First observation of de Broglie-Mackinnon wave packets achieved by exploiting the loophole in the 1980s theorem

Researchers at the University of Central Florida College of Optics and Photonics achieved the first observation of Broglie-Mackinnon wave packets by exploiting a loophole in a laser physics theorem from the 1980s.

He research work by CREOL and Professor Ayman Abouraddy of the Florida Photonics Center of Excellence and Research Assistant Layton Hall has been published in the journal physics of nature.

The observation of de Broglie-Mackinnon optical wave packets highlights the team’s research using a class of pulsed laser beams they call space-time wave packets.

In an interview with Dr. Abouraddy, he provides more insight into his team’s research and what it may hold for the future.

He achieved several ‘firsts’ during this phase of his research. Could you provide us with some history of the theoretical ideas that brought you here?

In the early days of the development of quantum mechanics nearly 100 years ago, Louis de Broglie made the crucial conceptual breakthrough of identifying waves with particles, sometimes called wave-particle duality. However, a crucial dilemma was not resolved. Particles are spatially stable: their size doesn’t change as they travel, however waves do change, spreading out in space and time. How can you build a model from the waves suggested by de Broglie that nevertheless corresponds precisely to a particle?

In the 1970s, L. Mackinnon proposed a solution by combining Einstein’s special theory of relativity with de Broglie waves to construct a stable “wave packet” that does not propagate and can therefore accompany a wave. traveling particle. This proposal went unnoticed because there was no methodology to produce such a wave packet. In recent years, my group has been working on a new class of pulses. laser rays we have called ‘space-time wave packets’, which travel rigidly in free space.

In our recent research, Layton extended this behavior to propagation in dispersive media, which normally stretch optical pulses, except for packets of spacetime waves that resist this stretch. He recognized that the propagation of space-time wave packets in a medium endowed with a special type of scattering (so-called ‘anomalous’ scattering) corresponds to Mackinnon’s proposal. In other words, the packets of space-time waves are the key to finally achieving de Broglie’s dream. By carrying out laser experiments in this regard, we observed for the first time what we have called Broglie-Mackinnon wave packets and verified their predicted properties.

What is unique about your results?

There are several unique aspects of this document. This is the first example of a pulse propagating invariably in a medium with anomalous dispersion. In fact, a well-known laser physics theorem from the 1980s purports to prove that such a feat is impossible. We found a loophole in that theorem that we exploited when designing our optical fields.

Also, all of the above pulsed fields that propagate unchanged are X-shaped. It has long been theorized that O-shaped propagation invariant wave packets should exist, but have never been observed. Our results reveal the first observed O-shaped propagation invariant wave packets.

The US Office of Naval Research is supporting their investigation. In what ways are their findings useful to them and to others?

We still don’t know exactly. However, these findings have practical consequences in terms of the spread of optical pulses in dispersive media without suffering the deleterious impact of dispersion.

These results may pave the way for optical proofs of solutions of the Klein-Gordon equation for massive particles, and may even lead to the synthesis of non-dispersive wave packets using matter waves. This would also allow new detection and microscope techniques.

Which are the next steps?

This work is part of a larger study of the propagation characteristics of wave packets in space-time. This includes the long-distance propagation of wave packets in space-time that we are testing at the UCF Townes Institute for Science and Technology Experimentation Facility (TISTEF) on the space coast of Florida. From a fundamental perspective, the optical spectrum that we have used in our experiments is in a closed path. This has never been achieved before, and opens the way to study topological structures of light on closed surfaces.