SCIENTIFIC EDUCATIONAL CENTER science idea

A new study by a team of researchers at City College of New York has discovered a new way of combining two different states of matter. For the first time, topological photons - light - have been combined with lattice vibrations, also known as phonons, to reliably and controllably control their propagation.
The study used topological photonics - a new direction in photonics, which uses the fundamental ideas of the mathematical field of topology about conserved quantities - topological invariants that remain constant when changing parts of a geometric object under continuous deformations.
One of the simplest examples of such invariants is the number of holes, which, for example, makes a donut and a mug topologically equivalent.
Topological properties endow photons with helicity as photons rotate during propagation, resulting in unique and unexpected characteristics such as defect resistance and unidirectional propagation along interfaces between topologically different materials. By interacting with vibrations in crystals, these spiral photons can then be used to transmit infrared light along with the vibrations.
This work has wide implications, in particular, it allows researchers to develop Raman spectroscopy, which is used to determine the vibrational modes of molecules. The study also holds promise for vibrational spectroscopy, also known as infrared spectroscopy, which measures the interaction of infrared radiation with matter through absorption, emission, or reflection. This can then be used to study, identify and characterize chemicals.
“We have combined spiral photons with lattice vibrations in hexagonal boron nitride to create a new hybrid matter called phonon polaritons,” said Alexander Khanikayev, lead author and physicist at the CCNY School of Engineering in Grove. “It's half light, half vibration. Since infrared light and lattice vibrations are associated with heat, we have created new channels for the distribution of light and heat together. As a rule, the vibrations of the lattice are very difficult to control, and it was impossible to direct them around defects and sharp corners in the past ”.
The new methodology could also implement directional radiant heat transfer, a form of energy transfer during which heat is dissipated by electromagnetic waves.
“We can create channels of arbitrary shape for this form of hybrid excitations of light and matter, which will be guided in the two-dimensional material we have created,” added Sriram Guddala, the first author of the work. “This method also allows us to switch the direction of propagation of oscillations along these channels, forward or backward, simply by switching the polarization direction of the incident laser beam. Interestingly, as the phonon polaritons propagate, the vibrations also rotate with the electric field. This is a completely new way of directing and rotating the vibrations of the lattice, which also makes them spiral. "
The study was published in the journal Science.
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