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DF: Dielektrische Festkörper

DF 5: Glass I (together with division ‘Dynamics and Statistical Physics’ [DY])

DF 5.7: Vortrag

Dienstag, 28. März 2006, 11:50–12:10, M{\"U}L Elch

Optical Properties of Colloidal Suspension of Silver Nanoparticles* — •Helge A. Eggert¹, Jim R. Adleman², Demetri Psaltis², and Karsten Buse¹ — ¹Institute of Physics, University of Bonn, Wegelerstr. 8, 53115 Bonn — ²Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125

Colloidal suspensions of silver nanoparticles are an interesting optical material because of homogeneity, stability, and tailored absorption properties. To understand the thermal and nonlinear-optical response, holographic gratings are recorded in such colloidal suspensions of silver nanoparticles utilizing interfering nanosecond pulses (wavlength λ=532 nm, puls duration 6 ns, intensity 10 GW/m²). The diffraction efficiency is measured with continuous-wave light (λ=633 nm). An instantaneous response together with a longer lasting but also transient grating are observed: The nanoparticles absorb the pump light and heat up, which yields a response on the time scale of the laser pulse. Heat is transferred to the solvent, and a delayed thermal grating appears. The final decay time constant of this grating depends quadratically on the period length of the interference pattern and has a typical value of 1 µs for grating spacings of several micrometers.

*Financial support by the DFG (BU 913/17) and by the Deutsche Telekom AG is gratefully acknowledged.

Prize Talk
The prize talk (Max-Planck-Medaille) by Prof. Götze takes place Tuesday, 13:15, HSZ 04. The title of the talk is “Glassy Relaxation: a Paradigm for Condensed-Matter Dynamics”. See the plenary section for the abstract.