Record-breaking laser binding could provide a test of Einstein’s theory

Scientists at the International Radio Astronomical Research Center (ICRAR) and the University of Western Australia (UWA) set a world record for the most stable transmission of a laser signal through the atmosphere.

In a study published today in the journal Nature communications, Australian researchers have joined forces with researchers from the French National Center for Space Studies (CNES) and the French Time-Space Reference Systems (SYRTE) metrology laboratory at the Paris Observatory.

The team set the world record for the most stable laser transmission by combining Australian phase stabilization technology with advanced self-guided optical terminals. Together, these technologies have made it possible to send laser signals from one point to another without interference from the atmosphere.

Lead author Benjamin Dix-Matthews, a Ph.D. student at ICRAR and UWA, said the technique effectively removes atmospheric turbulence. “We can correct atmospheric turbulence in 3-D, that is, left-right, up-down and, critically, along the line of flight,” he said. “It is as if the moving atmosphere has been suppressed and does not exist. It allows us to send very stable laser signals through the atmosphere while maintaining the quality of the original signal.”

The result is the world’s most accurate method for comparing the flow of time between two separate locations using a laser system transmitted through the atmosphere.

Dr Sascha Schediwy, senior researcher at ICRAR-UWA, said the research has interesting applications. “If you have one of these optical ground terminals and another on a satellite in space, then you can start exploring fundamental physics,” he said. “Everything from testing Einstein’s general theory of relativity more precisely than ever before, to finding out whether fundamental physical constants change over time.”

The precise measurements of technology also have practical uses in earth sciences and geophysics. “For example, this technology could improve satellite studies of how the water table changes over time, or to search for underground ore deposits,” said Dr Schediwy.

There are other potential benefits for optical communications, an emerging field that uses light to carry information. Optical communications can safely transmit data between satellites and Earth at much higher data rates than current radio communications.

“Our technology could help us increase the data rate from satellites to the ground by orders of magnitude,” said Dr Schediwy. “The next generation of large data collection satellites would be able to transmit critical information to the ground faster.”

The phase stabilization technology behind the record link was originally developed to synchronize incoming signals for the Square Kilometer Array telescope. The multibillion-dollar telescope is slated to be built in Western Australia and South Africa from 2021.

Provided by the International Center for Research in Radio Astronomy