Manufacture of ultra-smooth surface with low damage by elastic emission machining

Extreme application scenarios require atomic-level surface smoothness without subsurface damage, particularly for hard and brittle materials prone to cracks and residual stress during mechanical processing. Elastic emission machining (EEM), a non-destructive atomic-level material removal method, has gained significant attention. However, its ultra-smooth surface generation mechanism remains underexplored. This study comprehensively compares the surface morphology, subsurface damage, and material properties before and after EEM polishing from a multi perspective. EEM preferentially removes protruding defects, whereas pit-type subsurface defects with residual compressive stress require a greater material removal depth. Micron scratch experiments reveal the mechanisms of EEM in smoothing and flattening defects, demonstrating its effectiveness in eliminating micron-scale scratches and enabling the conformal polishing of submillimetre microstructure. EEM achieves ultra-smooth surfaces with roughness below 0.1 nm root mean square on fused quartz, monocrystalline silicon, and ULE. The surface and internal lattice integrity of monocrystalline silicon confirm the non-destructive polishing capability of EEM. Power spectral density calculation indicate that EEM can eliminate spatial wavelength errors in the micron to the nanometre scale. This study validates the potential of EEM in high-performance optical component manufacturing and provides valuable references for achieving non-destructive atomic-level processing.