Invisibility Cloaks
Sonia Shum '27
Since the Scientific Revolution in the 16th to 17th century, science-fiction has been a prevailing genre across all forms of literature, inspired by our technologically advancing world. Science fiction explores fantasies made real by possibilities such as the Quantum Realm, time travel, nanotechnology, etc., and their societal implications. In June 2024, researchers at Macquarie University developed a new software package, TMATSOLVER, that can accurately simulate how waves scatter when they meet complex configurations of particles, advancing potential metamaterial design (ScienceDaily, 2024). This breakthrough raises exciting questions: Can invisibility cloaks become a reality? How will our lives change as our world draws nearer to science fiction?
Metamaterials are artificial mediums constructed from conventional materials such as metals and plastics. They are bent into exact shapes, sizes, orientations, and arrangements in order to achieve special electromagnetic properties (META® Team, 2017). Metamaterials consist of a multitude of material pieces smaller than the wavelengths they intend to interact with, affecting the waves unnaturally. Hence, metamaterials can control sound, heat, and light waves, producing unusual effects such as electromagnetic cloaking and negative refraction indexes (META® Team, 2017).
Our visual abilities rely on collecting light reflected off an object’s surface. Special cells turn the light into electrical signals sent to our brains, which perceive the signals and present them as images. Our perception of light relies on the predetermined notion that light travels in a straight line (Hossenfelder, 2022). Natural materials, such as glass and water, can distort and change the path of light. The angle at which light refracts depends on the media’s refractive indexes—the ratio of the speed of light in a vacuum versus the medium. A negative refractive index, an unnatural property only achieved through metamaterials, would reflect the light, making it return in the direction it came from. Theoretically, the right combination of materials and metamaterials could bend light around an object, obscuring it from our vision, as we can only perceive objects interacting with light (Hossenfelder, 2022). Using this technology, metamaterials could potentially construct an invisibility cloak.
The TMATSOLVER software developed by researchers at Macquarie University uses a transition matrix (T-matrix)—a grid of numbers—to fully describe how complex configurations of
particles scatter waves (ScienceDaily, 2024). The software can accurately compute matrices for a wide range of particles, allowing researchers to test far more complicated geometries. Dr. Stuart Hawkins from Macquarie University’s Department of Mathematics and Statistics reports how the TMATSOLVER software allows for “rapid prototyping and validation of new metamaterial design,” extending the possibilities of controlling all kinds of waves (ScienceDaily, 2024).
A breakthrough in metamaterial design would transform the future of technology. Besides potentially developing invisibility cloaks, TMATSOLVER could create noise reduction barriers and protection against seismic activity by constructing metamaterial barriers that absorb or deflect sound and seismic waves more effectively than traditional materials. Metamaterial configurations designed to trap, convert, and recycle energy carried within the waves could also advance clean energy and wireless power (Khromova, 2019). Professor Lucy Marshall, Executive Dean, Faculty of Science and Engineering at Macquarie University says the TMATSOLVER software is a “prime example of how innovative computational methods can drive advancements in materials science and engineering” (ScienceDirect, 2024).
References
Hossenfelder, S. (2022, September 17). Meta-Materials: Invisibility Cloaks, Superlenses, And Earthquake Protection [Video]. YouTube.
https://www.youtube.com/watch?v=iNugreoNuo0&t=716s&ab_channel=SabineHossenfelder Invisibility cloaks? Wave scattering simulation unlocks potential for advanced metamaterials. (2024, September 12). ScienceDirect. Retrieved October 6, 2024, from
https://www.sciencedaily.com/releases/2024/09/240912135948.htm
Khromova, I. (2019, May 9). How metamaterials could one day bring the impossible to life. techradar. Retrieved October 6, 2024, from
https://www.techradar.com/news/how-metamaterials-could-one-day-bring-the-impossible-to-l ife
META® Team. (2017, November 2). What Are Metamaterials? META Go Beyond. Retrieved October 6, 2024, from https://blog.metamaterial.com/what-are-metamaterials