A group of researchers from University at Buffalo, California Institute of Technology and City University of New York has demonstrated a way to control light with light using one third – in some cases, even less – of the energy typically required. The advancement, coupled with other developments, could lead to more powerful, energy-efficient chips and other optics-based technologies.
"Typically, symmetry connotes harmony and beauty. But not in this case. We've developed technology – an asymmetric metawaveguide – that enables a weak control laser beam to manipulate a much more intense laser signal," says Liang Feng, assistant professor at Buffalo University.
Light-light switching typically requires strong nonlinearity where intense laser fields route and direct data flows of weak power, leading to a high power consumption that limits its practical use.
In this study, the experimental demonstration of a metawaveguide – a tiny rectangular box made of silicon – operates in the opposite way in a linear regime, where an intense laser field is interferometrically manipulated on demand by a weak control beam with a modulation extinction ratio up to 60dB. This asymmetric control is said to result from operating near an exceptional point of the scattering matrix, which gives rise to intrinsic asymmetric reflections of the metawaveguide through interplay between index and absorption.
Pic: The image shows a weak control beam (narrow red line, far right) and a more intense laser signal (larger red line, far left) within an asymmetrical metawaveguide. Credit: University at Buffalo.
Author
Peggy Lee
Source: www.newelectronics.co.uk