Synthetic phonons enable nonreciprocal coupling to arbitrary resonator networks

See allHide authors and affiliations

Science Advances  08 Jun 2018:
Vol. 4, no. 6, eaat0232
DOI: 10.1126/sciadv.aat0232


Inducing nonreciprocal wave propagation is a fundamental challenge across a wide range of physical systems in electromagnetics, optics, and acoustics. Recent efforts to create nonreciprocal devices have departed from established magneto-optic methods and instead exploited momentum-based techniques such as coherent spatiotemporal modulation of resonators and waveguides. However, to date, the nonreciprocal frequency responses that these devices can achieve have been limited, mainly to either broadband or Lorentzian-shaped transfer functions. We show that nonreciprocal coupling between waveguides and resonator networks enables the creation of devices with customizable nonreciprocal frequency responses. We create nonreciprocal coupling through the action of synthetic phonons, which emulate propagating phonons and can scatter light between guided and resonant modes that differ in both frequency and momentum. We implement nonreciprocal coupling in microstrip circuits and experimentally demonstrate both elementary nonreciprocal functions such as isolation and gyration, as well as reconfigurable, higher-order nonreciprocal filters. Our results suggest nonreciprocal coupling as a platform for a broad class of customizable nonreciprocal systems, adaptable to all wave phenomena.

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.

View Full Text

Stay Connected to Science Advances