Exact shape of a single photon revealed for the first time

11-29-2024

ByEric Ralls
Earth.com staff writer

Light is something we interact with every day, but have you ever wondered what the shape of a single particle of light — the photon — actually looks like?
For the first time, researchers have defined the precise shape of a single photon, a huge leap forward in quantum physics and material science.

Dr. Benjamin Yuen from the University of Birmingham led the groundbreaking research that delves deep into the quantum level of light and matter interaction.
His team’s findings, published in Physical Review Letters, provide a visual representation of a photon while enhancing our understanding of how photons are emitted and shaped by their environment.

Understanding photons — the basics
A photon is the fundamental unit of light and all electromagnetic radiation. Unlike particles that have mass, photons are massless and always move at the speed of light.
They exhibit both particle-like and wave-like properties, a concept known as wave-particle duality.
Photons carry energy and momentum, determined by their frequency or wavelength. Simply put, the higher the frequency, the more energy a photon possesses.
This unique dual nature allows photons to interact with matter in special ways, such as being absorbed or emitted by atoms.
These interactions are essential for processes like vision, photosynthesis, and the technology behind our electronic devices.
Photon shape and the “far field”
The interaction between photons and their environment leads to endless possibilities for how light exists and travels.
This limitless potential makes modeling these interactions exceptionally challenging — a puzzle that quantum physicists have been trying to solve for decades.

“Our calculations enabled us to convert a seemingly unsolvable problem into something that can be computed,” Dr. Yuen explained.

“And, almost as a byproduct of the model, we were able to produce this image of a photon, something that hasn’t been seen before in physics.”By grouping the infinite possibilities of photon interactions into distinct sets, the team produced a model that describes not only how photons interact with the atoms or molecules that emit them, but also how the energy from that interaction travels into the distant surroundings, known as the “far field.”

Why do we care about photon shape?
We depend on photons more than we might realize. Our eyes detect photons, allowing us to see the world around us.
In technology, photons are crucial for solar panels that convert light into electricity and fiber optic cables that provide high-speed internet and communications.
Photons also play a significant role in scientific research. They are central to quantum electrodynamics (QED), the theory that describes how light and matter interact.
Photons act as force carriers for the electromagnetic force, one of the four fundamental forces in the universe.
They facilitate interactions between charged particles like electrons and protons, governing a wide range of physical phenomena.

Advancing quantum physics
“The geometry and optical properties of the environment have profound consequences for how photons are emitted, including defining the photons’ shape, color, and even how likely it is to exist,” explained co-author Professor Angela Demetriadou.

• Understanding the precise shape and behavior of photons could revolutionize the way we design nanophotonic technologies.

This could lead to advancements in secure communication methods, improved detection of pathogens, and even control over chemical reactions at a molecular level.
“This work helps us to increase our understanding of the energy exchange between light and matter, and to better understand how light radiates into its nearby and distant surroundings,” Dr. Yuen added.
“Lots of this information had previously been thought of as just ‘noise’ — but there’s so much information within it that we can now make sense of and make use of.”

What happens next?
By comprehending how photons interact with their environment, scientists can engineer light-matter interactions for future applications.
Imagine better sensors that can detect diseases at an early stage, more efficient solar cells that provide cleaner energy, or advancements in quantum computing that could solve complex problems in seconds.

“By understanding this, we set the foundations to be able to engineer light-matter interactions for future applications,” says Dr. Yuen.
The possibilities are vast and could significantly impact various fields, from healthcare to technology and environmental science.

Photon shape and future technology

To sum it all up, this fascinating research represents a significant step forward in quantum physics.
By defining the precise shape of a single photon, the team has provided a tool that could help scientists and engineers design new technologies that harness the unique properties of light.
The findings not only answer long-standing questions about the fundamental nature of photons but also open up new questions and research paths.
As we continue to explore the quantum world, understanding the building blocks of light will be crucial in pushing the boundaries of what’s possible.
The visualization of a photon is a testament to human curiosity and our desire to understand the universe at its most fundamental level.
With this new knowledge, we’re not just looking at light differently — we’re poised to use it in ways we never thought possible.

The full study was published in the journal Physical Review Letters.