  The transfer of orbital angular momentum from an optical vortex to an atomic
Bose-Einstein condensate changes the vorticity of the condensate. The spatial
mismatch between initial and final center-of-mass wavefunctions of the
condensate influences significantly the two-photon optical dipole transition
between corresponding states. We show that the transition rate depends on the
handedness of the optical orbital angular momentum leading to optical
manipulation of matter-wave vortices and circular dichroism-like effect. Based
on this effect, we propose a method to detect the presence and sign of
matter-wave vortex of atomic superfluids. Only a portion of the condensate is
used in the proposed detection method leaving the rest in its initial state.
