The phased polaron beam is an extremely powerful directed energy weapon that fires a beam of polarons at the target.

Jem'Hadar fighters were equipped with phased polaron beams, which had devastating effects on Federation, Romulan and Cardassian shields after they were first encountered in 2370. (DS9: "The Jem'Hadar", "The Die is Cast")

In 2372, while on a diplomatic mission to negotiate a trade agreement between the Karemma and the Ferengi, the Defiant was attacked, and repelled enemy fire. (DS9: "Starship Down") The Dominion did not become aware of the shield modifications until the Second Battle of Deep Space 9 in 2373, when Dominion officers were surprised to see Deep Space 9's shields holding. (DS9: "Call to Arms").

Jem'Hadar polaron rifles include an anticoagulant in the energy stream. This prevents any non-fatal rifle wounds from healing, forcing the enemy to devote resources into caring for them. (DS9: "The Ship", "Change of Heart") These weapons were replaced by plasma rifles in late 2375. (DS9: "Tacking Into the Wind")