Short for PHAsed Energy Rectification, Phasers have been the weapon of choice within the Federation since around 2265. Phasers work by releasing a vast amount of energy using the rapid nadion effect. Rapid nadions are short lived subatomic particles which can liberate and transfer strong nuclear forces within a class of crystals called fushigi-no-umi when energy is channeled through the crystal.
A relatively new development in phaser technology, the Type U Pulse Phaser is the most combat-focused development of the phaser to date. They combine large, nearly flawless emitter crystals with rapid-discharge EPS banks and high-speed beam focusing coils. The system allows the charge to be stored in the coils for a few nanoseconds, then release it as a layered pulse. Due to the nature of the pulse, shields and armour have a harder time dispersing the pulse, resulting in more damage to the target.
Pulse phasers were first deployed on the USS Defiant, where they managed to cause significant damage to Jem Hadar fighters in a short space of time.