2024/11/12 by Nørgaard, Martin, Yezekyan, Torgom, Rolfs, Stefan +3
#FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Optics (physics.optics)
paper · doi:10.48550/arxiv.2411.07926
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 1570 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.