Optical techniques for pump-probe magnetic measurements and nanoimaging of biological samples Antonio Cricenti • Stefano Colonna • Ernesto Placidi • Marco Luce • Jingbo Qi • Norman H. Tolk • Giorgio Margaritondo Received: 21 July 2011 / Accepted: 25 September 2011 / Published online: 13 October 2011 Ó Springer-Verlag 2011 Abstract Fast pump-probe magneto-optic techniques have been used to investigate the hot carrier and magnetization dynamics in InAs nanostructures deposited on GaAs(001). From these time resolved reflectivity and Faraday rotation measurements, different dynamics responses were found for samples containing different InAs thicknesses. We also present some results of near field spectroscopy with infrared radiation emitted by a free electron laser to investigate biological samples. The local reflectivity revealed features as a function of photon energy that were not present in the corresponding shear-force (topol- ogy) images and were due to localized changes in the bulk properties of the sample. Keywords Pump-probe Á Magnetic materials Á Infrared optical nanospectroscopy Á Biological cells 1 Introduction Optical techniques can investigate fast physical processes in the sub-picosecond time-scale and structural properties at the nanometer resolution (below the diffraction limit of the conventional optics) with applications in the field of material science and biophysics. Invited Contribution presented to the 1st Bilateral Italian Chinese Workshop on Synchrotron radiation time resolved concurrent experiments: advantages and future applications. A new Italian route to China (Shanghai, November 11, 2010). Each article of this volume was accepted after a peer review procedure. A. Cricenti (&) Á S. Colonna Á E. Placidi Á M. Luce Istituto di Struttura della Materia, CNR, Via Fosso del Cavaliere 100, 00133 Rome, Italy e-mail: cricenti@ism.cnr.it A. Cricenti Á J. Qi Á N. H. Tolk Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 31235, USA G. Margaritondo Institute of Physics of Biological Systems, E ´ cole Polytechnique Fe ´de ´rale, 1015 Lausanne, Switzerland 123 Rend. Fis. Acc. Lincei (2011) 22 (Suppl 1):S49–S57 DOI 10.1007/s12210-011-0148-y