A novel electro-optic deflector based on a quadratic electro-optical potassium lithium tantalate niobate (KLTN) crystal operating slightly above the ferroelectric phase transition is presented. The new deflection scheme was based on the electric field gradient generation along the vertical axis caused by the trapezoidal geometry of the crystal. A deflection angle of 6.5 mrad was attained for a low voltage of 680 V. The deflector was used as an electro-optic modulator for implementing active Q-switching in a thulium-doped yttrium lithium fluoride (Tm:YLF) laser (1880 nm). The laser was operated at three different repetition rates of 0.4, 0.5 and 0.7 kHz, and reached high energies per pulse up to 6.9 mJ.
