title: Thermoreflectance of metal transducers for optical pump-probe studies of thermal properties.
abstract: We report measurements of the temperature dependence of the optical reflectivity, dR/dT of fifteen metallic elements at a wavelength of λ = 1.03 μm by time-domain thermoreflectance (TDTR); and the thermoreflectance of thin-films of Pt, Ta, Al, Au, SrRuO(3), and LaNiO(3) over the wavelength range 0.4 < λ < 1.6 μm using variable angle spectroscopic ellipsometry. At λ = 1.03 μm, Al, Ta, Re, Ru, have high values of thermoreflectance, dR/dT > 6∙10(-5) K(-1), and are good choices as optical transducers for TDTR experiments using a Yb:fiber laser oscillator. If low optical reflectivity and the associated high degree of steady-state heating are not a concern, LaNiO(3) provides an exceptionally sensitive thermometer in the infrared; (1/R)(dR/dT) > 2.5∙10(-4) K(-1) in the wavelength range 0.85 < λ < 1.3 μm. This compilation of data will assist in the design and interpretation of optical pump-probe studies of thermal properties.
authors.affiliation: Department of Materials Science, and Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA. wilson81@illinois.edu
authors.forename: R B
authors.initials: RB
authors.lastname: Wilson
authors.forename: Brent A
authors.initials: BA
authors.lastname: Apgar
authors.forename: Lane W
authors.initials: LW
authors.lastname: Martin
authors.forename: David G
authors.initials: DG
authors.lastname: Cahill
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D007909:Lenses; D008027:Light; D008670:Metals / Q000737:chemistry*; D012542:Scattering, Radiation; D013696:Temperature; D013814:Thermal Conductivity; D014159:Transducers
chemical_list: D008670:Metals