Circular-scan optical deflectors are described that do not require a polarization rotator between the deflecting elements. The elements can be of the split-prism type, in which a uniform electric field is applied to a split prism of electro-optic material, or of the quadrupole-field type, in which a linear gradient of electric field is applied, via quadrupole electrodes, to a single rod of material. When the material is potassium dihydrogen phosphate (KDP), a scan system composed of two quadrupole deflectors promises to be more attractive than a system composed of two prism deflectors, because the required drive voltage is lower, and the power dissipated within the electro-optic material is reduced by a factor of 2. At high scan frequencies, the choice will depend strongly on the relative ease of correcting the heat-induced aberrations of each system.
R. TRAMBARULO and E. A. OHM, "Improvements in Electro-Optic Circular-Scan Deflectors," J. Opt. Soc. Am. 62, 1078-1080 (1972)