Coherent phonon optics in a chip with an electrically controlled active device.

Area of Science:

• Solid-state physics
• Acoustics
• Nanotechnology

Background:

• Phonon optics manipulates high-frequency acoustic waves (phonons) in solids, analogous to light optics.
• Current phonon optics relies on passive manipulation, lacking external control over phonon beams.
• Terahertz and sub-terahertz phonon experiments offer potential for acoustics, imaging, and heat transport innovations.

Purpose of the Study:

• To develop and demonstrate active control in phonon optics.
• To enable external manipulation of coherent phonon beams using electrical bias.
• To expand the applications of phononics at the nanoscale.

Main Methods:

• Fabrication of a phononic chip integrating a coherent phonon generator (378 GHz), detector, and an active semiconductor superlattice.
• Insertion of the active layer with electrical contacts into the phonon propagation path.
• Experimental application of external electrical bias to the active layer.

Main Results:

• Successful demonstration of external electrical bias modulating the coherent phonon flux.
• Validation of active control capabilities within the fabricated phononic chip.
• Observation of controlled manipulation of terahertz phonon beams.

Conclusions:

• The developed phononic chip enables active control of phonon optics for the first time.
• External electrical control significantly broadens the potential applications of phononics.
• This work advances the field towards sophisticated nanoscale acoustic devices.