Research led by QUEST researcher Simon Horsley has been published in this month's issue of Nature Photonics (available online since June 22). In the letter, "Spatial Kramers–Kronig relations and the reflection of waves", a method is desacribed for producing media that do not reflect waves incident on the boundary. The method depends on varyng the permittivity of the medium spatially, such that its real and imaginary parts satisfy the Kramers-Kronig relationship in space. The letter features on the cover of the journal, which also uses an image from it.
Test of reflection for all angles of incidence by simulating a line source (pointing out of the screen) placed within the inhomogeneous permittivity profile satisfying the Kramers-Kronig relations: absolute electric field for a line source to the (i) left and (ii) right of a medium suppressing reflections when incident from the left; (iii) real and (iv) imaginary parts of the electric field for a line source on the left of the slab.