Son et lumière: from microphotonics to nanophononics

The field of nanophononics is a new emerging field which is based on the combination of recent progress in nanotechnology, photonics, and new experimental methods for accessing acoustic excitations of nanostructures in the GHz to THz frequency range. The engineering of acoustic excitations in solids, their coherent generation and control, and the development of novel acousto-optical devices like phonon microcavities and phononic crystals are the most prominent research objectives. New functionality with respect to acousto-optical devices will arise from tailoring the acoustic impedance of material on a nanometer scale with atomic monolayer precision similar to designed optic devices with well defined refractive indices. The combined control over electronic and vibronic degrees of freedom offers new routes for functionality on the nanoscale. Since the electronic, vibronic and photonic densities of state are strongly altered in low-dimensional systems, new interaction schemes arise which have to be understood. For the investigation of dynamical excitations in such new structures new methods have evolved - mostly based on femtosecond laser sources - which have to be further developed to yield improved sensitivity towards acoustic excitation in nanostructures. All these recent developments in material design, nanotechnology and femtosecond to picosecond characterization methods have opened promising potentialities for coherent phonon generation, stimulation and manipulation, tailoring of phonon lifetimes, in phonon cavities as well as in other phonon multilayer devices based on acoustic impedance engineering. The aim of this school is:

• To put together different scientific communities working on acoustic excitations in solids, mainly from the optical and the acoustical point of view, communities which usually attend separate conferences and often do not share a common language.
• To provide in-depth tutorial lectures (typically 4 to 6 hours) at the postgraduate/postdoctoral level covering basic topics in the field, i.e. investigation methods (femtosecond time-resolved, static light scattering, etc.) calculation methods for acoustic band structures (transfer matrix, first principles,…), introduction to classical and innovative acoustic and acousto-optic devices (surface waves, phonon lasers, phononic crystals) as well as seminars on various recent developments.
• To stimulate discussions on how to combine the newly developed acoustic devices with other phonon systems and materials (oxides, piezoelectrics, etc.) to generate new functionalities for phonon physics and applications.