Periodic Reporting for period 3 - SCORPION (Strongly CORrelated Polaritons In Optoelectronic Nanostructures)
Reporting period: 2023-01-01 to 2024-06-30
The transport of energy and information in light and matter underlies numerous technologies and even our existence. Research in this ERC-funded project is driven by the conviction that the most effective mechanisms for energy and information flow are still poorly understood or unknown. Consider, for example, that humanity’s light-based technologies generally avoid nonlinearity, dissipation, and noise. In contrast, certain biological systems can transport energy with extraordinarily high efficiency while being nonlinear, lossy, and strongly influenced by noise. Indeed, a combination of losing strategies becomes a winning strategy according to Parrondo’s paradox in game theory.
Motivated by the above recognition, the group implementing this action investigates (experimentally and theoretically) optical systems where nonlinearity, loss, and noise, can synergistically enhance the transport of energy and information in light. The typical system they study is an optical cavity formed by two mirrors. The mirrors are roughly a micrometer apart and face each other. Light can bounce back and forth between the two mirrors thousands of times. Moreover, in between the mirrors, they place materials which can interact strongly with the trapped light. The result is a hybrid state called ‘polariton’, which is part light and part matter. It turns out that these polaritons have very special properties which are ideally suited for enhancing the flow of energy and information. Realizing such an enhanced energy transport in polariton systems is precisely one of the goals of this project.
Overall, the project has a twofold objective. On one hand, the researchers aim to uncover and understand new mechanisms which can enhance the transport of energy in light and matter. For example, they investigate whether and how light-matter interactions in cavities can modify the electrical conductivity of materials. The researchers have also discovered that, under certain conditions for the matter inside the cavity, light can flow without resistance. On the other hand, the researchers aim to explore how these new mechanisms can be utilized to improve information processing in optoelectronic devices. Example of optoelectronic information-processing devices of interest include sensors and optical computers processing information in unconventional ways assisted by nonlinearity, loss, and noise.
Motivated by the above recognition, the group implementing this action investigates (experimentally and theoretically) optical systems where nonlinearity, loss, and noise, can synergistically enhance the transport of energy and information in light. The typical system they study is an optical cavity formed by two mirrors. The mirrors are roughly a micrometer apart and face each other. Light can bounce back and forth between the two mirrors thousands of times. Moreover, in between the mirrors, they place materials which can interact strongly with the trapped light. The result is a hybrid state called ‘polariton’, which is part light and part matter. It turns out that these polaritons have very special properties which are ideally suited for enhancing the flow of energy and information. Realizing such an enhanced energy transport in polariton systems is precisely one of the goals of this project.
Overall, the project has a twofold objective. On one hand, the researchers aim to uncover and understand new mechanisms which can enhance the transport of energy in light and matter. For example, they investigate whether and how light-matter interactions in cavities can modify the electrical conductivity of materials. The researchers have also discovered that, under certain conditions for the matter inside the cavity, light can flow without resistance. On the other hand, the researchers aim to explore how these new mechanisms can be utilized to improve information processing in optoelectronic devices. Example of optoelectronic information-processing devices of interest include sensors and optical computers processing information in unconventional ways assisted by nonlinearity, loss, and noise.
This project investigates emergent phenomena in systems where light and matter interact strongly. To make this possible, the researchers have developed worldwide unique experimental setups. Their setups enable them to precisely measure optical and electronic properties of nanoscale materials inside cavities, and to tune the strength of light-matter interactions in situ. Moreover, they have developed theoretical and numerical methods to describe the systems they study, and to predict fundamentally-interesting and technologically-relevant behavior.
One of the grand challenges in the field of the action is to realize sufficiently strong optical nonlinearities allowing light to be controlled with light in arbitrary ways. Half-way through the project, the researchers have already realized such strong nonlinearities in novel material systems. This has only been possible thanks to the unique experimental platform the researchers have developed. These recently-discovered nonlinearities have allowed the researchers to, for example, observe frictionless flow of light, and to discover emergent phenomena about the direction of information flow in complex systems. The researchers have also discovered important aspects about the characterization of polariton systems that have gone unnoticed for many years, thereby pushing the state of the art of the field. In addition, the researchers have theoretically demonstrated information-processing optical devices based on their nonlinear system. Finally, the researchers have invested significant efforts in developing a setup that can measure the electrical conductivity of materials inside tunable optical cavities. This last setup became functional very recently, and results are expected in the remainder of the project.
The researchers have already published many of the results mentioned above (and others omitted for brevity) in leading peer-reviewed scientific journals. Several other manuscripts are under preparation. In addition, the researchers have presented (and will continue to do so) several of their results at world-leading international scientific conferences and workshops.
One of the grand challenges in the field of the action is to realize sufficiently strong optical nonlinearities allowing light to be controlled with light in arbitrary ways. Half-way through the project, the researchers have already realized such strong nonlinearities in novel material systems. This has only been possible thanks to the unique experimental platform the researchers have developed. These recently-discovered nonlinearities have allowed the researchers to, for example, observe frictionless flow of light, and to discover emergent phenomena about the direction of information flow in complex systems. The researchers have also discovered important aspects about the characterization of polariton systems that have gone unnoticed for many years, thereby pushing the state of the art of the field. In addition, the researchers have theoretically demonstrated information-processing optical devices based on their nonlinear system. Finally, the researchers have invested significant efforts in developing a setup that can measure the electrical conductivity of materials inside tunable optical cavities. This last setup became functional very recently, and results are expected in the remainder of the project.
The researchers have already published many of the results mentioned above (and others omitted for brevity) in leading peer-reviewed scientific journals. Several other manuscripts are under preparation. In addition, the researchers have presented (and will continue to do so) several of their results at world-leading international scientific conferences and workshops.
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. Another unique aspect of the researchers’ setups is that they can measure extremely small electrical currents with micrometer scale precision, all while controlling the strength of light-matter interactions in their system. This capability already goes beyond the state of the art in the field, and important scientific results thanks to this capability are expected to arrive in the remainder of the project.
Finally, with regards to the discovery of phenomena emerging from strong light-matter interactions, the researchers have already gone beyond the state of the art in a couple of ways, and are expecting to publish additional breakthrough results soon. 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. In the future, the researchers will further explore their recently-discovered class of highly-nonlinear materials, and they aim to uncover possible signatures of electrical current enhancements in cavity materials. On this last point, there is an important on-going debate in the community on whether such effects are possible or not. Thus, while the outcome of their rigorous experiments remains unknown, its publication will push the state of the art. Even if no electrical current enhancement is achieved by optical means, the negative result itself will go beyond the state of the art by providing evidence for the lack of such effect.
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. Another unique aspect of the researchers’ setups is that they can measure extremely small electrical currents with micrometer scale precision, all while controlling the strength of light-matter interactions in their system. This capability already goes beyond the state of the art in the field, and important scientific results thanks to this capability are expected to arrive in the remainder of the project.
Finally, with regards to the discovery of phenomena emerging from strong light-matter interactions, the researchers have already gone beyond the state of the art in a couple of ways, and are expecting to publish additional breakthrough results soon. 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. In the future, the researchers will further explore their recently-discovered class of highly-nonlinear materials, and they aim to uncover possible signatures of electrical current enhancements in cavity materials. On this last point, there is an important on-going debate in the community on whether such effects are possible or not. Thus, while the outcome of their rigorous experiments remains unknown, its publication will push the state of the art. Even if no electrical current enhancement is achieved by optical means, the negative result itself will go beyond the state of the art by providing evidence for the lack of such effect.