I ran a simulation using the Transfer Matrix Method to plot the R,T and A curves for a SiC->SiO2 interface. There's a region of incident energies where the |r|^2 I get is higher than 1 and the transmittance is lower than zero. I wonder what the reason for that could be and I'd appreciate if someone has an idea:
I even tried calculating by hand and got the same result. The parameters I used for the calculation:
Energy of incident ray = 0.0973eV (p polarization, 30 degrees incident angle).
Relative permittivity of SiC at this energy = 85.474 + j*15.1456 .
Relative permittivity of SiO2 at this energy = 0.58 + j*1.0627 .
Wave number at the direction of propagation (SiC) = (3.9633 + j*0.3484)*10^6 [1/m] .
Wave number at the direction of propagation (SiO2) = (0.147 - j*2.253)*10^6 [1/m] .
I used the following equations (taken from an article by Tianrong Zhan from 2013):
From the transfer matrix the reflectance is achieved by: $r=\frac{M_{21}}{M_{11}} \rightarrow R = |r|^2$
