Calculation of enhanced scattering peaks in disordered thin slabs with internal reflections

By performing first-principles calculations, we study theoretically the angular distributions of the intensities of the scattered waves which are reflected from and transmitted through disordered thin slabs with internal reflections in the case when L < l and λ < l, where L is the thickness of the slab, l is the mean free path, and λ is the wavelength inside the slab. We find that the enhanced scattering peak on the transmission side has almost the same structure as the coherent backscattering (CBS) peak on the reflection side when the phase factor Φ ≡ kL[√(m ²-sin² θ_i)/m] < 1, where k=2π/λ, m is the relative refractive index of the slab, and θ_i is the incident angle. When Φ > 1, the enhanced scattering peak on the transmission side shows an oscillatory behavior. The amplitudes of the oscillations increase with m and θ_i. It is also found that the widths of the enhanced scattering peaks increase with L. This is opposite to the well-known trend in thick slabs, where the width of the CBS peak decreases with L. When L > λ, we find satellite peaks, which are much weaker in intensity than the main enhanced scattering peaks.