Near-field refractometry of van der Waals crystals.

ABSTRACT: 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.

SUBMITTER: Norgaard M 

PROVIDER: S-EPMC12273539 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature