We demonstrate optical methods for studying the slowly varying part of atomic center of mass wave functions, i.e., with thermal plane-wave factors removed. Utilizing continuous spatial photon echo fields and a simple lens system, the techniques determine the spatial distribution of the slowly varying wave function when the echo field is measured in the image plane. The corresponding momentum space distribution is obtained with high momentum resolution (0.1% of the photon momentum) using Fourier transform optics.

• Received 21 June 1994

DOI:https://doi.org/10.1103/PhysRevLett.74.1331