Single-shot ultrafast laser fabrication of nanochannels with ∼60 nm feature size through polymeric film

Ultrafast laser fabrication of nanochannels in polymeric membranes could enable superior performance compared to conventional methods in terms of scalability, precision, and patterning controllability. However, achieving sub-100 nm features has been fundamentally limited by diffracting limits and thermal effects during laser-polymer interactions. Here, we demonstrate single-shot fabrication of bottleneck-shaped nanochannels through PET films using ultrafast Bessel beams, achieving 59 nm constrictions-a feature size well below the optical diffracting limit. This result is achieved through precise control of the thermal-affected zone and the interaction between the superficial and internal ablations. The technique additionally produces microchannels with morphological versatility. This work enables precise nanofabrication with applications in single-molecule sensing, oriented ion transport, and water treatment.