Extended Data Fig. 3: Phonon spectra of YIG.
Complex dielectric function ε(ω) = ε1(ω) + iε2(ω) (black) and the imaginary part of the dielectric loss functions Im(−1/ε) (red) of YIG obtained by direct inversion of ellipsometric spectra. Vertical dashed lines indicate zero crossing of ε1(ω).
