An electro-optic deflector 51 has an electro-optic material body 519 through which an optical beam 46 is passed. The deflector has no more than three longitudinal electrodes, of which no more than two electrodes 511, 512 have arcuate transverse cross-sections. The electrodes are arranged to create an electric field substantially transverse to a direction of the optical beam to deflect the optical beam passing between the electrodes. The electro-optic deflector has particular application in a Q-switched laser for generating sub-nanosecond optical pulses.