For all of human history, light has been instrumental to the development of new technology.

It's not just about having light to see, for example, to find sources of food. It's that those sources of food wouldn't exist without the presence of sunlight and photosynthesis.

How would humanity have invented the concept of time, if not by the light of the sun, moon, and stars? How would we have navigated and explored new places?

Even the Industrial Revolution was powered by coal, which is compressed biomatter originating from plants that grew a long time ago because of, you guessed it, the presence of light.

Now we have renewables, like solar panels, to power our modern electrical lives. But what if I was to tell you that light has even more in store for us?

You see, it could be the thing that powers our next technology revolution too, the quantum

revolution. And that is one very big idea for something I suspect we take for granted every day.

Light is powerful, versatile, and fascinating.

But what actually is it?

Your teacher at school probably told you that light is a wave. And since different wavelengths, or colours, of light travel through a prism at different speeds, you get a rainbow out the other side.

In the early 1900s, physicists such as Einstein discovered that light is made up of little balls of energy called photons. This means that every single thing you see around you is a result of these little photons hitting your eye.

Think about a fantastic romantic sunset. Most people like to think about the beautiful colours, the pinks, oranges, fading to blue. I like to think about not just what I'm seeing, but how I'm seeing it. Because what's more romantic than being bombarded with an army of tiny photons while you share a moment with someone you love?

Whether light is a wave or a particle depends on how you look at it. But regardless of how you look at it, we are using it for some amazing applications every day.

Lasers have revolutionised entire industries, from medicine to manufacturing, entertainment, and beyond. Telescopes pointed at outer space help us answer questions like, "What are the stars made of?"

And just as telescopes have opened a window to outer space, so microscopes have opened a window to the world of the cell and the microorganism, all using, you guessed it, light.

But I want to take you even further down to the nanoscale, 1,000 times as small as a cell. To help you picture how small this is, think about a blueberry. Now a blueberry is halfway in size between the world and an atom.

As the blueberry is to the world, so the atom is to the blueberry. And when things get small, they get weird.

Photons, like many atoms or subatomic particles, have different properties which lend themselves to being able to store information. For photons, this includes the wavelength or colour of light, its polarisation, the way it spins, and even the time of its arrival.

What's amazing is you can use any of these properties like the pages of a notebook on which to read and write information. Photons are also good at traveling.

If you can see me right now on the screen of your device, then you are experiencing the fact that photons can travel in free space. The problem is, if you want to send quantum information written on a photon, you need to be able to create and detect one single photon. That's one single energy ball of light.

In the lab at UNSW, we are working on both the creation and detection of these single photons. We produce our photons using silicon, the same stuff your computer is made of, and adding into it a fancy element called erbium. We use a laser to deliver a short burst of energy to the erbium atom, and in return, we get nice, precisely controlled photons.

For our experiments to work, we have to cool them down to an extremely cold temperature, close to absolute zero, which is minus 273 degrees Celsius. Think about how cold outer space is, far away from any kind of heat source like the sun, and then go about 100 times colder than that.

We also make detectors in-house that we can use to detect these single photons. Our detectors are based on a tiny little nanowire, which alerts us via an electrical signal every time we detect a photon. What we're building is a system that allows us to achieve full control over our photons, which will then unlock their potential for use in a variety of applications.

One of these applications is reliably transmitting information from A to B by writing it on a photon. I picture photons like little golden snitches from Harry Potter, flying around carrying information as they go. And just like a golden snitch or a locked diary, photons can carry little secrets, which can only be unlocked with the proper key.

But in this case, if you try to unlock them with the wrong key, the information will disappear. This offers a new paradigm of information security, because it means if the information falls into the hands of the wrong person and they try to unlock it, they can't because it's gone.

If this wasn't cool enough, you can even build a quantum computer out of light. These are futuristic, powerful computers that are likely to be able to solve challenges that stump our current computers. All you need is some kind of particle, like for example a photon, that you can read and write information on and a way to make them talk to each other.

We call these basic building blocks qubits, since they are the quantum version of the bits that make up our current, classical computers. Photons make good candidates for qubits, since not only can they store information, they can also travel, for example between different nodes of a computer.

What you need to do to be able to achieve this is to reliably create and detect single photons, which is the exact challenge we are working to solve in the lab. So I hope you can see the quantum world in a new light. It's exciting to dream about the quantum future and all that might be possible with the advent of quantum technologies, such as quantum computers.

It's a big deal with far-reaching implications. But underneath all the tech, I see a common foundation upon which we have built so much of our lives already. To me, the quantum revolution is the next step in a long history of technologies that relies upon the simplest, yet simultaneously the most intricately complex and beautiful thing I can think of, which is the power of the humble tiny photon. And that is one very big idea.