Ultrafast laser bonding of glasses and crystals to metals for epoxy-free optical instruments

摘要

The use of epoxies in space-based instruments is often unavoidable in situations where the bonding of dissimilar materials such as glass and metal is required. While there are epoxies that exhibit low total mass loss (TML) and collected volatile condensable materials (CVCM) in vacuum, in some applications they can still be a source of problematic contamination. Epoxies can also be incompatible with exposure to chemical environments some space instrumentation may be exposed to. In high power laser instruments such as LIDAR systems where optical components must be securely bonded to metal mounts, the impact of epoxy outgassing can be especially acute. Even with very low outgassing levels, the intense laser can break down the outgassed material and preferentially deposit it on optics that handle high optical power. This laser induced contamination in turn leads to laser induced damage, leading to degradation of optical components and reducing the reliability and operational lifetime of laser instruments [1-6]. Alternative bonding methods that avoid introducing additional contaminants could greatly improve reliability and operational lifetime of space instruments.