Reciprocity is a fundamental principle in optics, requiring that the response of a transmission
channel is symmetric when source and observation points are interchanged. It is of major …

We aim at providing a global perspective on electromagnetic nonreciprocity and clarifying
confusions that arose in recent developments of the field. We provide a general definition of …

Integrated photonics enables signal synthesis, modulation and conversion using photonic
integrated circuits (PICs). Many materials have been developed, among which silicon nitride …

Non-reciprocal components, which are essential to many modern communication systems,
are almost exclusively based on magneto-optical materials, severely limiting their …

Nonreciprocal components, such as isolators and circulators, provide highly desirable
functionalities for optical circuitry. This motivates the active investigation of mechanisms that …

Metasurfaces characterized by a transverse gradient of local impedance have recently
opened exciting directions for light manipulation at the subwavelength scale. Here we add a …

Time-reversal symmetries impose stringent constraints on emission and absorption.
Antennas, from radiofrequencies to optics, are bound to transmit and receive signals equally …

Optical isolators today are exclusively built on magneto-optic principles but are not readily
implemented within photonic integrated circuits. So far, no magnetless alternative …

Isolators are devices that transmit waves only in one direction, and are widely used to
protect sensitive equipment from reflections and interference. These devices inherently …

Magnetic-free optical non-reciprocal components, such as isolators and circulators, are
highly desirable for on-chip optical signal processing, and quantum networks,. However …