Atmospheric pressure dielectric barrier discharge plasma-enhanced optical contact bonding of different types of optical glasses

Joining processes without using joining materials is the solution to meet the growing quality requirements in optical production. They are a superior alternative to classic fine cementing. To meet this demand, processes such as direct bonding have been successfully adopted by the wafer industry and optics manufacturing. To date, optical contact bonding with activated surfaces has only been tested successfully on pure glass surfaces or coated fused silica with coatings made of dielectric materials. Our previous work developed a process based on a dielectric barrier discharge plasma at atmospheric pressure, which successfully bonded fused silica optics with sensitive functional optical layers. This contribution introduces the further development of this approach for bonding different types of common optical multi-component glasses that differ from fused silica and each other decisive in terms of chemical composition, manufacturing qualities, and optical properties such as index of refraction and dispersion characteristics. All investigated glasses were successfully bonded by applying the developed process and in nearly all cases, mentionable high bond strengths were achieved. Hence, possible bonding mechanisms leading to the different bond strengths observed are discussed here.