Morten Willatzen

TL;DR: In this article, a quantitative discussion of the combined influence of three electro-mechanical effects (i.e., piezoelectricity, flexo-cylindricality, and electrostriction) in solids is provided for acoustic absorption and gain.

TL;DR: It is found that nonlinear effects are not important at high frequencies (1 MHz) subject to high-input voltages, but they become important under high-voltage and off-resonance conditions.

TL;DR: In this paper, the analysis is extended theoretically to include cases where a background flow in a periodic structure is maintained and it is shown that acoustic waves couple to the group velocities only if the (acoustic) wave vector has a component along the background flow velocity direction.

TL;DR: In this article, a simple experimental technique based on diffraction for determining the complex refractive index of metamaterials is presented, and the authors demonstrate it with metammaterials that consist of detuned electrical dipoles (DEDs).

TL;DR: In this paper, the authors demonstrate a significantly improved optoelectronic performance due to strain in the THz-infrared spectrum using a first-principles Hamiltonian, incorporating all symmetry-allowed terms to second order in the wave vector, first order in strain, and of order $\ensuremath{\epsilon}k", and demonstrate that the directional average of the absorbance always increases with strain.