Set Photons to Switch

Jonathan Strickland

Sergey Nivens/iStock/Thinkstock

What if you could create a photonic switch that's just one atom in size? Well, you'd be late to the game, because researchers at Harvard got there ahead of you. Their work could hold the key to creating a more secure Internet for everyone.

Here's how it works -- engineer a system in which a single atom can act as a switch that either permits photons to pass or blocks them. A photon, you'll recall, is a particle of light. Not only can the atom-switch act as a bouncer for light particles, a single photon can change the atom's state from on to off or off to on.

Such a switch might become an integral component of a quantum-based Internet infrastructure, which is where Internet security comes in. Quantum mechanics is a complicated subject that tends to make my head feel fuzzy if I dig in too deeply. But basically, one of the principles you have to take into consideration when dealing with the quantum world is that the act of observing affects that which is observed.

With quantum cryptography, this principle comes in handy. If you were to encrypt a message using quantum cryptography, not only would it be fiendishly difficult to decrypt using classical means but it would also be impossible for you to do so without leaving signs of your attempt. By interfering with the system, you change it, which leaves behind evidence. That's bad news for your typical spy, scalawag or snoop.

On the surface, it all sounds so simple. Take some atoms, do something to them, hit them with photons and you've got yourself a secure Internet. But in reality, the process is quite complicated and involves lowering the temperature of atoms to near absolute zero, bombarding them with lasers and other electromagnetic radiation and keeping them suspended inside a vacuum. Make sure you check out the linked article to read more about the fascinating discovery and potential applications!