A mirror having a mirror substrate (12, 32, 52), a reflection layer stack (21, 41, 61) reflecting electromagnetic radiation having an operating wavelength that is incident on the optical effective surface (11, 31, 51), and at least one piezoelectric layer (16, 36, 56), arranged between the substrate and the reflection layer stack and to which an electric field producing a locally variable deformation is applied. A first electrode arrangement (20, 40, 60) situated on the side of the piezoelectric layer faces the reflection layer stack, and a second electrode arrangement (14, 34, 54) is situated on the side of the piezoelectric layer facing the mirror substrate. Optionally, a bracing layer (98) is provided, which limits sinking of the piezoelectric layer (96) into the mirror substrate (92) when an electric field is applied, in comparison with an analogous construction lacking the bracing layer, thereby increasing the piezoelectric layer's effective deflection.