June 2021: Book on Metasurfaces

Karim Achouri and Christophe Caloz publish the first textbook on metasurfaces. The book deals with all the aspect of metasurfaces across the electromagnetic spectrum from microwaves to optical frequencies.

The book is organized in the following chapters:

1. Introduction

2. Electromagnetic Properties of Materials

3. Metasurface Modeling

4. Susceptibility Synthesis

5. Scattered-Field Analysis

6 Fabrication

7. Applications


April 2021: STEAM Concept and Cloak

Einstein discovered in his development of the general theory of relativity, which he published in 1915, that the fabric of spacetime was curved by gravity. He concluded that such curving should deflect light around heavy cosmic objects, such as stars, which was experimentally verified by Eddington in 1919.

We recently discovered that such deflection of light could be produced without resorting to mass in terrestrial devices by leveraging perturbation modulation in Space-Time Engineered Accelerated Metamaterials (STEAMs). STEAMs can produce space-time curving effect as black holes, white holes and other gravitational systems, either static or dynamic (i.e., radiating gravitational waves). We reported a related novel cloak that is purely isotropic and that exhibits an unlimited bandwidth along with a polarization-independent response.

March 2021: Generalized Brewster Effect

The phenomenon of refraction without reflection at the interface between two media was first observed by Malus in 1808, next shown by Brewster in 1815 to occur at the inverse tangent of the ratio of the refractive indices of the two media, and finally explained by Fresnel in 1821 in his derivation, based on a mechanical model, of the eponymic reflection and transmission coefficients.

Until now, the Brewster angle was fixed by the indices of the two media and restricted to the TM polarization. In the paper Opt. Express, 7(29): 11361-70, 2021, (editor's pick), we generalize the Brewster effect to arbitrary angle and polarization by placing a properly designed bianisotropic metasurface at the interface.

This work represents a fundamental advance in optical science and technology, where it is expected to both improve the performance of conventional components and enable the development of novel devices.

June 2020: URSI GASS 2020 Young Scientist Award

Xiaoyi Wang is awarded the 2020 URSI (Union de Radio Science Internationale) GASS (General Assembly and Scientific Symposium) Young Scientist Award for his paper "Advances in Spacetime-Modulated Metasurfaces", whose abstract reads:

"Breaking the fundamental limitations of conventional time-invariant systems, spacetime-modulated metasurfaces have a transformative potential for modern electromagnetic technology. This paper reviews some of our recent research in this area, which includes the applications of spread spectrum camouflaging, Direction-of-Arrival (DoA) estimation, wireless multiplexing and tunable refraction. Moreover, it discusses the challenges related to this emerging technology."

February 2020: "Electromagnetic Perspectives"

Christophe Caloz launches in the IEEE Antennas and Propagation Magazine the new column "Electromagnetic Perspectives", and inaugurates it with a paper entitled "Electromagnetic Chirality, Part I: the Microscopic Perspective", which will be followed by "Electromagnetic Chirality, Part II: the Macroscopic Perspective" in the next issue of the journal.

"Electromagnetic Perspectives", highlighted in the editorial of the first 2020 issue of the magazine, intends to disseminate knowledge about electromagnetics and electrodynamics via paths that deviate from common routes and hence demystify concepts reputed of difficult access, by emphasizing historical contextualization, maximal simplification, pedagogical creativity and first-principle methodology.

The two-part paper "Electromagnetic Chirality", co-authored by Ari Sihvola, presents a bottom-up description of electromagnetic chirality, discovered 200 years ago by Arago and Biot and recently revived with metamaterials, from the microscopic level, characterized by particle polarizabilities, to the macroscopic level, characterized by medium susceptibilities.

January 2020: New Era of Magnetless Nonreciprocity

Our group introduced the concept of magnetless nonreciprocal metamaterials ten years ago [T. Kodera, D. L. Sounas, and C. Caloz, Appl. Phys. Lett., 2011]. Since then, this research topic has exploded in both the engineering and physics communities, with hundreds of related papers being published every month, including our critical perspective in [C. Caloz et. al, Phys. Rev. Appl., 2018].

The very recent conjunction of magnetless nonreciprocity and metasurface technologies has opened up a new research era where magnetless nonreciprocity is being combined with temporal and spatial wave spectra transformations.

October 2019: OSA Fellowship

Christophe Caloz was elected Fellow of the Optical Society of America (OSA), as part of the OSA Fellow Class 2020, with citation "for pioneering contributions to electromagnetic metamaterials and sustained leadership in bridging the gap between microwave and photonics technologies".

"The number of Fellows is limited by the Society's bylaws to be no more than 10% of the total OSA Membership and the number elected each year is limited to approximately 0.5% of the previous year's membership total. Currently, only about 50% of the nominees are elected annually."

See interview here.

September 2019: 1st Prize at Metamaterials' 2019

Zoé-Lise Deck-Léger wins the First Prize at the Student Paper Competition of Metamaterials' 2019, the 13th International Congress on Artificial Materials for Novel Wave Phenomena, in Rome, for a paper entitled "Comprehensive Description of Spacetime Crystal Bandgaps​ ".

An extension of this work has been recently published as a research article in Advanced Photonics under the title "Uniform-Velocity Spacetime Crystals". This article (26 pages) is expected to become a reference in the emerging field of spacetime metamaterials.

“Never, never, never give up.”

Winston Churchill