we aren't talking about reality here, Swamp_Thing.
Phasers are based on the Rapid Nadion Effect, whereby energy is passed through a special phaser crystal resulting in a discharge of nadion particles, which are transmitters of the strong nuclear force. (often, the detection of nadion discharges is a key sign that a battle has recently taken place). Nadion particles have varying effects on the subatomic bonds of particles with which they interact, largely depending on the mass of the atom in question. To wit, dense starship hulls are more resistant to nadion discharges than is a humanoid lifeform. The disruptive effects of nadion discharges can be moderated to produce varying effects ranging from benign to extremely destructive.
Lasers use the electromagnetic force (light), which is the second strongest of the four fundamental forces. Phasers use the strong nuclear force, which is the most powerful: 137 times stronger than the electromagnetic force.