Optical pump wavelength dependence in visible-pump visible-probe spectroscopy of noble metals

ORAL

Abstract

We have developed a femtosecond visible-pump visible-probe reflectometer with individually tunable pump and probe photon energies. The spectrometer has been used to study optically thick films of the noble metals Au and Cu over a wide variety of pump fluences and photon energies. Through comparison between experimental measurements and two-temperature model (TTM) simulations, we estimate an electron-phonon coupling constant, $g$, of $2.37 \pm 0.11 \times 10^{16}$ Wm$^{-3}$K$^{-1}$ for Au and $1.19 \pm 0.13 \times 10^{17}$ Wm$^{-3}$K$^{-1}$ for Cu, consistent with previous studies. The variation of the optical pump parameters allows a more accurate determination of the electron-phonon coupling constant. The relaxation rate, $\tau$, of the thermally excited electrons is shown to be strongly dependent on the peak electron temperature of the excited sample, and only weakly dependent on the pump photon energy. The static dielectric constant is found to significantly underestimate the dependence of the differential reflectivity on the pump photon energy.

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Authors

  • Derek G. Sahota

    Department of Physics, Simon Fraser University

  • C. Andreoiu

    University of Washington, Centre for Organic Photonics and Electronics, School of Chemistry and Molecular Biosciences, University of Queensland, Centre for Organic Photonics and Electronics, School of Mathematics and Physics, University of Queensland, Department of Physics, Simon Fraser University, Dalhousie University, Faculty of Mathematics, University of Waterloo, Department of Physics, McMaster University, SLAC National Accelerator Laboratory, Stanford University, Stanford University, IFW-Dresden, Northern Illinois University, University of British Columbia, University of Michigan, Simon Fraser University, Institute for Quantum Computing, University of Waterloo, Washington State University, The University of British Columbia, The Weizmann Institute of Science, Oregon State University, University of Massachusetts Lowell, Aixtron Ltd., Cornell University, TRIUMF, Society of Physics Students, Western Washington University, Department of Physics and Astronomy, Washington State University, University of Portland, Pacific University, University of Idaho, Department of Physics, University of Washington, Emory University, SFU, Arizona State University, Research Centre J\"ulich, University of Victoria, EPM, \'Ecole Polytechnique de Montr\'eal (EPM), Technical U of Denmark, Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Department of Physics, Portland State University, Portland, OR 97201, Department of Physics, Oregon State University, Corvallis, OR 97331, Department of Physics, Cornell University, Ithaca, NY 14853, Linfield College, Portland State University, University of British Columbia Physics and Astronomy, University of British Columbia Chemistry, Max Planck Institute for Polymer Research, Simon Fraser, Los Alamos National Lab, Los Alamos, McGill University, Los Alamos National Laboratory, University of Cambridge, CSNSM-IN2P3-CNRS, University of Manitobia, Univ. of British Columbia and TRIUMF, Ruprecht-Karls-Universitat and MPI and TRIUMF, Westfaelische Wilhelms-Universitaet, Univ. of Manitoba and TRIUMF, Tenische Universitaet Muenchen and TRIUMF, Simon Fraser Univ. and TRIUMF, University of British Columbia, TRIUMF, Ruprecht-Karls-Universit\"at Heidelberg, Max Planck Institute, TRIUMF, Westf\"alische Wilhelms-Universit\"at, TRIUMF, Johannes Gutenberg-Universit\"at Mainz, Ruprecht-Karls-Universit\"at Heidelberg, Univerity of Manitoba, TRIUMF, Simon Fraser University, TRIUMF, TRIUMF \& University of Manitoba, College of William and Mary, Universidad Autonoma de San Luis Potosi, University of Maryland, University of Manitoba, UBC, Texas A\&M, University of Kentucky, Georgia Institute of Technology, University of Guelph, St. Mary's University

  • C. Andreoiu

    University of Washington, Centre for Organic Photonics and Electronics, School of Chemistry and Molecular Biosciences, University of Queensland, Centre for Organic Photonics and Electronics, School of Mathematics and Physics, University of Queensland, Department of Physics, Simon Fraser University, Dalhousie University, Faculty of Mathematics, University of Waterloo, Department of Physics, McMaster University, SLAC National Accelerator Laboratory, Stanford University, Stanford University, IFW-Dresden, Northern Illinois University, University of British Columbia, University of Michigan, Simon Fraser University, Institute for Quantum Computing, University of Waterloo, Washington State University, The University of British Columbia, The Weizmann Institute of Science, Oregon State University, University of Massachusetts Lowell, Aixtron Ltd., Cornell University, TRIUMF, Society of Physics Students, Western Washington University, Department of Physics and Astronomy, Washington State University, University of Portland, Pacific University, University of Idaho, Department of Physics, University of Washington, Emory University, SFU, Arizona State University, Research Centre J\"ulich, University of Victoria, EPM, \'Ecole Polytechnique de Montr\'eal (EPM), Technical U of Denmark, Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, Department of Physics, Portland State University, Portland, OR 97201, Department of Physics, Oregon State University, Corvallis, OR 97331, Department of Physics, Cornell University, Ithaca, NY 14853, Linfield College, Portland State University, University of British Columbia Physics and Astronomy, University of British Columbia Chemistry, Max Planck Institute for Polymer Research, Simon Fraser, Los Alamos National Lab, Los Alamos, McGill University, Los Alamos National Laboratory, University of Cambridge, CSNSM-IN2P3-CNRS, University of Manitobia, Univ. of British Columbia and TRIUMF, Ruprecht-Karls-Universitat and MPI and TRIUMF, Westfaelische Wilhelms-Universitaet, Univ. of Manitoba and TRIUMF, Tenische Universitaet Muenchen and TRIUMF, Simon Fraser Univ. and TRIUMF, University of British Columbia, TRIUMF, Ruprecht-Karls-Universit\"at Heidelberg, Max Planck Institute, TRIUMF, Westf\"alische Wilhelms-Universit\"at, TRIUMF, Johannes Gutenberg-Universit\"at Mainz, Ruprecht-Karls-Universit\"at Heidelberg, Univerity of Manitoba, TRIUMF, Simon Fraser University, TRIUMF, TRIUMF \& University of Manitoba, College of William and Mary, Universidad Autonoma de San Luis Potosi, University of Maryland, University of Manitoba, UBC, Texas A\&M, University of Kentucky, Georgia Institute of Technology, University of Guelph, St. Mary's University

  • J. Steven Dodge

    Simon Fraser University, Department of Physics, Simon Fraser University