Figure 2:

Linear response of Na-based thin films. Dependence over the pump wavelength λ and incidence angle θ of the (a, c) absorbance A ^(TE,TM) and (b, d) reflectance R ^(TE,TM) (full curves) and transmittance T ^(TE,TM) (dahsed curves) for (a, b) TE and (c, d) TM excitation of a Na-based thin film with thickness d = 300 nm. The dashed white curves in (a, c) indicate the NZI dispersion curve θ _NZI(λ).