• Diffraction of Atomic de Broglie Waves
• Atom Beam Interferometer Experiments
Atom Optics and Atom InterferometryAlex Cronin
U.A. Physics
Atom Beam Diffraction
grating
dBnDiffractio d
Cou
nt R
ate
Period = 100 nm
Support bars
Gratings for Atom Waves
Material: silicon nitride
Front View
2 2 cos( )gFlux U U L L U L ik x
( ) gik xi ky wte Upper Lower e
Atom Interferometer
Second GratingOptical Grating
Atom Interferometer
Objective: Pioneer new techniques using matter-wave interference to make precision measurements.
• Study quantum decoherence,• Matter-wave index of refraction,• Atomic polarizability.
Approach: 3 nano-fabricated diffraction gratings.
• Mach-Zhender interferometer for atom-waves..
Interferometer Performance:
• Up to 50% contrast.• Small phase drift (< 2 rad / hr).• Layout is easily changed for new experiments.• Macroscopic (100 m) path separation.
Decoherence due to Photon Scattering PRL 86: 2191 (2001)
• Two interpretations: which-way & phase diffusion• Demonstration of scaling laws• Easy to calculate ab initio (& agrees with experiment)
Each atom scatters:
Contrast vs. Separation (d)
