Interferometric scattering for optical tomoslicing of transparent solids

While light scattering is widely utilized in optical metrology and measurement, it has long been regarded as detrimental in laser-material processing. Here, we report an interferometric scattering effect that overturns this conventional view by resolving the six-decade challenge of axial resolution in optical manufacturing. This breakthrough elevates the axial resolution from micrometers, e.g., ~2 µm in transparent solids slicing, to the sub-10 nm level. The underlying mechanism involves the controlled sequential generation of nano-scatterers through interference between the incident laser and deliberately seeded scattering centers. Based on this phenomenon, we developed an interferometric scattering-based optical tomoslicing technology (i-SOT), achieving kerf widths as narrow as 7 nm under an industrial standard efficiency of up to 400 mm²/s. This unprecedented axial resolution enables nearly lossless laser wafering from ingots-reducing mass loss from ~30% to below 1% - with transformative potential for manufacturing laser crystals, photovoltaics, and microelectronic chips.