  Using light to manipulate materials into desired states is one of the goals
in condensed matter physics, since light control can provide ultrafast and
environmentally-friendly photonics devices. However, it is generally difficult
to realise a photo-induced phase which is not merely a higher entropy phase
corresponding to a high-temperature phase at equilibrium. Here, we report
realization of photo-induced insulator-to-metal transitions in Ta2Ni(Se1-xSx)5
including the excitonic insulator phase using time- and angle-resolved
photoemission spectroscopy. From the dynamic properties of the system, we
determine that screening of excitonic correlations plays a key role in the
timescale of the transition to the metallic phase, which supports the existence
of an excitonic-insulator phase at equilibrium. The non-equilibrium metallic
state observed unexpectedly in the direct-gap excitonic insulator opens up a
new avenue to optical band engineering in electron-hole coupled systems.
