Quantum technologies move a step closer with demonstration of 'entanglement' filter

Washington, Jan 25 (ANI): A team of physicists and engineers has demonstrated an 'entanglement' filter, an optical device that filters two particles of light (or photons) based on the correlations between their polarization, which brings scientists a step closer to quantum technologies.

The device has been made by Jeremy O'Brien, Professor of Physics and Electrical Engineering at Bristol University, together with his collaborators in Japan.

It was made by combining two state-of-the-art developments in optical technologies with single photons: a special type of mirror that is sensitive to the polarisation of light; and an optical device that enables stability at the billionth's of a meter level.

This so called "entanglement filter" passes the pair of photons only if they inhabit the same quantum state, without the user ever knowing what that state is.

This device will have many important applications to quantum technologies, including computers, communication and advanced measurement.

According to Professor O'Brien, "This is a very exciting development in quantum information science. Because our entanglement filter acts on photonic qubits, it is promising for quantum technologies because photons are the logical choice for communication, metrology and lithography and are a leading approach to information processing."

"The filter can be used for the creation as well as the purification of entanglement, which will be important in realising quantum relays and repeaters for long-distance quantum communication," he added.

Filters are one of the most powerful tools available in science and technology, while entanglement is the defining characteristic of quantum information science.

An entanglement filter is of fundamental interest and will likely find wide application in quantum information science and technology.

The entanglement filter will be a key element in the control of multiphoton quantum states, with a wide range of applications in entanglement-based quantum communication and quantum information processing. (ANI)