Liquid crystals / Iam-Choon Khoo.

Format:

Book

Author/Creator:

Khoo, Iam-Choon.

Series:

Wiley series in pure and applied optics

Language:

English

Subjects (All):

Liquid crystals.

Physical Description:

xiv, 368 pages : illustrations ; 25 cm.

Edition:

Second edition.

Place of Publication:

Hoboken, N.J. : Wiley-Interscience, [2007]

Summary:

An excellent professional reference and superior upper-level student text, Liquid Crystals, Second Edition is a comprehensive treatment of all the basic principles underlying the unique physical, and optical properties of liquid crystals. Written by an internationally known pioneer in the nonlinear optics of liquid crystals, the book also provides a unique, in-depth discussion of the mechanisms and theoretical principles behind all major nonlinear optical phenomena occurring in liquid crystals.

Fully revised and updated with the latest developments, this Second Edition covers: Basic physics and optical properties of liquid crystals, Nematics, as well as other mesophases such as smectics, ferroelectrics, and cholesterics, Fundamentals of liquid crystals for electro-optics, and display and non-display related applications, Various theoretical and computational techniques used in describing optical propagation through liquid crystals and anisotropic materials, Nonlinear optics of liquid crystals, including updated literature reviews and fundamental discussions.

Structured to follow a natural sequence of instruction, from basic physics to the latest specialized optical, electro-optical, and nonlinear applications, Liquid Crystals is a textbook that grounds students in the fundamentals before introducing them to the most current discoveries in the field. Written in a clear, reader-friendly style, it features numerous figures, tables, and illustrations, including important and hard-to-find device and material parameters. Invaluable to students, researchers, and those working with liquid crystal applications in various industries. Liquid Crystals, Second Edition is the most comprehensive and up-to-date resource available.

Contents:

1.1 Molecular Structures and Chemical Compositions 1

1.1.1 Chemical Structures 1

1.2 Electronic Properties 3

1.2.1 Electronic Transitions and Ultraviolet Absorption 3

1.2.2 Visible and Infrared Absolution 4

1.3 Lyotropic, Polymeric, and Thermotropic Liquid Crystals 6

1.3.1 Lyotropic Liquid Crystals 6

1.3.2 Polymeric Liquid Crystals 6

1.3.3 Thermotropic Liquid Crystals: Nematics, Cholesterics, and Smectics 7

1.3.4 Other Liquid Crystalline Phases and Molecular Engineered Structures 10

1.4 Mixtures and Composites 11

1.4.1 Mixtures 12

1.4.2 Dye-Doped Liquid Crystals 13

1.4.3 Polymer-Dispersed Liquid Crystals 14

1.5 Liquid Crystal Cells and Sample Preparation 14

1.5.1 Bulk Thin Film 15

1.5.2 Liquid Crystal Optical Slab Waveguide, Fiber, and Nanostructured Photonic Crystals 17

Chapter 2 Order Parameter, Phase Transition, and Free Energies 22

2.1.2 Scalar and Tensor Order Parameters 23

2.1.3 Long- and Short-Range Order 25

2.2 Molecular Interactions and Phase Transitions 26

2.3 Molecular Theories and Results for the Liquid Crystalline Phase 26

2.3.1 Maier-Saupe Theory: Order Parameter Near T[subscript c] 27

2.3.2 Nonequilibrium and Dynamical Dependence of the Order Parameter 29

2.4 Isotropic Phase of Liquid Crystals 32

2.4.1 Free Energy and Phase Transition 32

2.4.2 Free Energy in the Presence of an Applied Field 33

Chapter 3 Nematic Liquid Crystals 36

3.2 Elastic Continuum Theory 36

3.2.1 The Vector Field: Direct Axis n (r) 36

3.2.2 Elastic Constants, Free Energies, and Molecular Fields 38

3.3 Dielectric Constants and Refractive Indices 41

3.3.1 dc and Low-Frequency Dielectric Permittivity, Conductivities, and Magnetic Susceptibility 41

