Phonon nanocapacitor for storage and lasing of terahertz lattice waves

TL;DR

This paper presents a new ultra-compact phonon nanocapacitor capable of storing and lasing coherent terahertz lattice waves, with potential applications in THz technology and phonon-based devices.

Contribution

It introduces a novel atomic-scale semiconductor metamaterial nanocapacitor for coherent phonon storage and lasing, including mechanisms for multi-color operation and strain-controlled discharge.

Findings

Nanocapacitor stores THz lattice waves effectively.

Enables one- and two-color phonon lasing.

Discharges via tunable strain to emit coherent THz beams.

Abstract

We introduce a novel ultra-compact nanocapacitor of coherent phonons formed by high-finesse interference mirrors based on atomic-scale semiconductor metamaterials. Our molecular dynamics simulations show that the nanocapacitor stores THz monochromatic lattice waves, which can be used for phonon lasing - the emission of coherent phonons. Either one- or two-color phonon lasing can be realized depending on the geometry of the nanodevice. The two color regimes of the capacitor originates from the distinct transmittance dependance on the phonon wave packet incident angle for the two phonon polarizations at their respective resonances. Phonon nanocapacitor can be charged by cooling the sample equilibrated at room temperature or by the pump-probe technique. The nanocapacitor can be discharged by applying tunable reversible strain, resulting in the emission of coherent THz acoustic beams.