Kovin's photonic emitter overloads
Photonic emitters were a type of starship-mounted energy weapon utilized by some Entharan starships.
Such a weapon was utilized by the Entharan arms merchant Kovin, while attempting to evade the USS Voyager in 2374. Trying to escape a false accusation of assaulting Seven of Nine, Kovin shunted all power to his photonic emitters, causing them to overload. This resulted in his systems destabilizing, and his ship being destroyed when he attempted to fire. (VOY: "Retrospect")
It is possible photonic emitters were the weapon system that fired photon pulses on the Entharan starship.