A photonic charge (or photon charge) is a type of projectile weapon.
In 2371, Captain Kathryn Janeway proposed that USS Voyager detonate a field of photon charges between them and a large space-dwelling lifeform to discourage its attack. However, Chakotay suggested that a non-aggressive action might be more effective. (VOY: "Elogium")
The raiders of the Kazon-Nistrim are armed with photonic charges. In 2372, Seska fired a spread of photonic charges at 20% nominal yield to disable Chakotay's shuttlecraft. (VOY: "Maneuvers")
In 2375, photonic lifeforms from the "Fifth dimension" used photonic charges to attack Doctor Chaotica and his Army of Evil on Voyager's holodeck. (VOY: "Bride of Chaotica!")
When the USS Equinox EMH was switched with that of Voyager's Doctor in late 2375, he planted photonic charges throughout the sickbay holoprojectors in case he was discovered. However, the Doctor deleted his program before he could activate them. (VOY: "Equinox, Part II")