Optical coating design with reduced electric field intensity

A method is outlined for improving the laser-damage resistance of multilayer optical coatings by suppressing the peak value of the electric-field intensity within the critical layer of the coating. Designs are described for reflectors in which the electric-field intensity in high-refractive-index films is lower than in conventional designs. Equations and tables are provided for designing such reflectors with two or more altered layers. It is noted that modified designs with reduced electric-field intensity in one layer inevitably have increased field intensity in an adjacent layer, so that the limit of the proposed method will be determined by the laser-damage threshold within the stronger of the two materials.