Near-field refractometry of van der Waals crystals

Common techniques for measuring refractive indices, such as ellipsometry and goniometry, are ineffective for van der Waals crystal flakes because of their high anisotropy and small, micron-scale, lateral size. To address this, we employ near-field optical microscopy to analyze the guided optical mod...

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Main Authors: Nørgaard Martin, Yezekyan Torgom, Rolfs Stefan, Frydendahl Christian, Mortensen N. Asger, Zenin Vladimir A.
Format: Article
Language:English
Published: De Gruyter 2025-05-01
Series:Nanophotonics
Subjects:
Online Access:https://doi.org/10.1515/nanoph-2025-0117
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author Nørgaard Martin
Yezekyan Torgom
Rolfs Stefan
Frydendahl Christian
Mortensen N. Asger
Zenin Vladimir A.
author_facet Nørgaard Martin
Yezekyan Torgom
Rolfs Stefan
Frydendahl Christian
Mortensen N. Asger
Zenin Vladimir A.
author_sort Nørgaard Martin
collection DOAJ
description Common techniques for measuring refractive indices, such as ellipsometry and goniometry, are ineffective for van der Waals crystal flakes because of their high anisotropy and small, micron-scale, lateral size. To address this, we employ near-field optical microscopy to analyze the guided optical modes within these crystals. By probing these modes in MoS2 flakes with subwavelength spatial resolution at a wavelength of 1,570 nm, we determine both the in-plane and out-of-plane permittivity components of MoS2 as 16.11 and 6.25, respectively, with a relative uncertainty below 1 %, while overcoming the limitations of traditional methods.
format Article
id doaj-art-68a72ec341ff4994abcd83422161cdbe
institution Kabale University
issn 2192-8614
language English
publishDate 2025-05-01
publisher De Gruyter
record_format Article
series Nanophotonics
spelling doaj-art-68a72ec341ff4994abcd83422161cdbe2025-08-20T03:28:19ZengDe GruyterNanophotonics2192-86142025-05-0114142473248310.1515/nanoph-2025-0117Near-field refractometry of van der Waals crystalsNørgaard Martin0Yezekyan Torgom1Rolfs Stefan2Frydendahl Christian3Mortensen N. Asger4Zenin Vladimir A.5POLIMA – Center for Polariton-driven Light– Matter Interactions, 594932University of Southern Denmark, Campusvej 55, DK-5230, Odense M, DenmarkPOLIMA – Center for Polariton-driven Light– Matter Interactions, 594932University of Southern Denmark, Campusvej 55, DK-5230, Odense M, DenmarkCenter for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, DenmarkCenter for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, DenmarkPOLIMA – Center for Polariton-driven Light– Matter Interactions, 594932University of Southern Denmark, Campusvej 55, DK-5230, Odense M, DenmarkCenter for Nano Optics, University of Southern Denmark, Campusvej 55, DK-5230, Odense M, DenmarkCommon techniques for measuring refractive indices, such as ellipsometry and goniometry, are ineffective for van der Waals crystal flakes because of their high anisotropy and small, micron-scale, lateral size. To address this, we employ near-field optical microscopy to analyze the guided optical modes within these crystals. By probing these modes in MoS2 flakes with subwavelength spatial resolution at a wavelength of 1,570 nm, we determine both the in-plane and out-of-plane permittivity components of MoS2 as 16.11 and 6.25, respectively, with a relative uncertainty below 1 %, while overcoming the limitations of traditional methods.https://doi.org/10.1515/nanoph-2025-0117snomvdw crystalsrefractive index
spellingShingle Nørgaard Martin
Yezekyan Torgom
Rolfs Stefan
Frydendahl Christian
Mortensen N. Asger
Zenin Vladimir A.
Near-field refractometry of van der Waals crystals
Nanophotonics
snom
vdw crystals
refractive index
title Near-field refractometry of van der Waals crystals
title_full Near-field refractometry of van der Waals crystals
title_fullStr Near-field refractometry of van der Waals crystals
title_full_unstemmed Near-field refractometry of van der Waals crystals
title_short Near-field refractometry of van der Waals crystals
title_sort near field refractometry of van der waals crystals
topic snom
vdw crystals
refractive index
url https://doi.org/10.1515/nanoph-2025-0117
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AT yezekyantorgom nearfieldrefractometryofvanderwaalscrystals
AT rolfsstefan nearfieldrefractometryofvanderwaalscrystals
AT frydendahlchristian nearfieldrefractometryofvanderwaalscrystals
AT mortensennasger nearfieldrefractometryofvanderwaalscrystals
AT zeninvladimira nearfieldrefractometryofvanderwaalscrystals