Figure 1

Photomicrographs of the hexagonal-close-packed monolayer taken between crossed polarizers (indicated by $P$ and $A$) for different fields: (a) $E=0$, (b) $E=0.03\mathrm{V}/\mu \mathrm{m}$, and (c) $E=0.15\mathrm{V}/\mu \mathrm{m}$. (d) The schemes show the experimental geometry. Anisotropy in the drop shape fixes the polar axis of the drops in the$x\mathrm{\text{−}}y$ plane in the absence of an $E$ field. For $E\ne 0$ the axis rotates through an angle $\alpha$ reducing the birefringence of the drops as indicated by the color change. For the diffraction experiment, light is incident along $\mathbf{k}$ with polarization direction ${\mathbf{E}}_{\omega }$ along the drop polar axis. At $E=0$ the effective refractive index for ${\mathbf{E}}_{\omega }$ equals the extraordinary index of refraction $n_e$ of the liquid crystal.Reuse & Permissions

Figure 2

Polarized optical microscopy observations of an individual drop during application and after removal of an electric field. The photomicrographs in (a)–(c) show a sequence of images taken after application of an $E=0.13\mathrm{V}/\mu \mathrm{m}$ field. The times are (a) $t=0$, (b) $t=1/30\mathrm{s}$, and (c) $t=4/30\mathrm{s}$. Sketched below each of the photomicrographs, (d)–(f), is a scheme depicting the director structure inside the drop during switching. A time sequence during the relaxation after removal of an $E=2.1\mathrm{V}/\mu \mathrm{m}$ field is shown in the photomicrographs in (g)–(i). The time after removal of the field are (g) $t=0\mathrm{s}$, (h) $t=1/30\mathrm{s}$, and (i) $t=2/30\mathrm{s}$. The system continues to relax back to the state shown in (a) after $t=0.85\mathrm{s}$. Image (g) appears black under conditions similar to the other photomicrographs and has been electronically enhanced for clarity.Reuse & Permissions

Figure 3

Time dependence of the transmitted intensity and orientation of droplet axis. (a) The arrows indicate the times at which the square wave voltage signal is turned off from ($A$) $0.12\mathrm{V}/\mu \mathrm{m}$, ($B$) $0.056\mathrm{V}/\mu \mathrm{m}$, ($C$) $0.041\mathrm{V}/\mu \mathrm{m}$, and ($D$) $0.026\mathrm{V}/\mu \mathrm{m}$. The number of extremes in the transmitted signal is reduced as the applied field decreases. (b) Square symbols, on times, indicate the total time for the film to become transparent after an external field is applied and the round symbols, off times, give the time for the diffraction pattern, shown in (c), to return upon removal of the field. The jump in the relaxation time at high fields, see the arrow in (b), occurs when the relaxation process switches from the simple movement of two disclinations, (d), to a coarsening followed by the movement of the final pair, (e).Reuse & Permissions