Periodic nanoscale structures on polyimide surfaces generated by temporally tailored femtosecond laser pulses.

A strong influence of different pulse durations and double pulse delay times on the formation of periodic surface structures on polyimide were observed employing ultrashort laser pulses tailored on a sub-picosecond and picosecond time scale. Multi-photon, defect-related excitation mechanisms and thermal expansion of the polymer lattice correlated to a loss of long range order and polarisation memory were considered.