University of Innsbruck researchers discovered how light can be measured non-destructively through a quantum sensor that could also permit the study of light's quantum properties.
Team leader and physicist Tracy Northup is conducting research on developing quantum internet at the said university. The research involves creating interfaces that allow quantum information to be transferred from matter to light and vice versa. This has a global potential as quantum computers all over the world could possibly communicate with each other through fiber-optic lines. Her team has shown a non-destructive method in measuring visible light. "The development follows the work of Serge Haroche, who characterized the quantum properties of microwave fields with the help of neutral atoms in the 1990s and was awarded the Nobel Prize in Physics in 2012," according to Phys.
Researchers Moonjoo Lee and Konstantin Friebe set up two hollow mirrors with an ionized calcium atom in-between that guided visible laser light. "The ion has only a weak influence on the light," explains Tracy Northup. "Quantum measurements of the ion allow us to make statistical predictions about the number of light particles in the chamber." The physicists were supported in their interpretation of the measurement results by the research group led by Helmut Ritsch, an Innsbruck quantum optician from the Department of Theoretical Physics. "One can speak in this context of a quantum sensor for light particles", sums up Northup, who has held an Ingeborg Hochmair professorship at the University of Innsbruck since 2017. One application of the new method would be to generate specially tailored light fields by feeding the measurement results back into the system via a feedback loop, thus establishing the desired states.
