Abstract We Introduction Nematic cells are widely used as optical retarders in various applications where 0 ε is the electric constant, 1 γ is the rotational viscosity of the nematic liquid crystal, ∆ε=ε II -ε ⊥ is the dielectric anisotropy, ε II and ε ⊥ are the principal dielectric permittivities referred to the nematic director, threshold value of the applied voltage, K is the characteristic elastic constant. According to Eq.(1), one can decrease τ on by increasing the applied voltage. However, the relaxation time τ off depends only on the material parameters and the thickness of the cell and cannot be shortened by a higher electric field, see Eq.(2) τ off ~d 2 . The drawback is that smaller d causes smaller optical retardation (the optical path difference for ordinary and extraordinary waves) ∆L, as ∆L~d. The goal of our work was to resolve contradictory requirements of fast (sub-millisecond) switching and the broad range of switched optical retardations (∆L ≥1µm). Fast Switching Dual-Frequency Liquid Crystal Optical Retarder We use the so-called dual-frequency nematic materials in cells with a high pretilt angle (α≈45 degrees) driven by a sequence of electric pulses of different frequency and amplitude. We assembled nematic cells with an anti-parallel fashion from plates with a high pretilt angle, which was achieved by oblique deposition of SiO layers We used the optical setup with the cell placed between two crossed polarizer prisms to measure the time evolution of the optical response of the cell
