Nanophononics : a nonlinear battleground par excellence

Abstract

We briefly review the basic schemes for coherent optically driven sources of large amplitude acoustic pulses and large acoustic phonon populations down to the picosecond and submicron spatiotemporal scales; their beam directivity and monochromaticity can be comparable to that of optical pulses delivered by lasers and other intense coherent optical sources and are being exploited in a number of powerful diagnostic techniques and phononic devices where in addition confinement can substantially improve their performances.

Here we single out and put particular emphasis on the passive photothermal schemes in metal and semiconductor nanostructures for generation of coherent intense acoustic pulses and sketch the underlying physical processes. We illustrate the present state of art with some examples from recent studies for soliton propagation and attempts for saser (sound amplification by stimulated emission of radiation) operation, phononic gratings and microcavities and older ones on parametric phonon breakdown.