Composition of the thin membrane and how the light from the laser interacts in its interior. The membrane consists of three films: (a) an aluminum coating of width h₁, (b)  a CVD-diamond substrate of width h₂, and (c)  an aluminum or gold coating, of width h₃. Left: the shape of the clamped-edge membrane, h_m(r), is only depending on r, and in the classical adaptive optics implementations, the gravity vector is vertical. Right: a linearly polarized plane wave (E_in, H_in) is normally incident on the surface of a medium of complex dielectric constant ϵ₁. E_1t, E_1r are the electric fields inside the first reflective medium for, the transmitted and reflected waves respectively. For a good reflection of light with aluminum or gold, the thickness of the coating must be greater than 50 nm and the two electric fields inside with medium will be strongly attenuated. In this case, E_2t, E_2r,E_t inside and outside the CVD-diamond will be equal to zero. is the free-space impedance and the H-field amplitude will be always depending on the relative permittivity ϵ of the medium.