Figure 7.19: Q switch action as a function of time.
Figure 7.19 describe the Q switch action as a function of time.
The active medium gain increase continuously, while the loop gain and the output power remains zero, until the Q switch is open at time t2.
The dash line in figure 7.19 describes the process in the same active medium if the Q switch were not present.
Q switch is used when a short pulse with high peak power is needed.
The payment for the high peak power is the decrease in the total energy emitted by the laser.
Q switch method is applicable only for lasers with long lifetime of the upper laser energy level.
Q switch is used in solid state lasers used for laser range finders (see section 9.3.1).