Cooled electrooptic deflector made of a DKDP crystal

An investigation was made of a cooled prism deflector of the transmission type made of a DKDP crystal. The problems of thermal stabilization of crystals and elimination of the influence of piezoelectric deformations of the crystal on the operation of the deflector, as well as protection of the surfaces from damage and attainment of both large angles of deflection and a large number of resolved elements were tackled. A special immersion liquid capable of retaining its properties down to – 70 °C was developed. The use of this liquid made it easier to achieve high deflection angles and to protect surfaces. An angle of deflection of ~ 4° was obtained in a field of 20 kV/cm, which ensured that up to 350 elements were resolved when the beam diameter was 5 mm and the wavelength was λ = 1.06 μm. The deflection angles could be increased by using a series of consecutive deflector cells and by bipolar control of these cells. The ultimate potentialities of the deflectors were estimated from the number of the resolved elements.