Researchers announce photon-phonon breakthrough

Phys.org ^ | City College of New York

[BenLurkin]

For one of the first times, topological photons—light—has been combined with lattice vibrations, also known as phonons, to manipulate their propagation in a robust and controllable way.

"We coupled helical photons with lattice vibrations in hexagonal boron nitride, creating a new hybrid matter referred to as phonon-polaritons," said Alexander Khanikaev, lead author and physicist with affiliation in CCNY's Grove School of Engineering. "It is half light and half vibrations. Since infrared light and lattice vibrations are associated with heat, we created new channels for propagation of light and heat together. Typically, lattice vibrations are very hard to control, and guiding them around defects and sharp corners was impossible before."

The new methodology can also implement directional radiative heat transfer, a form of energy transfer during which heat is dissipated through electromagnetic waves.

"We can create channels of arbitrary shape for this form of hybrid light and matter excitations to be guided along within a two-dimensional material we created," added Dr. Sriram Guddala, postdoctoral researcher in Prof. Khanikaev's group and the first author of the manuscript. "This method also allows us to switch the direction of propagation of vibrations along these channels, forward or backward, simply by switching polarizations handedness of the incident laser beam. Interestingly, as the phonon-polaritons propagate, the vibrations also rotate along with the electric field. This is an entirely novel way of guiding and rotating lattice vibrations, which also makes them helical."

Entitled "Topological phonon-polariton funneling in midinfrared metasurfaces," the study appears in the journal Science.

[Celtic Conservative]

Phaser, anyone?

CC

[SunkenCiv]

[snip] A phonon is the quantum mechanical description of an elementary vibrational motion in which a lattice of atoms or molecules uniformly oscillates at a single frequency. In classical mechanics this designates a normal mode of vibration. [/snip]

https://en.wikipedia.org/wiki/Phonon

[Paal Gulli]

The “hexagonal boron nitride” (hBN) they used in this experiment is great stuff for D-I-Y slick-coated bullets, much better than the old stand-by, molybdenum misulfide (AKA Moly).