  We propose an experimental scheme to study spin-orbit coupling effects in a
of two-dimensional (2D) Fermi atomic gas cloud by coupling its internal
electronic states (pseudospins) to radiation in a delta configuration. The
induced spin-orbit coupling can be of the Dresselhaus and Rashba type with and
without a Zeeman term. We show that the optically induced spin-orbit coupling
can lead to a spin-dependent effective mass under appropriate condition, with
one of them able to be tuned between positive and negative effective mass. As a
direct observable we show that in the expansion dynamics of the atomic cloud
the initial atomic cloud splits into two clouds for the positive effective mass
case regime, and into four clouds for the negative effective mass regime.
