Geoffroy Lerosey
Institut Langevin, CNRS – ESPCI ParisTech
1 rue Jussieu, 75005 Paris, France
Postdoctoral fellowship available for 1 or 2 years
“Wave propagation at the deep subwavelength scale in locally
resonant metamaterials »
In the last pas years, we have analyzed in a new way the propagation of electromagnetic and
acoustic waves in locally resonant media, that is, metamaterial made out of resonant unit cells.
This has for example permitted us to develop new methods to image and focus from the far
field beyond the diffraction limit in acoustics (Fig a), microwave or optics [1-3]. Similarly, we
have adopted a microscopic approach to those media and proved that under some
circumstances, they can be used as photonic or phononic crystals to guide, confine, and control
waves (Fig b), with the very difference that now this can be done at the deep subwavelength
scale [4-5].
Figure: a) deep subwavelength focal spot obtained using far field time reversal on top of an array of soda cans, and b)
waveguiding microwaves at the deep subwavelength scale in an array of locally modified resonant electric wires
We have just received a positive response for a grant proposal aimed at following these efforts
in the understanding and utilization of locally resonant metamaterials, which includes a two
years postdoc fellowship. The idea of the project is to develop fully the equivalence between
metamaterials and crystals, to underline the limitations of the equivalence, and to propose new
concepts based on this idea. In particular, we will seek ways to engineer near field coupling in
metamaterials and to zero it, we will study metamaterials made out of different kinds of
resonant unit cells (like diatomic crystals) as well as media made out of different spatial scales.
We will also study the effect of introducing disorder in this kind of media by using unit cells
which present a disordered distribution of resonance frequencies. We will finally develop
applications based on our ideas, for instance we would like to develop deep subwavelength
waveguides which present very high group index for radar or telecommunication applications
in the microwave domain, or deep subwavelength cavities for enhanced light/matter
interactions throughout the spectrum. The workload includes simulations in acoustics
microwave or other electromagnetic areas (Comsol, CST), experimental work in acoustics and
microwave, as well as theoretical works. We have already two permanents working on the
projects as well as two PhD students.
The candidate should have a PhD in solid state physics, electrical engineering or acoustics, with
a solid expertise in metamaterials, photonic/phononic crystals or related topics such as spoof
plasmons or so. The candidate can be more experimental, simulation or theory oriented, but a
transverse profile who can work on every aspect is preferred. The background of the candidate
can be either acoustics or EM, since we will work in both areas, and since they are very similar.
We are looking for someone autonomous and creative, we will appreciate to interact with other
researchers. The candidate should have a good record of publication, although motivation and
passion for wave physics will be the main criteria of selection.
1 - Lemoult, F., Lerosey, G., de Rosny, J. and Fink, M. “Resonant Metalenses for Breaking the Diffraction Barrier”. Physical
Review Letters 104, 203901, (2010).
2 - Lemoult, F., Fink, M. and Lerosey, G. “Acoustic resonators for far field control of sound on a subwavelength scale”. Physical
Review Letters 107, 064301 (2011).
3 - Lemoult, F., Fink, M. and Lerosey, G. “A polychromatic approach to far field superlensing at visible wavelengths”. Nature
Communications 3, 889 (2012).
4 - Lemoult, F., Kaïna, N., Fink, M. and Lerosey, G. “Wave propagation control at the deep subwavelength scale in
metamaterials”. Nature Physics 9, 55–60 (2013).
5 - Kaïna, N., Lemoult, F., Fink, M. and Lerosey, G. “Ultra-low mode volumes defect cavities in ordered and disordered
metamaterials”. Applied Physics Letters 102, 144104 (2013).
How to apply:
Send CV and letter to geoffroy.lerosey@espci.fr
1 or 2 years possible, preferably 1 year contract renewed.
The postdoc can start any time from October 1st to January 1st. (Dates could be more flexible
for excellent candidates)
Salary between 2150e/months up to 2800e/months depending on experience.