LIQUID CRYSTAL POLARIZATION VOLUME HOLOGRAM FOR AUGMENTED REALITY APPLICATIONS A dissertation submitted to Kent State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy by Xiayu Feng May 2021 © Copyright All rights reserved Except for previously published materials Dissertation written by Xiayu Feng B.S., University of Science and Technology of China, Hefei, China 2015 M.S., Kent State University, Kent, USA 2018 Ph.D., Kent State University, Kent, USA 2021 Approved by Dr. Philip J. Bos , Chair, Doctoral Dissertation Committee Dr. Liang-Chy Chien , Members, Doctoral Dissertation Committee Dr. Elizabeth K. Mann , Dr. Qiang Guan , Dr. Samuel Sprunt , Accepted by Dr. Antal Jákli , Chair, Chemical Physics Interdisciplinary program Dr. Mandy Munro-Stasiuk , Interim Dean, College of Arts and Sciences TABLE OF CONTENTS LIST OF FIGURES .................................................................................................................... IX LIST OF TABLES ..................................................................................................................... XX DEDICATION.......................................................................................................................... XXI ACKNOWLEDGEMENTS .................................................................................................. XXII CHAPTER 1 OVERVIEW .......................................................................................................... 1 1.1 Background ............................................................................................................................... 1 1.2 Overview of my work ............................................................................................................... 2 1.3 References ................................................................................................................................. 5 CHAPTER 2 NUMERICAL SIMULATION METHODS ..................................................... 10 2.1 Introduction ............................................................................................................................. 10 2.2 Current state and our goal ....................................................................................................... 10 2.3 Berreman method and FDTD method fundamental physics and equations ........................... 11 2.4 Modification of the simulation tools ....................................................................................... 12 2.5 Discussion and conclusion ...................................................................................................... 18 2.6 References ............................................................................................................................... 19 CHAPTER 3 NUMERICAL SIMULATION OF THE TRANSMISSIVE POLARIZATION VOLUME HOLOGRAMS ......................................................................................................... 20 3.1 Introduction ............................................................................................................................. 20 3.2 Current statement of liquid crystal transmissive polarization devices.................................... 21 3.2.1 Pancharatnam-Berry phase device ................................................................................... 21 III 3.2.2 Polarization gratings ......................................................................................................... 22 3.3 Simulation configurations and methods.................................................................................. 24 3.3.1 Basic director configurations of T-PVH gratings ............................................................ 25 3.3.2 Grating equations to define LC directors of each geometry ............................................ 27 3.3.3 FDTD method .................................................................................................................. 30 3.4 Simulation results.................................................................................................................... 31 3.4.1 Thickness impact of T-PVH ............................................................................................. 31 3.4.2 Small angle diffraction T-PVH comparison ..................................................................... 34 3.4.3 Large angle diffraction T-PVH comparison ..................................................................... 38 3.4.4 Slanted T-PVH ................................................................................................................. 41 3.5 T-PVH multiplexing by grating layers stack .......................................................................... 44 3.5.1 T-PVH multiplexing for broad wavelength bandwidth concept ...................................... 45 3.5.2 T-PVH multiplexing for broad angular bandwidth concept ............................................. 49 3.5.3. T-PVH multiplexing for broad wavelength and angular bandwidth ............................... 51 3.6 Discussion & Conclusions ...................................................................................................... 59 3.7 References ............................................................................................................................... 60 CHAPTER 4 THE TRANSMISSIVE POLARIZATION VOLUME HOLOGRAMS FABRICATION AND CHARACTERIZATION .................................................................... 65 4.1 Introduction ............................................................................................................................. 65 4.2 Materials properties exploration ............................................................................................. 66 IV 4.2.1 Previous development of the material M1 ....................................................................... 66 4.2.2 M1 thick film fabrication ................................................................................................. 67 4.2.3 M1 thick film polymerization with birefringence ............................................................ 69 4.2.4 M1 thick film birefringence distribution .......................................................................... 71 4.3 Grating exposure and characterization .................................................................................... 75 4.4 Comparison of the simulation and experiments...................................................................... 80 4.5 Grating quality improvement .................................................................................................. 86 4.6 conclusion ............................................................................................................................... 89 4.7 references: ............................................................................................................................... 89 CHAPTER 5 POLARIZATION STATE MANAGEMENT IN WAVEGUIDE DISPLAY USING PVH COUPLERS .......................................................................................................... 91 5.1 Introduction ............................................................................................................................. 91 5.2 Total internal reflection phase shift induced polarization state change .................................. 92 5.3 Using compensator to keep light propagating in waveguide being circular polarized ........... 95 5.3.1 Compensator for the incident light in 2D plane ............................................................... 95 5.3.2 Compensator for the incident light in 3D space ............................................................... 98 5.4 Compensator design to convert light polarization between circular and linear state in waveguide display ....................................................................................................................... 102 5.4.1 Design and simulation method ....................................................................................... 103 5.4.2 Simulation results and discussion .................................................................................. 104 V 5.5 Conclusion. ........................................................................................................................... 113 5.6 References. ............................................................................................................................ 113 CHAPTER 6 FAST CHOLESTERIC LIGHT SHUTTER FOR IMAGE OCCLUSION 116 6.1 Background of image occlusion ............................................................................................ 116 6.2 Statement of liquid crystal polarization light shutter ............................................................ 118 6.3 High transmission cholesteric shutter fabrication and characterization method .................. 121 6.3.1 Dynamic relaxing process measurement ........................................................................ 122 6.3.2 Optics measurement ....................................................................................................... 123 6.4 High transmission cholesteric shutter turn off characterization and simulation ................... 125 6.4.1 High transmission cholesteric shutter turn off characterization ..................................... 125 6.4.2 Director relaxing simulation ..........................................................................................