Picture of the world's smallest diamond ring, measuring 300 nanometers (billionths of a meter) thick and 5 microns (millionths of a meter) across. The ring was made by carving out a circular structure in an artifically made diamond.

Scientists have created the world's smallest diamond ring.

At only 5 microns (or millionths of a meter) in diameter and 300 nanometers (or billionths of a meter) in thickness, this rock won't get any 'oohs' or 'ahhs' from admiring friends.

But it can help scientists who are developing quantum information processing: The ring is a component in a device for producing and detecting single photons, or particles of light.

Set in different states, photons can carry information. In ordinary digital computers, information is stored in bits, which can have a value of either "1" or "0" (just as a light switch can only be "on" or "off"). The order of 1's and 0's indicates a certain piece of information.

But these photons, called qubits, can hold a value of 1 and 0 at the same time, which could expand the possibilities for information storage.

The new development, announced at the March meeting of the American Physical Society in New Orleans, was made by scientists at the University of Melbourne in Australia.