Broken light symmetry experiment

Optical dielectric ring resonators manipulate, what ever are lightwaves, to instantly change its polarisation and stop time reversal symmetry.

What is light actually made of, what are its properties?

National Physical Laboratory's (NPL) researchers investigated how light can be controlled in an optical ring resonator, a tiny device that can store extremely high light intensities. Just as certain 'whispers' can travel around a whispering gallery and be heard the other side, in an optical ring resonator wavelengths of light resonate around the device ...

For instance, usually light will obey what is known as time reversal symmetry, meaning that if time is reversed, light should travel back to its origin. However, as this research shows, at high light intensities this symmetry is broken within optical ring resonators. Francois Copie, scientist on the project explains: When seeding the ring resonator with short pulses, the circulating pulses within the resonator will either arrive before or after the seed pulse but never at the same time ...

The research also showed that light can spontaneously change its polarisation in ring resonators. This is as if a guitar string was initially plucked in the vertical direction but suddenly starts to vibrate either in a clockwise or an anticlockwise circular motion.
Scientists discover new ways to twist and shift light | Phys.org

dielectric Optical ring resonators

In this work we study for the first time the interplay of two types of spontaneous symmetry breaking that can occur simultaneously in optical ring resonators. Specifically we investigate a ring resonator that is synchronously pumped with short pulses of light.

In this system we numerically study the interplay and transition between regimes of temporal symmetry breaking (in which pulses in the resonator either run ahead or behind the seed pulses) and polarization symmetry breaking (in which the resonator spontaneously generates elliptically polarized light out of linearly polarized seed pulses). We find ranges of pump parameters for which each symmetry breaking can be independently observed, but also a regime in which a dynamical interplay takes place.
Interplay of Polarization and Time-Reversal Symmetry Breaking in Synchronously Pumped Ring Resonators