Abstract

Bose-Einstein condensates (BEC) serve as a model system for the study of the dynamic and spectroscopic response of a quantum system to momentum excitation. However, high -resolution spectroscopy of BEC has suffered from various finite-size (Doppler broadening) and inhomogeneous density effects [1]. We propose and demonstrate experimentally [2] a momentum space echo method using two and four -photon Bragg pulses, in order to overcome these broadening mechanisms. This method is pre sented in Fig. 1, where the excitation scheme and resulting populations in momentum space are shown. We demonstrate this scheme experimentally by using a four -photon echo pulse to reflect the initi ally populated excitations. The spectroscopic response of t he echo pulse is narrower than that of a regular Bragg pulse, as shown in Fig. 2.

© 2004 Optical Society of America