Visible-laser ablation on a nanometer scale using urethane-urea copolymers

We report visible-laser ablation of a urethane-urea copolymer containing an azo dye. The ablated depth on the copolymer film was proportional to incid ent laser energy. The linearity of a depth/energy conversion on a nanometer scale was, ensured at very low beam energy (similar to 2 J/cm(2)). Hologra phic grating formation was demonstrated as an example of application of thi s property, A sinusoidal,orating with 40-nm amplitude was easily fabricated on the surface of the polymer film by introducing two coherent laser beams . The main mechanism of grating formation in the copolymer was not mass tra nsport of copolymer chains due to pressure gradients but evaporation of the copolymer, Mass reduction associated with polymer evaporation was observed by means of the Quartz Crystal Microbalance (QCM) method. (C) 1998 Elsevie r Science B.V. All rights reserved.