A method for reducing the optical loss of the multilayer coating below a predetermined value in a zone by producing coating on a displaceable substrate in a vacuum chamber with the aid of a residual gas using a sputtering device. Reactive depositing a coating on the substrate by adding a reactive component with a predetermined stoichiometric deficit in a zone of the sputtering device. Displacing the substrate with the deposited coating into the vicinity of a plasma source, which is located in the vacuum chamber at a predetermined distance from the sputtering device. The plasma action of the plasma source modifying the structure and/or stoichiometry of the coating, preferably by adding a predetermined quantity of the reactive component to reduce the optical loss of the coating.