Figure 4From: Study of the omnidirectional photonic bandgap for dielectric mirrors based on porous silicon: effect of optical and physical thicknessContour plot of the reflectivity spectra as a function of the angle and wavelength. (a, d) Sinusoidal, (b, e) Gaussian, and (c, f) Bragg refractive index profiles. The color scale indicates the reflectivity percentage from 0% (blue) to 100% (red).Back to article page