6ff466183f5d3eb09ac15032023-06-21T06:58:54ZengElsevierMicro and Nano Engineering2590-00722023-06-0119100187Modelling and nanofabrication of chiral dielectric metasurfacesLuca Fagiani0Marco Gandolfi1Luca Carletti2Costantino de Angelis3Johann Osmond4Monica Bollani5Department of Physics, Politecnico di Milano, Piazza Leonardo Da Vinci 32, 20133 Milano, ItalyDepartment of Information Engineering, University of Brescia, Via Branze 38, 25123 Brescia, Italy; INO-CNR, Via Branze 45, Brescia, 25123, Italy; CNIT, Viale G.P. Uberi 181/A, 43124 Parma, ItalyDepartment of Information Engineering, University of Brescia, Via Branze 38, 25123 Brescia, Italy; INO-CNR, Via Branze 45, Brescia, 25123, Italy; CNIT, Viale G.P. Uberi 181/A, 43124 Parma, ItalyDepartment of Information Engineering, University of Brescia, Via Branze 38, 25123 Brescia, Italy; INO-CNR, Via Branze 45, Brescia, 25123, Italy; CNIT, Viale G.P. Uberi 181/A, 43124 Parma, ItalyICFO (Institut de Ciencies Fotoniques), The Barcelona Institute of Science and Technology, 08860 Castelldefels, (Barcelona), SpainCNR - IFN, LNESS Laboratory, Via Anzani 42, 22100 Como, Italy; Corresponding author.Polarization control through all-dielectric metasurfaces holds great potential in different fields, such as telecommunications, biochemistry and holography. Asymmetric chiral metasurfaces supporting quasi-bound states in the continuum may prove very useful for controlling and manipulating the polarization state of light. A crucial quantity for characterizing the optical chirality is the circular dichroism (CD). In this work we analyse how the CD and quality factor of the optical mode can be strongly influenced by a nanofabrication error. Modelling the nanofabrication uncertainties on the gaps of the chiral metasurface, the imperfections of the etchings process or the modification of the asymmetry factor, we found that the proper engineering of the gap between the nanostructures of the unit cell is the most important parameter to achieve a high-quality factor and enhanced optical dichroism. An optimization of the nanofabrication processes, such as dose factor, dwell time and plasma etching demonstrates that, for a writing field of 100 μm2, it is possible to obtain morphologically precise chiral metasurfaces, with fabrication uncertainties lower than those that would limit Q factor and chirality property.http://www.sciencedirect.com/science/article/pii/S2590007223000175Chiral metasurfaceCircular dichroismDielectric metasurfaceQuality factorEBLThird-harmonic generation |
| spellingShingle | Luca Fagiani Marco Gandolfi Luca Carletti Costantino de Angelis Johann Osmond Monica Bollani Modelling and nanofabrication of chiral dielectric metasurfaces Micro and Nano Engineering Chiral metasurface Circular dichroism Dielectric metasurface Quality factor EBL Third-harmonic generation |
| title | Modelling and nanofabrication of chiral dielectric metasurfaces |
| title_full | Modelling and nanofabrication of chiral dielectric metasurfaces |
| title_fullStr | Modelling and nanofabrication of chiral dielectric metasurfaces |
| title_full_unstemmed | Modelling and nanofabrication of chiral dielectric metasurfaces |
| title_short | Modelling and nanofabrication of chiral dielectric metasurfaces |
| title_sort | modelling and nanofabrication of chiral dielectric metasurfaces |
| topic | Chiral metasurface Circular dichroism Dielectric metasurface Quality factor EBL Third-harmonic generation |
| url | http://www.sciencedirect.com/science/article/pii/S2590007223000175 |
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