A formal geometrical optics approach (GOA) to the optics of nematic liquid crystals whose optic axis (director) varies in more than one dimension is described. The GOA is applied to the propagation of light through liquid crystal films whose director varies in three spatial dimensions. As an example, the GOA is applied to the calculation of light transmittance for the case of a liquid crystal c...

In the sensing applications of optical fiber grating, it is necessary to reduce the transmission-type polarization dependence to isolate the sensing parameter. It is experimentally shown that the polarization-dependent spectrum of acousto-optic long-period fiber grating sensors can be suppressed in the transmission port of a π-shifted Sagnac loop interferometer. General expressions for the tran...

We develop a refraction model to analyze the electro-optic effects of an in-plane-switching blue phase liquid crystal (IPS-BPLC) cell. Good agreement with experiment is obtained. Based on this model, we optimize the parameters affecting the electro-optics of IPS-BPLC, such as electrode dimension, saturated induced birefringence, saturation electric field, and cell gap. An IPS-BPLC with low oper...

Galvanostatic electrodeposition was used to produce transparent and amorphous WO3 films that showed color changes from clear to blue in response to the applied potential of ±1.0 V. The 61% in transmittance variation was measured at wavelength of 633 nm. The roughness of 16.7 nm was obtained by atomic force microscopy (AFM). The scanning electron microscopy (SEM) evidenced homogeneous morphology...

We propose a new in-plane switching (IPS) nematic liquid crystal (LC) mode which uses a twist effect with a hybrid LC alignment and interdigitated electrodes as an approach for a high brightness. This is optimized to a normally white mode to minimize loss of transmittance at the electrode compared to the conventional IPS mode. The proposed mode shows an excellent dark state because the bulk LCs...

We analyze the transmission characteristics of a Sagnac loop interferometer containing a polarization-dependent loss element and lossless polarization-converting elements by use of Jones matrices. We show that polarization independence in the transmission mode can be achieved in such a configuration and that maximum transmittance occurs when a half-wave plate is used for the polarization-conver...