  Orbital angular momentum (OAM) carried by helical light beams is an unbounded
degree of freedom of photons that offers a promising playground in modern
photonics. So far, integrated sources of coherent light carrying OAM are based
on resonators whose design imposes a single, non-tailorable chirality of the
wavefront (i.e. clockwise or counter clockwise vortices). Here, we propose and
demonstrate the realization of an integrated microlaser where the chirality of
the wavefront can be optically controlled. Importantly, the scheme that we use,
based on an effective spin-orbit coupling of photons in a semiconductor
microcavity, can be extended to different laser architectures, thus paving the
way to the realization of a new generation of OAM microlasers with tunable
chirality.
