Frequency response mechanism of surface smoothing and material removal on fused silica

To meet the stringent requirements for sub-nanometer surface roughness and full-spectrum spatial frequency error control in high-precision optical systems, this study systematically investigates the effects of varying Cerium oxide (CeO₂) abrasive particle sizes and pitch pad hardness on the surface quality of fused silica glass during computer-controlled optical surfacing (CCOS). This study integrates experimental characterization with mathematical modeling to analyze the mechanisms by which abrasive particle size and polishing tool hardness influence material removal rates, contact pressure distribution, and surface roughness. The results indicate that smaller CeO₂ particles effectively reduce high-spatial frequency roughness, making them suitable for precise micro-surface finishing, while larger particles exhibit higher material removal efficiency, making them more suitable for macro-surface machining. Hard pitch pads induce greater indentation depth and concentrated pressure, significantly improving mid-spatial frequency surface errors, while softer pitch pads are more suitable for overall surface smoothing. Experimental findings further validate the feasibility and effectiveness of the proposed optimization strategies in achieving ultra-precision processing at picometer scales across the full spectrum of frequency bands. This study provides a theoretical basis and practical guidance for selecting process parameters in the manufacturing of high-precision optical components.