Picosecond ultrasonics is a powerful tool for nanoscale metrology, giving access to dimensions and mechanical, thermal, optical properties of nanomaterials. By monitoring the temporal evolution interaction light with coherent acoustic phonons, also known as Brillouin oscillations, phonon lifetime absorption can be measured. However, extraction these quantities inaccurate due common assumption i...

The calling song of an undescribed Meconematinae katydid (Tettigoniidae) from South America consists of trains of short, separated pure-tone sound pulses at 129 kHz (the highest calling note produced by an Arthropod). Paradoxically, these extremely high-frequency sound waves are produced by a low-velocity movement of the stridulatory forewings. Sound production during a wing stroke is pulsed, b...

The suppression of order parameter fluctuations at the boundaries causes the ultrasonic attenuation near the superfluid transition to be lowered below the bulk value . We calculate explicitly the first deviation from the bulk value for temperatures above the lambda point . This deviation is significantly larger than for static quantities like the thermodynamic specific heat or other transport p...

Cross fertilization between the quantitative nondestructive evaluation (QNDE) community and the diagnostic medicine community in the area of ultrasonics represents an attractive but challengin~ goal. High resolution, real-time ultrasonic imaging is routinely available not only in major medical centers but even in modest community hospitals. However, quantitative ultrasonic evaluation based on t...

A picosecond ultrasonics technique has been used to detect interfacial fluorocarbon (CF,) layers as thin as 0.5 nm between aluminum and silicon. The presence of the CF, material reduces acoustic damping and heat loss from the Al film into the Si substrate. This provides a means for noninvasive identification of organic/polymeric contaminants at the buried interface and potentially for character...