Fresh cut for the experiment
At LP2N
Cold Atoms in Bordeaux
Since its early development in the beginning of the 20th century, the quantum theory has reached tremendous success in describing the microscopic world. As a ground breaking example this theory perfectly describes the behavior of single to a few atoms coupled to an electromagnetic (EM) field (2012 Nobel Prize). Despite this success, the full understanding of larger systems known as N body correlated systems still remains to be unveiled. This is particularly the case in low temperature electronic solid state systems for which the temperature is far below the Fermi temperature (T/TF<0.005). Such regime is still mostly understood but we expect that the dynamics of the system will be driven by quantum correlations.
Two-dimensional electron gases (2DEG) that consist of electrons moving in a single atomic layer belong to this class of un-understood N-bodies correlated systems. For the quantum physics and condensed matter communities, they represent a great interest that could enlighten the conduction properties of graphene, the behavior of cuprates and other high-Tc superconductors or the properties of edge states in topological insulators. In this framework, the development of ultra-cold atom control offers toy-model systems to study the quantum properties of matter. In our project, we develop such a type of 2D ultra-cold atom quantum simulator using a new, original and challenging hybrid quantum system made of ultra-cold atoms and near field nano-structured EM potentials. Compared to usual far-field simulators, our apparatus allows us to raise all the energy scale at play in the underlying phenomena (nowadays a limiting factor) and to engineer novel types of long range interactions and band diagrams that should unveil these complex quantum phases.
AUFRONS - Ultra-cold atoms in a nano-structured optical lattice
Experimental Setup
2DMOT
3DMOT
The experimental sequence
It's the heart of the experiment where a pressure of 10e-10 mbar is reached. The following describes the experimental sequence to get cold atoms:
2DMOT and 3DMOT: Rubidium atoms are pushed from the 2DMOT chamber to the main 3DMOT chamber. Then, atoms are trapped using a Magneto-Optical Trap using a quadrupole field gradient and 5 collimators for the cooling at -2.7Γ and repumper beams. We load about 3.2e9 atoms in 12 seconds.
CMOT: Then, we realise a Compressed MOT by detuning the cooling frequency to -10Γ and increasing the magnetic gradient.
MOLASSES: After that, comes Molasses where the gradient is set to zero and the detuning is increased to -21Γ. At this stage, we know the residual magnetic offset and correct it with the compensation coils in the three directions. At the end, the final temperature is about 40 μK.
OPTICAL PUMPING: atoms are typically prepared in the state F=1, mF=-1 by using repumper and depumper beams σ- polarised before loading them in the magnetic trap.
MAGNETIC TRAP: usually 1.4e9 atoms are trapped by rising abruptly the quadrupole field to 60 G/cm and then increasing adiabatically to 160 G/cm. The atoms are heated up to 130 μK during this process but we can proceed with the evaporation towards Bose Einstein Condensates.
RF EVAPORATION: 2.3 seconds of radiofrequency evaporation enables us to get 9e7 atoms at 35/40 μK.
HYBRID CROSSED DIPOLE TRAP: 2e7 atoms are loaded by decompressing the magnetic trap until gravity compensation, and 1064nm dipole traps are turned on to finish the evaporation optically.
BECs of 1e6 atoms are obtained after 3s evaporation:
Thermal distribution: Thermal cloud, T>Tc
Double structure: BEC and thermal cloud, T=Tc
TOF=16ms
The optical bench
All laser beams at 780nm comes from a laser diode whose the feedback is achieved by saturated absorption on an atomic transition of Rb87 and two others slave laser diodes that are phase locked using beats with the Master.
Those three lasers are distributed on a separable optical table to get all the necessary beams on the experiment.
On the picture, the three laser beams are inserted from the top and manipulated with waveplates, mirrors, polarised beam splitters, shutters and acousto-optic modulators (to be fast). They are fibre coupled and sent to the experiment.
The imaging system
Once our lattice and BEC have been set up, we want to image the position of each site of the lattice. In other words a sub-wavelength resolution is needed to overcome the diffraction limit.
To this end, two energy states of Rb87 are modulated using the Stark effect such that only a few atoms can be excited on resonance for a given laser frequency. Scanning in frequency the imaging laser enables us to scan in position different atoms in the lattice and then reconstruct the site positions.
Current work
We are implementing a setup to have an optical lattice at 1529nm (5P-4D transition) to repump a tunable volume of atoms and get sub-wavelength details of the BEC.
