The nematic droplets with director configurations intermediate between the bipolar and radial structures have been investigated experimentally and theoretically. The liquid crystal 4'-n-pentyl-4-cyanobiphenyl (5CB) with a variable addition of the lecithin dispersed in polyvinylbutyral has been used. The characteristic textures of the droplets formed at various lecithin contents have been examined using polarizing microscope both in the crossed polarizers and without analyzer. The computer simulation has been performed for proper ordering of the director in spherical nematic droplets by minimizing the free energy in the one-constant approximation. The inhomogeneous boundary conditions with strong anchoring of the molecules at the interface have been used. The distribution of the anchoring angle at the droplet surface has been estimated based on analysis of observed patterns. The simulated textures of the droplets under crossed polarizers are shown to compare well with the experimental ones.

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An electrically tunable and polarizer-free photonic device is developed using a one-dimensional photonic crystal (PC) infiltrated with dual-frequency cholesteric liquid crystal (DFCLC) as a defect layer. The PC/DFCLC hybrid cell allows the employment of various frequency-modulated voltage pulses to regulate defect modes and switch between stable states. This device possesses many alluring features such as rapid bistable switching, intensity tunability, and wavelength tunability in the defect modes, and it requires no polarizers. It can be used as a filter, fast-speed shutter, or light-intensity modulator.

We demonstrate in this paper an electrically tunable photonic device based on one-dimensional photonic crystal (PC) infiltrated with polymer-stabilized cholesteric texture (PSCT) as a central defect layer. With the hybrid PC/PSCT structure, not only is the wavelength of each defect mode switchable among three major stable states by various appropriate frequency-modulated voltage pulses, but also the intensity can be electrically tuned in multi-metastable states. As a result, an electrically controllable multichannel photonic device with several alluring features is proposed. It is wavelength-switchable, intensity-tunable, and polarizer-free and possesses optical tristability in the defect modes to reduce power consumption.