Figure 1

(a) Schematic illustration of geometry for vdW thin films (i.e. \(\alpha\)-\(\hbox {MoO}_3\) or \(\alpha\)-\(\hbox {V}_2\) \(\hbox {O}_5\)) on silicon substrate based polarizer and polarization rotator. (b, c) show real part of dielectric permittivities of \(\alpha\)-\(\hbox {MoO}_3\) and \(\alpha\)-\(\hbox {V}_2\) \(\hbox {O}_5\), respectively, along x, y and z crystallographic direction which reveal the natural biaxial hyperbolicity of \(\alpha\)-\(\hbox {MoO}_{{3}}\) and of \(\alpha\)-\(\hbox {V}_2\) \(\hbox {O}_5\) vdW crystals. Spectral region colored in green, red and blue represents Reststrahlen Bands (RBs) 1, 2 and 3 respectively. (Insets show isofrequency surfaces³⁷ in the respective RB spectral regions.) (d, e) represent the optical response of 100 nm thin film of \(\alpha\)-\(\hbox {MoO}_{{3}}\) for \(x-\) and y-polarized light respectively. (f, g) represent the optical responses of 100 nm thin film of \(\alpha\)-\(\hbox {V}_2\) \(\hbox {O}_5\) for x- and y-polarized light respectively. Scatter plots and line plots in (d–g) represent optical responses obtained from numerical simulations and TMM respectively. A, R and T in (d–g) correspond to absorbance, reflectance and transmittance respectively.