Liquid crystal photonic technology has been widely explored aiming to provide the immersive Augmented Reality (AR) experience. In this paper, we discuss the potential of using this technology to build AR waveguide displays. We start from the physical understanding of one type of the LC elements-Polarization Volume Holograms (PVH). Then we discuss the benefits/issues of using PVH as waveguide couplers. Finally, we explore the potential scale up manufacturing path of the PVH waveguides. We expect to provide the future AR glasses with small form factor, great image performance and low cost using Liquid crystal photonic technology.

In this presentation, a rubbing-free LC device fabricated with organic Single-Crystal Rubrene (SCR) substrate has been investigated. The LC orientation on SCR is determined with capillary flowing direction of LCs, the SCR-coated LC cell has a homogeneous alignment with low pretilt angle. The SCR-based LC cell performs a wider thermal tolerance than that of the PI-based cell, owing to the strong anchoring property of SCR surface. SCR-based LC cell performs a lower operation voltage, faster response time, and higher voltage holding ratio than the PI-based LC cell. A rubbing-free modal LC device based on SCR layer is under development.

Current liquid crystal technologies often rely on the use of optically thin cells and new liquid crystals. The characterisation of their parameters, such as elastic constants, including twist elastic constant and pretilt, key to control the liquid crystal response, poses several challenges. We present an optical method that successfully characterises such liquid crystal devices, is relatively simple yet a powerful probe of their static and dynamical properties. The method is demonstrated for the cells with the total phase lag smaller than 2pi and for experimental liquid crystals, where optical and dielectric properties are only partially known and for estimating K2.

We recently invented a new fluctuation microscopy principle and constructed a prototype system for observing dynamic heterogeneity of soft matter. We proved that a spatial resolution of 1 μm could be achieved with this microscope. We also prepared a nematic liquid crystal cell with a mixture of azo dye and liquid crystal. When this cell was irradiated with the blue letter "JUN" using a pattern irradiation device, the relaxation time of the irradiated area slowed down, and the relaxation time change appeared as a character pattern on the fluctuation microscope. The post-irradiation changes of the character patterns were recorded as moving images of the dynamic heterogeneity. The speed at which the pattern appears is faster than the current frame rate of video recording (~20ms).

In this talk, we will discuss the 3D depth mapping system using the Electrically Suppressed Helix Ferroelectric Liquid Crystal (ESHFLCs) Dammann grating. We used a photo-alignment approach to align the ESHFLC in patterns to create the Dammann grating profile. The ESHFLC Dammann grating projects an equal-intensity point array onto the scene from where we can extract the depth information from the scene. We achieved a cm-scale resolution using the proposed depth mapping system with a very high framerate >50k frames/s. The proposed ESHFLC Dammann grating replaces iterative scanning and enables LiDAR as a one-shot capturing system. The proposed device shows a fast-switching speed (approximately 5μs) with precise measurement of translational and rotational movement. Furthermore, low fabrication cost, lightweight, and small size make these devices suitable for modern Light Detection and Ranging (LiDAR)/3D depth mapping systems.

The Cholesteric Liquid Crystalline (CLC) phase self-organizes into a helicoidal structure that results in periodic, hierarchical organization of the LC director creating a 1-D photonic bandgap exhibiting selective reflection. We explore electrical reconfiguration of fully solid CLC elastomers (CLCEs) as dielectric elastomer actuators (DEAs). Application of an electric field causes a hypsochromic shift in the reflection resulting in a tunable electro-optic device. The electromechanical response (Maxwell stresses) in this system results in fast switching speeds, localized control, and reversible tuning. We further show how manipulation of the elastomer network has a large effect on the tunability of the electro-optic response.

This conference presentation was prepared for the Emerging Liquid Crystal Technologies XVIII conference at SPIE OPTO, 2023.

A well-known issue when dealing with lasers as illumination sources is the formation of speckle, which results in an intensity interference pattern that appears superimposed on an image. To combat the formation of speckle, we have been developing tunable liquid crystal (LC) diffusers that can reduce the appearance of speckle in a range of different display and imaging applications. Not only does this approach provide direct control of the speckle contrast, allowing it to be reduced from C = 0.7 to C = 0.07, but it does so without the need for bulky mechanical parts, moving components or expensive elements.

The main two optical aberrations seen in any imaging system are defocus and astigmatism. Traditionally, the approaches to correct both aberrations utilize the mechanical movement of fixed power spherical and cylindrical lenses. In this report, we have proposed a non-mechanical, electrically tunable optical system that can provide both focus and astigmatism power correction with an adjustable axis. The concept device is comprised of stripe electrode-based gradient refractive index liquid crystal lens. Dynamic astigmatism and focus correction are demonstrated upon the application of the electric field on the designed device. Unlike complex, bulky, and curved shape lens systems, the proposed device is flat, low cost, and low voltage driven.