Fig. 3: Experimental results for monolayer MoS₂ immersed in polydimethylsiloxane.

Black dots: experimental data, colored dots: extracted optical constants, lines: theoretical fits for the four models considered in this paper. a, b Ellipsometric parameters Ψ_i and Δ_i. Neither the iso_slab model nor the curr_0 model fits the data, using as optical constants those extracted from the Ψ_s and Δ_s. c, d Optical constants determined with slab and the curr model. They predict similar χ_∥ and σ_∥, but negative and positive χ_⊥ respectively, and σ_⊥ compatible with 0 Ω⁻¹. The error bars reported are the standard deviation of these values (see Table 1). e Reflectivities for s and p polarized light. Experimental data show a pseudo Brewster angle for R_ip. The iso_slab model fails to predict its position by almost 7°. The curr_0 model does not predict it at all. All models fit R_is reasonably well (for clarity we show only the curr model and the slab model).