A laser is disclosed which includes a gain medium, a switch element, and a pulse controller. In one embodiment laser light of differing polarizations pass along respective paths and a pulsed laser output is generated via an electro-optical element. In another embodiment light of differing polarizations passes in differing directions through a cyclical path. The invention can make use of a prism-shaped polarizer having a polarization selection face and two further faces. Yet further initial pulses can be controlled to reduce energy, for example by progressively increasing the period or amplitude of successive pulses. As a result an efficient and high power laser apparatus is realized.