Shuxin Liu

Polymer-stabilized blue-phase liquid crystal grating cured with interfered visible light

In this paper, we demonstrate a holographic polymer-stabilized blue-phase liquid crystal grating fabricated using a visible laser. As blue phase is stabilized by the interfered light, polymer-concentration gradient is achieved simultaneously. With the application of a uniform vertical electric field, periodic index distribution is obtained due to polymer-concentration gradient. The grating exhibits several attractive features such as polarization-independency, a broad temperature range, sub-millisecond response, simple fabrication, and low cost, thus holding great potential for photonics applications.

High-Efficiency Video-Rate Holographic Display Using Quantum Dot Doped Liquid Crystal

We demonstrate a real-time holographic display using quantum-dot doped liquid crystal with a build-up time of several to tens of milliseconds, and the maximum diffraction efficiency is measured up to 30%. Holographic videos of red, green, and blue colors at a refresh rate of 60 Hz are realized. The dependences of response time on the recording intensity, applied voltage, and grating period are investigated.

Polymer-Stabilized Blue-Phase Liquid Crystal Fresnel Lens Cured With Patterned Light Using a Spatial Light Modulator

In this paper, we use a dynamic mask lithography system to fabricate a polymer-stabilized blue-phase Fresnel lens. Fresnel-zone patterned light is directly generated by a programmable spatial light modulator and then projected onto the blue phase precursor. As blue phase is cured, a Fresnel-zone refractive index distribution is achieved simultaneously. The fabricated Fresnel lens features polarization-insensitivity, a broad temperature range, submillisecond response and high spatial frequency. With easy fabrication and programmable flexibility, this method has great potential for various optical applications.

Transmissive and Transflective Blue-Phase LCDs With Double-Layer IPS Electrodes

A double-layer in-plane-switching electrode design is proposed for transmissive and transflective blue-phase liquid crystal displays. The new design significantly reduces the operating voltage in transmissive display by 60%; in transflective displays where the bottom-layer electrodes are made of conductive reflectors, it increases transmittance to 98%, achieves single gamma driving and enhances sunlight readability.

Polymer network liquid crystal grating/Fresnel lens fabricated by holography

ABSTRACT In this article, polymer network liquid crystal (PNLC) grating/Fresnel lens is fabricated by holography. The exposure light pattern for the grating is obtained by interfering two planar wave fronts, while the Fresnel pattern is achieved by interfering a planar wave front and a spherical wave front. Owing to the alignment effect and anchoring power of polymer network, the holographic PNLC grating achieves improved diffraction efficiency, and remarkably reduced operation voltage (reduced by 80%) compared with holographic polymer-dispersed-liquid-crystal and holographic polymer-stabilised blue-phase liquid-crystal gratings, while maintaining submillisecond response. Moreover, it achieves high spatial frequency with a 2-μm grating period, thanks to the holographic fabrication. The holographic PNLC Fresnel lens also exhibits attractive electro-optical properties. Graphical Abstract

Highly photorefractive hybrid liquid crystal device for a video-rate holographic display.

In this paper, we demonstrate a dynamic holographic display in a quantum dot (ZnS/InP) doped liquid crystal device, where one of the interior cell surfaces is covered by a ZnSe layer. Such a hybrid device shows substantially improved photorefractive sensitivity of 2.2 cm3/J, which is almost 300 times larger than that in ZnS/InP doped liquid crystal device without the ZnSe layer. The holographic grating can form at intensities as low as ~0.8 mW/cm2, and exhibit a fast optical response of several to tens of milliseconds. Exploiting the superior performances of photosensitivity and fast response of this device, we obtain dynamic holographic videos of red, green, and blue colors, as well as a reconstructed image of high gray-scale fidelity.

Holographic display and storage based on photo-responsive liquid crystals

ABSTRACT Liquid crystals (LCs) are widely used in nonlinear optics because of their sensitive responses to optical stimulation. Combined with other optoelectronic materials such as azo dyes, quantum dots (QDs), etc., LCs show very large optical nonlinearity which makes them suitable for applications in optical information processing, including holographic display and holographic storage. In this review, we present an overview of recent efforts on holographic display and storage based on liquid crystalline materials. Emphasis is placed on the dynamic holographic display which uses fast-response LCs doped with azo dye and QD. In this application, we discuss how to improve the response speed, resolution, and diffraction efficiency of liquid crystalline materials to realize high frame rate, large-size and high-brightness holographic displays. Some LC materials for holographic storage are also introduced, including polymer-dispersed liquid crystals, blue-phase liquid crystals, and azobenzene polymer liquid crystals, which have permanent response to light stimulation. The mechanisms of optical nonlinearities are discussed in detail, as a foundation for the physical process of LC-based holographic display and storage.

Liquid crystal true 3D displays for augmented reality applications

Augmented reality (AR) technology, which integrates virtual computer-generated information into the real world scene, is believed to be the next-generation human-machine interface. However, most AR products adopt stereoscopic 3D display technique, which causes the accommodation-vergence conflict. To solve this problem, we have proposed two approaches. The first is a multi-planar volumetric display using fast switching polymer-stabilized liquid crystal (PSLC) films. By rapidly switching the films between scattering and transparent states while synchronizing with a high-speed projector, the 2D slices of a 3D volume could be displayed in time sequence. We delved into the research on developing high-performance PSLC films in both normal mode and reverse mode; moreover, we also realized the demonstration of four-depth AR images with correct accommodation cues. For the second approach, we realized a holographic AR display using digital blazed gratings and a 4f system to eliminate zero-order and higher-order noise. With a 4k liquid crystal on silicon device, we achieved a field of view (FOV) of 32 deg. Moreover, we designed a compact waveguidebased holographic 3D display. In the design, there are two holographic optical elements (HOEs), each of which functions as a diffractive grating and a Fresnel lens. Because of the grating effect, holographic 3D image light is coupled into and decoupled out of the waveguide by modifying incident angles. Because of the lens effect, the collimated zero order light is focused at a point, and got filtered out. The optical power of the second HOE also helps enlarge FOV.