Fig. 4: In-plane anisotropic dispersion of the waveguide modes at MIR band.
From: Visible to mid-infrared giant in-plane optical anisotropy in ternary van der Waals crystals
Experimental dispersion data (points) and theoretical dispersion relations of TM and TE polarized waveguide modes along (a, b) c-axis and (c, d) a-axis, respectively. The Ta2NiS5 sample is on CaF2 substrate and the thickness is 1785 nm. Im(r) represents the imaginary part of the Fresnel reflectivity coefficients. The error bars were determined from the half of the full-width at half-maximum (FWHM) of the peak in the Fourier transform (FT) analysis69. Polar plot of wavevector q along different in-plane crystallographic directions of the TM and TE modes under excitation wavelengths of (e, f) 4.545 μm and (g, h) 6.849 μm. The error bars were determined from the half of the FWHM of the peak in the FT analysis69.
