• 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)