Picosecond Ultrasonic and Heat Flow Measurements with Enhanced Sensitivity

T. J. Grimsley ； J. Ma ； Q. Miao ； A. V. Nurmikko ； H. J. Maris

《Chinese Journal of Physics》 49卷1期 (2011/02) Pp. 176-183

並列摘要

We report on two variations of the standard measurement technique used for making picosecond ultrasonic and heat flow measurements. In the first variation, a resonant optical cavity is produced above the surface of the sample. For a highly reflecting sample, this cavity enhances the fraction of the energy of the pump pulse that is absorbed by the sample, and also increases the change in the reflection of the probe pulse that results from the change in the optical constants of the sample. In the second variation, a transparent optical mask is placed just above the surface. This mask results in a periodic variation of the intensity of the pump and probe beams across the sample surface, and makes possible the study of lateral heat flow in thin films and nanostructures.