We have used a picosecond optical technique to measure the attenuation ␣ of longitudinal-acoustic phonons in several disordered solids. We find a universal ␣ϳ 2 behavior for frequencies up to 320 GHz and for temperatures between 80 and 300 K. Within this temperature range the phonon attenuation increases by a factor of between 2 and 3 with increasing temperature for the amorphous polymers poly͑methyl methacrylate͒, poly͑styrene͒, and poly͑ethyl methacrylate͒, and for the metallic glass TiNi. We discuss our results in relation to current theories of high-frequency vibrations in glasses and thermal conduction. ͓S0163-1829͑96͒04325-1͔

A picosecond pump-probe technique is used to measure the room-temperature thermal conductivity κ and longitudinal sound velocity cl of amorphous diamond (a-D) and diamondlike carbon (DLC) thin films. Both κ and cl were found to decrease with film hydrogen content. Depending on the film deposition technique, κ is in the range 5–10×10−2 W cm−1 K−1 for a-D, and 3–10×10−3 W cm−1 K−1 for DLC. Values of cl were found to be in the range 14–18×105 cm s−1 for a-D, and 6–9×105 cm s−1 for DLC.

No abstract