Polymer processing

Polymer conducts heat poorly, so a longer pulse melts, warps or chars the edge. Femtosecond pulses remove material before the heat spreads, which keeps cut edges clean: in polyimide the heat-affected zone measures 12.7 µm at 515 nm, and a 10 mm disc is cut from film in 400 ms.

Photopolymerization builds structures instead of removing material. Femtosecond pulses focused inside a liquid resin trigger two-photon absorption, which solidifies only the focal volume, so the focus can be scanned in three dimensions to write almost any geometry. The result is micrometer-scale parts for tissue engineering, optics, electronics and microfluidics.