07/2019
lattice spacing is 7.7 um
Latest News
People
AUFRONS- Team Members
Simon Bernon
Principal Investigator
Main research focus :
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Hybrid quantum system
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Exotic quantum phases simulated by atoms in nanolattice potentials
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Strong atom field interaction in confined geometries
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Laser spectroscopy of molecular vibrational transitions
Lecturer in
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Atomic Physics
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Quantum Gas and Quantum Optics
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Numerical Simulation of Physical systems
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Innovation and Entrepreneurship program
Collaborators
Philippe Bouyer
Now coordinator of Quantum Delta - Quantum sensor program
Vincent Mancois
Former PostDoc
Now at NTU Singapor
Non Equilibrium phase transition in long range interacting systems
Romain Veyron
Former PhD
Now at ICFO - Barcelone
Collaboration on multilevel dynamics of doubly dressed states potentials
Jean-Baptiste Gérent
Former PhD
Collaboration on subwavelength imaging and atom-chip design
Phd Students
Ruiyang Huang
PhD on doubly dressed state trapping and subwavelength imaging
Eliott Beraud
PhD on atom nano-photonics coupling
Alumni
PostDoc and PhD
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Guillaume Baclet
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PhD Student, 2019-2023
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Jean-Baptiste Gérent
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PhD Student, 2019-2023
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Romain Veyron
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PhD student, 2018-2021
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Vincent Mancois
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PostDoc 2018-2021
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Maxime Bellouvet
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PhD student, 2015-2018
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Caroline Busquet
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PhD student, 2014-2017
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Working now at Alphanov
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Jinyi Zhang
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Post-doc, 2014-2016
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Hugo Salvador Vasquez Bullon
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PhD student, 2012-2016
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Working now at Capgemini
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Leticia Tarruell
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Junior CNRS Researcher, 2012-2013
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Now group leader at The Institute of Photonic Sciences in the Quantum Gases Group, Barcelona
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Master students
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Ayoub Yaquine
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M1 Student in numerical electronic, 2023
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Mohammed Elhaouati
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M1 Student in numerical electronic, 2023
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Christophe Ye
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M1 Student in optical mode simulation 2022
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Victor Villain
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IUT Student on DDS programming 2021
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Etienne Meffre
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M2 Student on spin texture simulation 2021
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Anwar Benjana
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M1 Student on laser system 2020
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Guillaume Baclet
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M2 on Acetylene laser lock 2019
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Jean-Baptiste Gérent
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M2 on Atom-chip development 2019
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Romain Veyron
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Predoc position, 2017-2018
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Maxime Bellouvet
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M1 student, 2015
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M2 student, 2016
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Caroline Busquet
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M2 student, 2014
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Publications
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Quantitative absorption imaging of optically dense effective two-level systems, Romain Veyron, Vincent Mancois, Jean-Baptiste Gerent, Guillaume Baclet, Philippe Bouyer, Simon Bernon, Phys. Rev. Research 4, 033033 (2022). arXiv:2110.12505
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Effective two-level approximation of a multi-level system driven by coherent and incoherent fields, Romain Veyron, Vincent Mancois, Jean-Baptiste Gerent, Guillaume Baclet, Philippe Bouyer, Simon Bernon, Phys. Rev. A 105, 043105 (2022). arXiv:2110.08894
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Compact cold atom clock for on-board timebase: tests in reduced gravity, Mehdi Langlois, Jean-Françcois Schaff, Luigi De Sarlo, Simon Bernon, David Holleville, Noël Dimarcq, Physical Review APPLIED 10, 064007 (2018). arXiv:1812.01658
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Doubly-dressed states for near-field trapping and subwavelength lattice structuration. Maxime Bellouvet, Caroline Busquet, Jinyi Zhang, Philippe Lalanne, Philippe Bouyer, Simon Bernon. Phys. Rev. A 98, 023429 (2018). arXiv:1710.05696
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Interaction between atoms and slow light: a waveguide-design study. Xiaorun Zang, Jianji Yang, Rémi Faggiani, Christopher Gill, Plamen G. Petrov, Jean-Paul Hugonin, Kevin Vynck, Simon Bernon, Philippe Bouyer, Vincent Boyer, Philippe Lalanne. Phys. Rev. Applied 5, 024003 (2016). arXiv:1509.08492