Tunable Exciton-Driven Photoelasticity in 2D Material Acoustic Cavities.

While coupling between optical, electronic, and mechanical domains is paramount for high-frequency acoustic devices, materials that offer tunability in the degree of such coupling can be crucially enabling in expanding device functionality. Here, we show that the interaction of photons with coherent acoustic phonons confined in 2D layered semiconducting cavities can be controlled through either modifying the material state via a thermally induced electronic bandgap shift (EBS) or altering the polarization state of the incoming photons when optical birefringence is present in the cavity. We demonstrate temperature-driven EBS as an effective tool to engineer the WSe cavity readout as it allows one to sweep the excitonic energy relative to a chosen probe wavelength.

Complex Systems in Phase Space.

The continued reduction of semiconductor device feature sizes towards the single-digit nanometer regime involves a variety of quantum effects. Modeling quantum effects in phase space in terms of the Wigner transport equation has evolved to be a very effective approach to describe such scaled down complex systems, accounting from full quantum processes to dissipation dominated transport regimes including transients. Here, we discuss the challanges, myths, and opportunities that arise in the study of these complex systems, and particularly the advantages of using phase space notions.