Fig. 1. (a) Frequency dependence of dielectric constants (ε_∥ and ε_⊥) of the DFNLC DP002-026 at various temperatures: 26°C (blue filled circle), 28°C (orange open square), 30°C (green filled rhombus), 32°C (red open triangle), 34°C (purple filled inverted triangle), 36°C (brown open circle), and 38°C (blue filled square). (b) Schematic illustration of the experimental setup for diffraction characterization. A cell is equipped in the hot stage and probed with a linearly polarized laser beam.

Fig. 2. POM images and the corresponding phase diagram of pattern formation for the DFNLC DP002-026. (a) Pattern generation as the field frequency varies from 28 kHz to 40 kHz at the voltage U = 16.1 V, the cell thickness d = 8 µm, and T = 30°C. (b) Pattern generation as the field frequency varies from 25 V to 0 V at the frequency f = 40 kHz, the cell thickness d = 8 µm, 0 V, and T = 30°C. (c) The corresponding phase diagram of pattern formation during voltage decrease for the DFNLC DP002-026 in the cell of thickness d = 8 µm and T = 30°C. The patterns are recorded using crossed polarizers and a quarter waveplate placed at 45° with respect to P. The initial nematic director aligns horizontally.

Fig. 3. Dependences of lateral rolls on the voltage and the dielectric anisotropy of the DFNLC DP002-026. Lateral rolls and corresponding diffraction phenomena at the voltages of amplitude (a) U = 7.5 V, (b) U = 11 V, (c) U = 15 V, and (d) transmitted light intensity versus x. (e) The voltage dependence of the lattice period P_x. (f) P_x (blue filled circles) and L_x (red open circles) as a function of the voltage frequency. (g) P_x as a function of Δε. T = 30°C, d = 8.0 µm, and the initial direction of the director is horizontal.

Fig. 4. Dependences of longitudinal rolls on the voltage and the dielectric anisotropy of the DFNLC DP002-026. Longitudinal rolls and corresponding diffraction phenomena at the voltage of amplitudes (a) U = 14 V, (b) U = 17 V, (c) U = 20.5 V, and (d) transmitted light intensity versus y. (e) The voltage dependence of the lattice period P_y. (f) P_y (orange filled circles) and L_y (green open circles) as a function of the voltage frequency. (g) P_y as a function of Δε. T = 30°C, d = 8.0 µm, and the initial direction of the director is horizontal.

Fig. 5. Dependences of square-grid patterns on the voltage and the dielectric anisotropy of the DFNLC DP002-026. The patterns and corresponding diffraction at the voltages of amplitude (a) U = 17 V, (b) U = 20 V, (c) U = 25 V, and (d) transmitted light intensity versus y. (e) The voltage dependence of the lattice period P_x and P_y. (f) P_x, P_y, and L_x, L_y as functions of the voltage frequency. (g) P_y as a function of Δε. T = 30°C, d = 8.0 µm, and the initial direction of the director is horizontal.