A groundbreaking study from physicists at Leiden University has successfully replicated Thomas Young’s famous double-slit experiment using sound waves for the first time. Published on November 13, 2025, in the journal Optics Letters, this research offers fresh insights into the behavior of sound at the smallest scales, with potential applications in 5G technology and the evolving domain of quantum acoustics.
The original double-slit experiment, conducted in 1801, demonstrated that light exhibits both wave-like and particle-like properties. In this latest study, Ph.D. student Thomas Steenbergen and his colleague Löffler sought to explore whether sound waves could show similar behaviors. Their work builds upon a project initiated by Krystian Czerniak, an undergraduate physics student.
To conduct the experiment, the researchers utilized gigahertz sound waves—oscillating at a billion times per second, far beyond the audible range for humans. They directed these sound waves at a small sample of gallium arsenide, a semiconductor commonly used in electronics. With precision, Matthijs Rog from Kaveh Lahabi’s team carved two microscopic slits into the material using an ion beam.
Steenbergen described the measurement process, noting, “We then measure the sound with an extremely precise optical scanner. This device can measure sound literally everywhere, including in and in front of the slits. We can measure the height of the sound waves with picometer precision—that’s one millionth of a micrometer.”
The experiment produced an interference pattern similar to that seen with light, revealing areas where sound waves reinforced or canceled each other. Steenbergen pointed out a crucial distinction, stating, “But if you look closely, you also see that the pattern is not completely symmetrical. Sound waves don’t move the same way in all directions. The speed of the waves depends on the angle at which they pass through the material.”
Through the development of a mathematical model, the research team successfully explained and predicted these variations in sound behavior. This advancement opens new avenues for understanding sound in various applications, particularly in the telecommunications industry, where gigahertz sound waves are integral to 5G devices.
The implications of this research extend beyond telecommunications. It also provides valuable insights for emerging technologies in quantum acoustics, where sound waves operate on quantum scales, potentially facilitating new methods of information transfer.
This innovative approach illustrates how concepts from centuries-old experiments continue to inspire and inform modern scientific inquiry, leading to advancements that bridge the gap between theory and practical application. As researchers explore the interplay between sound and light, the field of physics continues to evolve, promising exciting developments in various technological arenas.
For further details, refer to the study by Thomas Steenbergen et al., titled “Young’s double-slit experiment with anisotropic GHz surface acoustic waves on gallium arsenide,” published in Optics Letters.
