A NEW METHOD FOR ELECTRIC FIELD OPTIMIZATION IN&

Spatial distribution of electric field amplitude has an essential role in laser-induced damage multi-layer coating. A new method introduced in this paper to reduce the electric field intensity effectively within the high index layers in multi-layer reflectors that are irradiated by high power lasers. The design is based on specific non-quarter wave pairs, assuming the number of layers is held constant. Using a combination of periodic and non-periodic pairs of a non-quarter wave stack with an appropriate thickness for a specific angle of incidence, minimum electric field can be obtained within the high index layers for the S or P polarization. Different results can be obtained if the non-periodic pairs are placed adjacent to the substrate, or to the ambient. We have shown that by the former design, a lower electric field can be achieved within the layers and the mirror can be optimized. The optimization was carried out for oblique incidence and the effect of angle of incidence was examined for both S and P polarizations.