Structures induced by irradiation of femto-second laser pulse in polymeric materials

We investigated the structures induced by irradiation of near-infrared femto-second laser pulse in various polymer materials; olefin gel, acrylic adhesive, poly(ether sulphone) (PES), poly(methyl methacrylate) (PMMA), polycarbonate (PC), and block copolymers of methyl-methacrylate and ethyl acrylate-butyl acrylate. Line irradiation that was performed by scanning laser spots in polymer bulk formed volcano-like upheaval structures on the surfaces of PES, PMMA, and PC, which have relatively high glass-transition temperatures (T-g's); on the other hand, cave or channel structures on the surfaces of olefin gel and acrylic adhesive have low T-g's. For the block copolymers containing both low and high T-g's, aggregation of the submicron scale deposit was induced in the polymer bulk. The submicron scale deposit may be reproduced structures after photodecomposition or photocrosslinking of polymer-chain components induced by multiphoton excitation with femto-second laser irradiation. This deposit aggregation with a stripelike structure had different optical properties from the un-irradiated region. These structures induced by irradiation of femto-second laser pulse might be applicable for optical devices such as diffraction grating and optical guide. (C) 2002 Wiley Periodicals, Inc.