A laser includes a gain medium located in a laser resonator. The gain medium
plane polarized radiation plane polarized in a first polarization orientation.
An electro-optical switch is located in the resonator. When the switch is activated
the polarization plane of the laser radiation is rotated to a second orientation
after making a forward and a reverse pass through the optical switch. When the
switch is deactivated, the polarization orientation of the forward and reverse
transmitted laser radiation remains about the same. A polarization selective device
is located in the resonator between the electro-optical switch and the gain medium.
The polarization selective device is arranged to permit circulation in the resonator
of laser radiation in the first polarization orientation, and to restrict circulation
of laser radiation in the second polarization orientation. The Gain medium is energized
and the switch activated to allow energy to build in the gain medium. The switch
is then deactivated to allow laser radiation to circulate in the resonator and
deliver a laser pulse. A method of activating the switch by a sequence of DC pulses