  The strongly correlated charge density wave (CDW) phase of 1T-TiSe$_2$ is
being extensively researched to verify the claims of a unique chiral order due
to the presence of three equivalent Fermi wavevectors involved in the CDW
formation. Characterization of the symmetries is therefore critical to
understand the origin of their intriguing properties but can be complicated by
the coupling of the electronic and lattice degrees of freedom. Here we use
continuous wave laser excitation to probe the symmetries of TiSe$_2$ using the
circular photogalvanic effect with very high sensitivity. We observe that the
ground state of the CDW phase is achiral. However, laser excitation above a
threshold intensity transforms TiSe$_2$ into a chiral phase in a nonequilibrium
steady state, which changes the electronic correlations in the stacking
direction of the layered material. The inherent sensitivity of the
photogalvanic technique provides clear evidence of the different optically
driven phases of 1T-TiSe$_2$, as well as emphasizes the interplay of electronic
and lattice degrees of freedom in this system under optical excitation. Our
work demonstrates that optically induced phase change can occur at extremely
low optical intensities in strongly correlated materials, providing a pathway
for future studies to engineer new phases using light.
