Physical Review A
We demonstrate a photon-counting technique for detecting Bragg excitation of an ultracold gas of atoms. By measuring the response of the light field to the atoms, we derive a signal independent of traditional time-of-flight atom-imaging techniques. With heterodyne detection we achieve photon shot-noise limited detection of the amplification or depletion of one of the Bragg laser beams. Photon counting for Bragg spectroscopy will be useful for strongly interacting gases where atom-imaging detection fails. In addition, this technique provides the ability to resolve the evolution of excitations as a function of pulse duration.
Pino, J. M.; Wild, R. J.; Makotyn, Philip; Jin, Deborah S.; and Cornell, Eric A., "Photon Counting for Bragg Spectroscopy of Quantum Gases" (2011). Physics Faculty Contributions. 46.