This project has pushed the state of the art in various ways. The researchers have achieved conceptual breakthroughs along the lines discussed above. They have built experimental systems with unique capabilities. In turn, these capabilities have enabled them to discover intriguing phenomena emerging from strong light-matter interactions. Such phenomena are not only relevant to fundamental physics research, but also to optoelectronic technologies. Below we discuss a few highlights of these state-of-the-art achievements.
The conceptual breakthroughs the researchers have achieved relate to new ways of processing information in optical systems. For example, they have recently shown how the strong optical nonlinearities discussed above can be used to realize optical sensors with unprecedented precision and speed. In addition, the experimental setups they have built push the state of the art in at least two important ways. First, by making a tunable optical cavity inside a closed-cycle cryostat (allowing them to reach temperatures down to -269 C), they can control light-matter interactions with unprecedented precision, at low-temperatures, and without constantly consuming helium. This is a technologically important achievement with major implications for physics research. In particular, this setup has enabled them to progress beyond the state of the art in their field by discovering a new class of materials with exceptionally strong nonlinearity; these materials only have this nonlinearity at low temperatures.
Regarding the discovery of phenomena emerging from strong light-matter interactions, the researchers pushed the state of the art in a couple of ways. An important discovery thus far is that light can flow without friction, in a state known as superfluidity, even when the optical system in which this occurs is operated at room temperature. The paradigm by which they realized this effect is new, and the room-temperature operation of their system brings the physics of supercurrents a step closer to applications. Another highlight of this project is the discovery of strong nonlinearities in an important class of materials known as halide perovskites. Those nonlinearities enabled the researchers to demonstrate how to control the state of light in an all optical way. Via the nonlinearity, they also discovered an unexpected phase transition that reveals fascinating properties of halide perovskites. All these results are expect to stimulate further research and ideas for applications in optoelectronics and beyond.
