Rami Arieli: "The Laser Adventure" Chapter 7 Section 3, page 2

 Single Pulse of Laser Radiation

A laser pulse can be described by plotting the laser power as a function of time (as seen in figure 7.15).

Figure 7.15: Laser power as a function of time in pulsed operation.

A good approximation for the shape of the laser pulse is the triangle (seen in figure 7.15).

The maximum emitted power is Pmax.

Most laser pulses have a steep rise (short rise time), and a longer decay.

It is common to consider the pulse duration (Delta t1/2) as its width at half maximum (0.5Pmax).

Thus, the pulse width is the time interval in which the pulse power is higher than half the maximum power:

FWHM = Full Width at Half Maximum