University of Adelaide researchers have developed the world's most sensitive thermometer, with three times more sensitivity than the current thermometers.
According to the study authors, the newly developed thermometer is capable of measuring temperature with a precision of 30 billionths of a degree.
"We've been able to measure temperature differences to 30 billionths of a degree in one second," project leader Professor Andre Luiten said in a press statement. "To emphasize how precise this is, when we examine the temperature of an object we find that it is always fluctuating. We all knew that if you looked closely enough you find that all the atoms in any material are always jiggling about, but we actually see this unceasing fluctuation with our thermometer, showing that the microscopic world is always in motion."
The thermometer uses light to measure temperature. It injects red and green light into a highly polished crystalline disk. The two colors travel at slightly different speeds in the crystal, depending on the temperature of the crystal. When the crystal is heated, the red light slows down by a tiny amount with respect to the green light.
"By forcing the light to circulate thousands of times around the edge of this disk in the same way that sound concentrates and reinforces itself in a curve in a phenomena known as a "whispering gallery" - as seen in St Paul's Cathedral in London or the Whispering Wall at Barossa Reservoir - then we can measure this minuscule difference in speed with great precision," Luiten said.
The technique used in the new development can also be used to redesign other ultra-sensitive measurement tools that are used to measure pressure, humidity, force or searching for a particular chemical.
The study was funded by the Australian Research Council and the South Australian Government's Premier Science and Research Fund. Findings were published online in the journal Physical Review Letters.
