Towards practical quantum metrology with photon counting
25 August 2016
Scientists are harnessing quantum physical effects to achieve sensors with unprecedented sensitivity. Researchers from the Centre for Quantum Photonics have sought a new approach to quantum measurements and have had their results published in Nature.
Traditionally classical optical experiments are limited in sensitivity due to the background noise present in all measurements—intensity fluctuations dictated by quantum mechanics. More sensitive measurements can be achieved by using quantum effects, but such schemes require tolerance of the ever-present optical losses that occur during quantum measurements.
Dr Jonathan Matthews has worked with colleagues from the Centre for Quantum Photonics to find a new method of using quantum effects in sensing, combining state-of-the-art quantum photonics to enable a quantum advantage to be achieved without using post-selection. They have found that by counting the light particles generated during spontaneous parametric downconversion—a process in which photons in a laser beam are split into a pair of photons—experimental results beyond the classical noise limit could be achieved.
The enhanced sensitivity enabled by quantum effects could be important for experiments detecting gravitational waves or in applications such as biological sensing.
The full article can be read online in Nature.