Schematic representation of the interaction between an oblique incoming wave and a CHB, depending on the angle of the incident wave, θ_I. Five different scenarios are possible (assuming that the incoming wave is an enhancement): (a) no transmission in the x-direction and the reflection is a depletion, (b) no transmission and the reflection is an enhancement, (c) transmission in the x-direction and the reflection is an enhancement, (d) perfect transmission, also meaning that there is no reflection at all, (e) transmission in the x-direction and the reflection is a depletion.