Modification of polysilsesquioxane curing for use in anti-reflective coatings

In this work we showcase the formulation of an anti-reflective (AR), UV/ozone-curable polysilsesquioxane or glass resin (GR) system with a high laser damage threshold suitable for Third-Harmonic Generator (THG) optics. Potassium Dideuterium Phosphate (DKDP) single crystals are used for these non-linear optics at the National Ignition Facility (NIF). However, DKDP is thermally sensitive making it crucial to avoid elevated thermal conditions, therefore UV/ozone-curing glass resins are the optimal choice. The commercial GR, utilized in this study was specifically engineered to undergo complete curing during UV processing, while also offering the flexibility of a low thermal cure at temperatures below 100 °C. UV/ozone exposure resulted in a significant loss of methyl silane peaks and a thermally cured network formed a total reduction of R-OH & Si-OH peaks. Laser damage testing confirmed equivalent damage-resistance for each network based on their curing condition. The newly formulated GR is a highly shelf-stable solution that allows peak optical performance on large-high-power laser systems where unique optics and operating conditions exist.