Broadband antireflection coatings for visible and infrared ranges

Antireflection coatings are among the most common and spread optical coatings that are used in every optical system in order to decrease losses and prevent shadow images. For space applications, they are critical elements which specifications will highly influence the overall optical systems performances. Despite the very wide range of developments that have been carried out over the past thirty years, the production of broadband antireflection coatings for visible and infrared ranges remains a challenge. In this paper, we will present some recent results based on thin film technology for the production of antireflection coatings dedicated to visible, near-IR and mid-IR spectral ranges. We will first present broadband antireflection coatings for [400-1100] nm spectral range We will present two type of coatings, one for normal and one for oblique incidence. Experimental demonstration by plasma assisted reactive magnetron sputtering using a Buhler HELIOS machine will be presented. We will then show antireflection coatings covering the [1.5-15] mu m range. Experimental demonstration and limitation will be presented.