## Symposium France-Recife Collaboration in Physics

September - 2nd and 3td
ONLINE
STARTING AT 9:45 (GMT-3)

## Speakers

### Martial DUCLOY

Université Sorbonne Paris-Nord/CNRS-France

### Andre MYSYROWICZ

LOA, ENSTA, institut polytechnique de Paris-France

### Albert FERT

Université Paris-Saclay, UMPhy. CNRS-Thales, Palaiseau, France

### Georges BOUDEBS

Université Angers, LPHIA, SFR MATRIX, F-49000 Angers, France

### Daniel BLOCH

Université Sorbonne Paris-Nord/CNRS-France

### Laurence PRUVOST

Université Paris-Saclay/CNRS-France

### Robin KAISER

Université de la Côte d’Azur/CNRS-France

## Schedule

SYMPOSIUM FRANCE-RECIFE COLLABORATION IN PHYSICS

9:30 - 10:00
(GMT-3)

### Opening

Welcome

10:00 - 10:45
(GMT-3)

#### Martial DUCLOY

Université Sorbonne Paris-Nord/CNRS-France

### 40 years of Nordeste-Paris Nord scientific collaboration: when two "Norths" meet...

10:45 - 11:20
(GMT-3)

#### Andre MYSYROWICZ

LOA, ENSTA, institut polytechnique de Paris-France

### Femtosecond laser filamentation and applications

Femtosecond filamentation is a spectacular phenomenon whereby a short laser pulse propagates nonlinearly through a transparent medium allowing high peak light intensities to be transferred over distances far exceeding the beam Rayleigh length, as if diffraction were suppressed. In this talk, after a brief description of some key features of filamentation, I put the accent upon some potential applications.

11:20 - 11:55
(GMT-3)

### France - Recife collaboration... in Uruguay

I will present a quick overview of the research topics addressed in our laboratory that have been strongly motivated and propelled by our collaborations with our colleagues in Recife and France.

11:55 - 12:15
(GMT-3)

Interval

### Interval

20 minutes

12:15 - 12:50
(GMT-3)

#### Martine CHEVROLLIER

Universidade Federal Rural de Pernambuco - BRAZIL

### Experimental atomic physics and nonlinear dynamics: A french experience in Brazil

In this talk, we will comment on a scientific trajectory that began in France and took place in Brazil for almost 30 years, while we maintained good contacts with French collaborators. We will briefly mention our lines of research in atom-surface interactions, light propagation in resonant atomic media and more recently in nonlinear dynamics. Many Brazilian students have been involved in these projects, both in our laboratories and in those of our collaborators in France.

12:50 - 13:25
(GMT-3)

#### José R RIOS LEITE

Universidade Federal de Pernambuco - BRAZIL

### On some DF-UFPE research collaborations with French Laboratories

Over four decades of joint collaboration with French institutions helped shape research lines and graduate students work in our laboratory at UFPE-Recife. We shall summarize Laser Molecular and Atomic Spectroscopy, Nonlinear Optics and Laser Chaotic Dynamics topics that were addressed in exchange visits with the Laboratoire de Physique des Lasers - University Paris 13, Laboratoire Kastler-Brossel- Jussieu - Université ParisVI and Institut Nonlineaire de Nice.

09:45 - 10:00
(GMT-3)

### Welcome

10:00 - 10:45
(GMT-3)

#### Albert FERT

Université Paris-Saclay, UMPhy. CNRS-Thales, Palaiseau, France

### From topology to devices: examples in spintronics

I want to discuss two types of problem:
1) Conversion between spin and charge currents by topological 2DEGs at surfaces or interfaces: After an introduction to the physical mechanisms of these conversions, I want to focus on recent developments on the way to logic or memory devices based on the exploitation of surface/interface states of SrTi03 [1] and Dirac semimetal alpha-Sn [2].
2) The second part of the talk will be on the perspective with bidimensional (2D) van der Waals materials and I will discuss two topics: a) Chiral interactions and skyrmions in 2D van der Waals magnets [3-4] b) Prospects with multiferroic 2D materials.

Figure: current-induced motion of skyrmions in the 2D magnet Fe3GeTe2 [4].

[1] Lesne et al, Nature Materials, 15, 1261, 2016. Noël et al, Nature 380, 483, 2020
[2] Rojas-Sanchez et al, PRL 116, 096602, 2016. Ding et al, Adv. Mater. 2021, DOI: 10.1002/adma.202005909
[3] Liang et al, PR B 101, 1844, 2019.
[4] Park et al PR B 103, 104410, 2021.

10:45 - 11:20
(GMT-3)

#### Georges BOUDEBS

Université Angers, LPHIA, SFR MATRIX, F-49000 Angers, France

### Recife/Angers: 20 years of collaboration in the field of optical systems and applications to third order nonlinear characterization techniques.

Within the framework of our collaboration between our two labs, this presentation will review the results obtained by optical systems for nonlinear characterization of materials mainly using the Z-scan technique in a 4f setup. Starting from theoretical considerations to which will be associated numerical simulations, I will present the experimental setup that has been used, its variants (D4sigma, Dark field Z-scan...), the advantages and inconveniences of the different techniques with some results on materials.

11:20 - 11:55
(GMT-3)

#### Daniel BLOCH

Université Sorbonne Paris-Nord/CNRS-France

### How the 1982 sabbatical year of J R Rios Leite at Berkeley was very fruitful for us

Spectroscopy of free atoms, and resonant nonlinear optics with four-wave mixing, had been central to our activity in LPL Villetaneuse, and has shifted for decades to the probing of surface interaction with atoms, eventually involving the thermal emission of hot surfaces. This shift was notably induced by early discussions with JR Rios Leite on evanescent waves, a topic he has become familiar with his stay at YR Shen lab in Berkeley, when early "nanophotonics" was pioneered with surface plasmons.
The topic of resonant Nonlinear Optics, still active at Recife and partly imported from Villetaneuse, has been seminal to our own interest in light beams twisted with Orbital Angular Momentum. Molecular spectroscopy, recently achieved in Villetaneuse close to surfaces, is also a topic which was partly "imported" from DF-UFPe, where the early experiments of wave-mixing had been initiated with CO2 lasers. The tropical collaboration celebrated by the meeting was enriched by very strong and friendly human links;, and, scientifically, it has always provided the freedom of discussing a variety of topics, including those on which we finally do not contribute.

11:55 - 12:15
(GMT-3)

<Interval

### Interval

20 minutes

12:15 - 12:50
(GMT-3)

#### Laurence PRUVOST

Université Paris-Saclay/CNRS-France

### Four-wave mixing in atomic vapours with optical vórtices

An optical vortex is a laser beam with a helical wavefront. Its main property is a twisted Poynting vector and an associated orbital angular momentum (OAM) of the photon whose value is quantized by an integer $\ell$ which is the direction and number of the helix branches. The OAM is one of the variables that can be used for quantum technologies.
The Recife group was a pioneer in the use and understanding of OAM in 4-wave mixing showing its transfer, storage and retrieval. I will give the evolution of the field which today leads to OAM entanglement and quantum simulation using OAM

12:50 - 13:25
(GMT-3)

#### Robin KAISER

Université de la Côte d’Azur/CNRS-France

### Photon-atom interactions

Atom-light interactions have been at the heart of follow this basic research approach and investigate collective effects in fondamental and applied science, ranging from the understanding of atomic emission lines to the invention of lasers. We scattering of light by large atomic systems. I this talk, I will present results of scattering of light by large ensembles of cold and hot atoms, with impact on atomic physics, statistical physics, quantum optics, mesoscopic physics and astrophysics.

13:25
(GMT-3)

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