Plasma-activated direct bonding of coated optical glasses

For the manufacturing of space-qualified spectrometric applications, the benefits of direct bonding are highly promising. While there are some recent spectrometric design concepts which rely on the usage of optical coatings, the direct bonding of optical glasses with added optical coatings is still challenging. This work presents investigations on plasma-activated direct bonding of optical glasses without and with added optical coatings. As a result, it is highly beneficial to add an additional SiO2 final layer onto the coating and to perform an additional chemical-mechanical polishing process prior to direct bonding in order to achieve high bonding strengths.