In two recent studies published in the journals Nature Communications and Science Advances , Antonio Ambrosio and his team at the Center for Nanoscience and Nanotechnology (CNST) at IIT Milan have introduced new materials in photonics and optoelectronics, and techniques for manipulating light in time.
According to Albert Einstein’s autobiography, the theory of relativity was born from his dream of a ray of light falling. From Newton to the present day, scientists have been fascinated by the physical properties of light, and their mastery has led to the creation of new technologies such as lasers, fiber optics, and quantum computers.
Antonio Ambrosio, Principal Investigator of the Vector Nanoimaging Laboratory and two-time European Research Council Award winner, specializes in the study of light control, its fundamental properties, and the potential applications of his research.
Ambrosio’s work introduces both new materials in photonics and optoelectronics, as well as techniques for controlling light in time dimensions related to the concept of space-time in Einstein’s general theory of relativity.
The first study is based on a novel idea: If a material can direct and change the physical properties of light while acting like a fluid that maintains its integrity, it could lead to advances in quantum technology, communications, ultra-high-resolution optical microscopy, and even solar energy.
Depending on how an object interacts with light, it can be brightly colored or almost invisible. Ambrosio and his team showed that visible light can be manipulated in this way by studying a crystal made of molybdenum, chlorine, and oxygen atoms (MoOCl₂).
The findings, published in the journal Nature Communications, open up new possibilities in the field of nanophotonics, which opens up the possibility of studying new, highly controlled physical phenomena at the nanoscale using light-matter interactions.
The key discovery was the discovery that visible light could be confined and transmitted through ultrathin crystals, just a few billionths of a meter thick, without relying on the traditional diffraction method of trapping light within a material.
This effect is caused by plasmon polarization, a hybrid wave of matter and radiation that is common in metals. Depending on how the material interacts with light, its optical properties change – it acts in one direction in a metal, and in a perpendicular direction in an insulator or dielectric medium.
The second study, published in the journal Science Advances, describes a method for studying and manipulating light on extremely short timescales, such as femtoseconds, or billionths of a second. The method changes the spatial properties of light, such as its shape and its temporal magnitude, without relying on external forces.
This technique exploits the natural relationship between the temporal frequency of an electromagnetic wave and its angular momentum – a property that defines how energy flows through space.
Ambrosio’s team introduced rapid modulation of the wave, creating pulse-like changes that altered its spatial and temporal distribution. This allowed them to achieve unprecedented results, including spiral orbits and self-acceleration of light.
This method eliminates the need for external forces and allows for rapid and precise control of light. This has potential applications in controlling nano- and microstructures, which are key elements of condensed matter physics, or in supporting ultrafast spectroscopy.
Journal reference:
Piccardo, M., et al . (2023) Broadband control of topological-spectral correlations in spatiotemporal radiation. Nature Photonics . doi.org/10.1038/s41566-023-01223-y.
Source:
Italian Institute of Technology
