The pulse energy of a laser is the equivalent energy of a laser beam emitted over a cycle or a period. Here cycle or period refers to the time interval between the start of one pulse to the start of the next.

In the above figure, pulse energy corresponds to the shaded area in the graph, i.e. it is energy corresponding to the ON state of one cycle of a  laser pulse.

Pulse energy depends on the pulse width of the laser pulse. It increases with an increase in the pulse width. Pulse energy is expressed in joules (J).

Average power (P_avg) is that value of power when we take the energy emitted by the laser pulse to be uniformly spread over an entire cycle.

Pulse energy can be calculated from average energy as,

Here ∆t is the time duration of a period.