Towards precision

In what seems like the ultimate contradiction in terms, even highly refined light suffers from 'noise' pollution. This limits its accuracy as a measuring device in ultrafine research. Now researchers at the Australian National University (ANU), Canberra, have succeeded in producing 'clean and squeezed' light. The result bears significance for work on ultraprecise measurements in spectroscopy and for detecting very faint signals such as electromagnetic emissions from silicon chips.

The light can also be used for detecting faint signals of all gravitational waves from deep space, set off by stellar explosions. After four years of research, the ANU achieved success by using a bistable cavity-atom system. By passing a laser beam through barium atoms in a cavity, it reduced quantum noise by a factor of two below its original limits.