title: Ultrafast electron and phonon response of oriented and diameter-controlled germanium nanowire arrays.
abstract: Carrier and phonon dynamics in dense arrays of aligned, single-crystal Ge nanowires (NWs) of controlled diameter are investigated by ultrafast optical pump-probe measurements, effective medium calculations, and elasticity analysis. Both a pronounced induced absorption and the amplitude and spectral range of Fabry-Perot oscillations observed in the probe signal are predicted for the NW array/air metamaterial by effective medium calculations. Detected temporal oscillations of reflectivity are consistent with excitation of radial breathing mode acoustic phonons by the intense pump pulse.
authors.affiliation: Department of Applied Physics and §Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Yanying
authors.initials: Y
authors.lastname: Li
authors.forename: Raphael
authors.initials: R
authors.lastname: Clady
authors.forename: Junghyun
authors.initials: J
authors.lastname: Park
authors.forename: Shruti V
authors.initials: SV
authors.lastname: Thombare
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Schmidt
authors.forename: Mark L
authors.initials: ML
authors.lastname: Brongersma
authors.forename: Paul C
authors.initials: PC
authors.lastname: McIntyre