  We propose a new type of a chiral metamaterial based on an ensemble of
artificial molecules formed by three identical quantum-dots in a triangular
arrangement. A static magnetic field oriented perpendicular to the plane breaks
mirror symmetry, rendering the molecules sensitive to the circular polarization
of light. By varying the orientation and magnitude of the magnetic field one
can control the polarization and frequency of the emission spectrum. We
identify a threshold frequency, {\Omega}, above which we find strong
birefringence. In addition, a Kerr rotation and circularly polarized lasing
action can be implemented. We investigate the single-molecule lasing properties
for different energy-level arrangements and demonstrate the possibility of
circular polarization conversion. Finally, we analyze the effect of weak stray
electric fields or deviations from the equilateral triangular geometry.
