Tricomi beams show promise for optical communication through humid marine environments

Light beams that refuse to spread as they travel through space have long intrigued physicists and engineers. These diffraction-free beams possess a peculiar trick: when obstacles scatter them, they can reconstruct themselves, healing the damage as they propagate forward. This self-healing property, combined with their resistance to spreading, makes them attractive for sending signals through the atmosphere, mapping terrain from above, and detecting distant objects. But most of what we know about these beams comes from laboratory conditions. The real world—particularly the humid, salt-laden air above oceans—presents a far messier problem.

Tricomi beams represent a newer entry in the family of non-diffracting light structures. Unlike their better-studied cousins, Tricomi beams have remained largely theoretical when it comes to their behavior in marine environments, where salt aerosols suspended in moisture-heavy air scatter and distort electromagnetic waves. A research team has now conducted the first comprehensive theoretical examination of how these beams interact with the spherical particles that make up sea spray and maritime haze. Using generalized Lorenz–Mie theory—a mathematical framework for calculating how light scatters off spheres—the researchers computed how Tricomi beams behave when they encounter marine aerosols of varying sizes and compositions.

The findings reveal that Tricomi beams offer a level of control unavailable with conventional light. By adjusting the beam's topological charge (a measure of its spiral structure), its asymmetry parameters, and its half-cone angle, researchers can fine-tune how much light scatters and how the scattered light's polarization—the orientation of its oscillating electric field—changes in response. The larger the aerosol particles, the more intense the scattering becomes. Increasing the beam's topological charge produces the same effect. But humidity, which alters both the size and the refractive index of salt particles in the air, introduces substantial shifts in how the beam scatters and how its polarization state transforms. These shifts are not random noise; they follow predictable patterns that depend on the specific humidity conditions.

The practical implications point in two directions. First, optical communication systems operating over water or through coastal fog could exploit Tricomi beams' tunability to maintain signal integrity despite the presence of aerosols. Rather than fighting against scattering, engineers could adjust beam parameters to work with it, potentially achieving more robust links than conventional laser-based systems allow. Second, the polarization changes induced by marine aerosols could become a diagnostic tool. By measuring how a Tricomi beam's polarization shifts after passing through humid air, instruments could infer properties of the aerosol population—particle size, salt concentration, humidity levels—without direct sampling.

The work remains theoretical, grounded in mathematical modeling rather than experimental demonstration. No prototype has yet transmitted data through actual sea spray, and the calculations assume idealized spherical particles, whereas real marine aerosols exhibit irregular shapes and complex internal structures. Still, the research establishes a foundation. It shows that Tricomi beams respond to maritime conditions in ways that can be predicted and controlled, opening a path toward practical systems that exploit these unusual light structures for communication and sensing in environments where conventional optics struggle.