Laser-induced damage in gradual index layers and Rugate filters

Abstract

The development of advanced and reliable techniques for the production of optical coating systems with a continuous variation of the refractive index opens the way towards a new generation of optical components in laser technology and modern optics. The present paper is dedicated to an Ion Beam Sputtering (IBS) concept for the production of coatings with gradual index layers and Rugate filters. On the basis of a spectrophotometric online-control system, Rugate filter coatings were produced with high precision and reliability. In addition to the optical performance, especially the laser damage properties of the coating systems were investigated with respect to defined mixtures of two coating materials and the influence of gradual index layer designs. A dramatic increase of the laser induced damage threshold was observed for the produced Rugate coatings. The experimental results are discussed considering the special properties of gradual coating systems.