We report the application nondegenerate ultrafast midinfrared spectroscopy to investigate the acoustic phonon cooling process in epitaxial graphene. We show that the powerdependent experimental results match theoretical predictions of the low temperature acoustic cooling process. The hot phonon effect in acoustic phonon cooling is observed experimentally, and a deformation potential of 30 eV ca...

New results are presented for the degeneracy condition of elastic waves in anisotropic materials. The condition for the existence of acoustic axes involves a traceless symmetric third order tensor that must vanish identically. It is shown that all previous representations of the degeneracy condition follow from this acoustic axis tensor. The conditions for existence of acoustic axes in elastic ...

We present a new concept for waveguide acousto-optical devices based on coupled Mach–Zehnder interferometers driven by acoustic waves. These acousto-optical multiple interference devices use the periodic refractive index modulation induced by the acoustic wave to realize functionalities such as ON/OFF switching for an arbitrary time interval, as well as for efficient light modulation at high ha...

A hybrid-computing architecture consisting of a general purpose digital signal processor (DSP) closely coupled to a field-programmable gate array serving as a reconfigurable processor has been demonstrated as having great utility to collect, process, and report data from a sensor node containing acoustic and possibly other sensors. The computing architecture for microsensors (CAμS) was develope...

Previous work has shown the formation of solid particles into thin walls of specified shape using a resonant acoustic field in microgravity. Here these results are summarized, and extended to study the qualitative effects of liquid addition and melting/ solidification in the acoustic field. Pure liquid forms into sheets, even in the 1-g environment, due to the static pressure differences in the...