Science fiction is full of common tropes like the Cloak Of Invisibility in Harry Potter, where you can make something invisible. It sounds great, but it’s not using technology. While the obvious uses of espionage are obvious, there are many more.
It’s not surprising that engineers and scientists have been working hard on this topic. They have made much progress using molybdenum trioxide, metamaterials, HTMLscreens, and dielectric material to make invisible cloaks. This all boils down to controlling light properly. Moreover, innovation in this area can greatly enhance sensors, telecommunications and encryption.
Space is the ultimate frontier… The starship Enterprise continues its quest to explore the galaxy when all communication channels are suddenly cut off due to an impassable nebula. Star Trek’s iconic TV series has many episodes where the crew must ‘technically the tech’ and “science the science” within 45 minutes to escape this or another similar situation before the credits roll. Although they spent much longer in their laboratories, scientists from the University of Rostock were able to develop a new method for designing artificial materials that transmit light signals without distortions using precisely tuned energy flows.
“When light scatters in an inhomogeneous medium it causes scattering. This transforms a concentrated beam quickly into a diffuse glow. It is a phenomenon that is well-known to us all from autumn fog and summer clouds alike,” Professor Alexander Szameit of the University of Rostock describes as the beginning point of his research. It is the material’s microscopic density that determines the details of scattering. Szameit says, “The basic idea of induced transparency, as it is called, is to use a lesser-known optical property to create a path for the beam.”
The second property, also known as non-Hermiticity in the field of photonics, refers to the flow of energy or, more specifically, the amplifying and attenuation of light. The associated effects can seem unpleasant, especially the fading of light beams due to absorption. This would be highly detrimental to the task of improving signal transmission. Non-Hermitian effects are a crucial aspect of modern optics. A whole field of research focuses on the intricate interplay between losses and amplifiers for advanced functionalities.
Andrea Steinfurth (a doctoral student) is the first author of this paper. It is possible to modify the microscopically amplified or dime-specific light beams to prevent degradation. It is possible to completely suppress the light scattering properties of the nebula to stay in the image. Steinfurth says they are currently working on modifying material to get the best transmission of a particular light signal. “To achieve this, the energy flow must also be controlled precisely so that it can work with the signal and material like pieces in a puzzle.”
The Rostock researchers overcame this challenge in close cooperation with their Vienna University of Technology partners. They reproduce and observe the microscopic interactions between light signals and their newly developed active material in networks of kilometres-long optical fibres.
Induced transparency is only one of many fascinating outcomes that can be drawn from these discoveries. It is essential to prevent scattering if an object is to disappear. Light waves must be able to emerge completely unaffected behind an object if it is to disappear. However, even in a vacuum of space, diffraction ensures that every signal will change its form. “Our research has provided the formula for structuring material so that light beams pass as though neither the material nor the region it occupies exist. Dr Matthias Heinrich, the co-author, says that not even the Romulans’ fictitious cloaking devices can achieve this feat.
These findings represent a breakthrough in fundamental research in non-Hermitian lightening and new methods for active fine-tuning sensitive optical systems such as medical sensors. There are also potential uses for optical encryption and secure data transmission.
