A device for altering an intensity distribution of a laser radiation field contains two substrates with differing refractive indices and with two opposed, mutually corresponding optical functional boundary surfaces, which are at least partly curved. The laser radiation field for altering can pass serially through the optical functional boundary surfaces, whereby a difference in the refractive indices of the first and second substrate is less than 0.1 and the cavity, between the first optical functional boundary surface and the second optical functional boundary surface is embodied such that the laser radiation, on propagation from the first substrate into the second substrate, is essentially subjected to one refraction on the basis of the difference in the refractive indices of the first and second substrate.