TY - JOUR T1 - Coherent vibrational oscillation in gold prismatic monolayer periodic nanoparticle arrays JF - Nano Letters Y1 - 2004 A1 - Huang, Wenyu A1 - Qian, Wei A1 - El-Sayed, Mostafa A AB - We studied the ultrafast laser-induced coherent phonon oscillation in prismatic shaped gold nanoparticles assembled in monolayer periodic arrays by using the nanosphere lithographic technique. The amplitude and phase of the oscillation observed by ultrafast pump-probe transient spectroscopy is monitored as the wavelength of the dipolar surface plasmon absorption decreases. At a certain wavelength, the oscillation could not be observed. As the monitoring wavelength decreases further, the sign of the amplitude changes. From the wavelength at which the oscillation is not detected, the dependence of the absorption maxima on the size of the nanoparticles, the changes in the nanoparticle size are estimated during its oscillation. This large change in the size of the prismatic nanoparticle compared to the small change reported previously for the nanosphere oscillations is discussed. VL - 4 SN - 1530-6984 N1 - Huang, WY Qian, W El-Sayed, MA M3 - 10.1021/nl048875p ER -