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Journal of Modern Optics

Determining the density matrix of a molecular beam using a longitudinal matter wave interferometer

Al-Amin Dhirani, David A. Kokorowski, Richard A. Rubenstein, Troy D. Hammond, Bernd Rohwedder, Edward T. Smith, Anthony D. Roberts, David E. Pritchard

Published Nov 1, 1997• 14 citations
Publisher

Abstract

Two separated oscillatory fields, if tuned to different frequencies, can generate or interrogate longitudinal momentum coherences in a beam of two-state particles. We demonstrate that use of differentially detuned separated oscillatory fields is an efficient method to determine the longitudinal density matrix of a particle beam.
DOI
10.1080/09500349708231903

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We provide a fully quantal treatment of a beam of two-state particles interacting with temporally oscillating potentials, and propose a number of longitudinal atom optics devices. A single oscillatory potential, in coupling the two internal states, generally entangles each with a different longitudinal momentum. An oscillatory potential can also act as an amplitude modulator, creating momentum coherences within a single internal state. Two successive oscillatory fields (DSOF's), if differentially detuned, can couple an initially monochromatic state to a coherent momentum superposition, or alternatively may be used to detect a pre-existing momentum superposition. DSOF's can create amplitude modulation which, despite the presence of a broad velocity distribution, rephases at a selected distance downstream of the device. Phase modulation generates coherent momentum sidebands which can evolve into amplitude modulation at a particular location downstream.