Low-Temperature Packaging Process of Quartz Optical Vacuum Cavities with Hydroxide-Catalysis Bonding

This paper presents a low-temperature process for fabricating compact optical quartz vacuum cavities based on hydroxide-catalysis bonding technology. This study conducted pre-experiments to investigate the effects of bonding solution, curing temperature, setting time on the bonding of quartz glass, and optimized a set of optimal bonding schemes for the current experimental conditions. The study showed that the bonding strength of Na₂SiO₃ solution at both concentrations was generally higher than that of NaOH; 1:6 Na₂SiO₃ solution bonding with accelerated curing at 80℃ was able to achieve a tensile strength of not less than 12 MPa and shortened the curing time to 1 day. The setting time of Na₂SiO₃ solution bonding is shorter than NaOH solution, probably only 30 s but sufficient for some applications. A quartz optical vacuum cavity was designed and successfully fabricated according to this scheme, showing that the overall leakage rate was better than 5.66×10⁻¹² Pa·m³·s⁻¹ and good thermal stability after thermal cycling tests. This study provides a feasible solution for the fabrication of a compact quartz glass optical vacuum cavity with low cost, simple process and excellent performance.