Very slow atomic diffraction through one and several nanogratings

We propose a cold atoms experiment where diffraction pictures of slow atomic beams are measured through a 100 nm period nanograting. During the passage inside the slits, atoms experience Casimir-Polder atom surface potential and the diffraction picture is strongly enhanced. The theoretical description of the potential is then naturally accurate.
 

Atom surface interaction is nowadays discussed as Casimir-Polder potential that takes into account both van der Waals (non-retarded) and Casimir (retarded) potentials. Historically separated for their different power laws (1/z³ vs 1/z⁴) and distances to surface interaction (up to few 100 nm vs more than 500 nm), both potentials were hardly differentiated. Our original experimental configuration allows us to constrain the theoretical potential with a worldwide competitive accuracy down to less than 10%. Such a large accuracy gives the opportunity to discriminate between van der Waals and Casimir-Polder potential at a small distance of 50 nm.
 

One goal of the internship and further the PhD is to add one nanograting few cm after the first one. This unique situation will study the atomic quantum random walk (QRW) through a large order beam splitter (up to 30 coherent orders at 20 m/s). QRW is an interesting way to reproduce quantum simulation and novel quantum technologies.
The second close topic will be to produce a complete interferometer made by 3 separated nanogratings. Such a design has already been done with fast atomic beams. Using cold atoms will make the interferometer 10 times much compact and more accurate for rotation measurements. Atomic gyrometer are intrinsically order of magnitude more accurate than optical one (gyrolaser) but extremely difficult to realize with optical gratings. A compact atomic matter interferometer might be a clever option and is asked by the community to be carefully studied.
 

Internship and PhD will be strongly experimental (vacuum, cold atoms, laser, nanotechnology) and request enthusiasm for numerical fittings and Schrödinger equation solving.
Financial support for a PhD: team’s own contracts / grant from Ecole Doctorale
 

Contact: PhD supervisor Gabriel Dutier
Team: Optique et interférométrie atomiques