Comparison of atom interferometry with laser interferometry for gravitational wave observations in space

Proposals were made earlier in 2008 to use atom interferometry based on Raman transitions for gravitational wave observations in space. Recently, Graham et al. have suggested a new atom interferometry method for such observations based on laser-induced single-photon transitions on highly forbidden optical transitions such as those used in recently developed optical clocks. However, a number of additional requirements that are not discussed by Graham et al. have to be considered if the sensitivity level they suggest is to be reached. When all of the requirements are considered, it appears that such an atom interferometry mission would be much more complex than a laser interferometry mission with better overall sensitivity.