Femtosecond laser-induced decomposition in triazenepolymer thin films J. Bonse a, * , S.M. Wiggins a , J. Solis a , T. Lippert b , H. Sturm c a Instituto de Optica, C.S.I.C., Serrano 121, E-28006 Madrid, Spain b Paul Scherrer Institut (PSI), CH-5232 Villigen, Switzerland c Project group ‘‘Nanoanalytics for Micro Systems Technology’’, Bundesanstalt fu ¨r Materialforschung und pru ¨fung (BAM), Unter den Eichen 87, D-12205 Berlin, Germany Available online 30 March 2005 Abstract The damage induced by ultrashort, 130 fs, near-infrared, 800 nm, Ti:sapphire laser pulses in 1 mm thick triazenepolymer films on glass substrates has been investigated. Real-time reflectivity measurements with a ps-resolution streak camera and a ns- resolution photodiode set-up have been performed to study in situ the structural transformation dynamics upon single-pulse excitation with laser fluences above the threshold of permanent damage. Scanning force microscopy has been used to probe ex situ the corresponding surface topography of the ablated spots. Modulated lateral force microscopy (M-LFM) has been applied to observe alterations of the local friction properties within and around the irradiated areas. # 2005 Elsevier B.V. All rights reserved. PACS: 52.38.Mf; 79.20.Ds Keywords: Laser-induced phase transitions; Triazenepolymer film; Femtosecond laser pulse irradiation; Time-resolved reflectivity measurements; Scanning force microscopy; Ablation; Damage 1. Introduction For more than two decades, the laser processing of polymers has been intensively studied, especially in the UV regime where many polymers of interest are highly absorbing [1–4]. One polymer group of particular interest is that of the triazenepolymers [5] which are photochemically very active upon UV irradiation and have superior ablation properties by irradiation at l = 308 nm [6]. In a previous study [7], we have investigated the behaviour of a triazenepolymer film upon irradiation with single ultrashort near-infrared, 800 nm, pulses that, due to their high intensities, may be an alternative way of structuring by means of multi-photon absorption in the material. That work mainly focused www.elsevier.com/locate/apsusc Applied Surface Science 248 (2005) 157–162 * Corresponding author. Tel.: +34 91 561 6800; fax: +34 91 564 5557. E-mail address: jbonse@io.cfmac.csic.es (J. Bonse). 0169-4332/$ – see front matter # 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2005.03.021