3.3.2 Free Energy and Torques by Electric and Magnetic Fields 44

3.4 Optical Dielectric Constants and Refractive Indices 45

3.4.1 Linear Susceptibility and Local Field Effect 45

3.4.2 Equilibrium Temperature and Order Parameter Dependences of Refractive Indices 47

3.5 Flows and Hydrodynamics 51

3.5.1 Hydrodynamics of Ordinary Isotropic Fluids 52

3.5.2 General Stress Tensor for Nematic Liquid Crystals 55

3.5.3 Flows with Fixed Director Axis Orientation 55

3.5.4 Flows with Director Axis Reorientation 57

3.6 Field-Induced Director Axis Reorientation Effects 58

3.6.1 Field-Induced Reorientation without Flow Coupling: Freedericksz Transition 58

3.6.2 Reorientation with Flow Coupling 61

Chapter 4 Cholesteric, Smectic, and Ferroelectric Liquid Crystals 64

4.1 Cholesteric Liquid Crystals 64

4.1.1 Free Energies 64

4.1.2 Field-Induced Effects and Dynamics 66

4.1.3 Twist and Conic Mode Relaxation Times 69

4.2 Light Scattering in Cholesterics 70

4.2.1 General Optical Propagation and Reflection: Normal Incidence 70

4.2.2 Cholesteric Liquid Crystal as a One-Dimensional Photonic Crystal 74

4.2.3 Cholesteric Liquid Crystals with Magneto-Optic Activity: Negative Refraction Effect 78

4.3 Smectic and Ferroelectric Liquid Crystals: A Quick Survey 80

4.4 Smectic-A Liquid Crystals 82

4.4.1 Free Energy 82

4.4.2 Light Scattering in SmA Liquid Crystals 84

4.5 Smectic-C Liquid Crystals 86

4.5.1 Free Energy 86

4.5.2 Field-Induced Director Axis Rotation in SmC Liquid Crystals 87

4.6 Smectic-C* and Ferroelectric Liquid Crystals 88

4.6.1 Free Energy of Ferroelectric Liquid Crystals 89

4.6.2 Smectic-C*-Smectic-A Phase Transition 93

Chapter 5 Light Scatterings 97

5.2 General Electromagnetic Formalism of Light Scattering in Liquid Crystals 98

5.3 Scattering from Director Axis Fluctuations in Nematic Liquid Crystals 100

5.4 Light Scattering in the Isotropic Phase of Liquid Crystals 104

5.5 Temperature, Wavelength, and Cell Geometry Effects on Scattering 107

5.6 Spectrum of Light and Orientation Fluctuation Dynamics 109

5.7 Raman Scatterings 111

5.7.2 Quantum Theory of Raman Scattering: Scattering Cross Section 112

5.8 Brillouin and Rayleigh Scatterings 115

5.8.1 Brillouin Scattering 117

5.8.2 Rayleigh Scattering 119

5.9 Nonlinear Light Scattering: Supraoptical Nonlinearity of Liquid Crystals 120

Chapter 6 Liquid Crystal Optics and Electro-Optics 124

6.2 Review of Electro-Optics of Anisotropic and Birefringent Crystals 125

6.2.1 Anisotropic, Uniaxial, and Biaxial Optical Crystals 125

6.2.2 Index Ellipsoid in the Presence of an Electric Field: Linear Electro-Optics Effect 127

6.2.3 Polarizers and Retardation Plate 128

6.2.4 Basic Electro-Optics Modulation 130

6.3 Electro-Optics of Nematic Liquid Crystals 131

6.3.1 Director Axis Reorientation in Homeotropic and Planar Cells: Dual-Frequency Liquid Crystals 131

6.3.2 Freedericksz Transition Revisited 133

6.3.3 Field-Induced Refractive Index Change and Phase Shift 136

6.4 Nematic Liquid Crystal Switches and Displays 138

6.4.1 Liquid Crystal Switch: On-Axis Consideration for Twist, Planar, and Homeotropic Aligned Cells 139

6.4.2 Off-Axis Transmission, Viewing Angle, and Birefringence Compensation 139

6.4.3 Liquid Crystal Display Electronics 141

6.5 Electro-Optical Effects in Other Phases of Liquid Crystals 142

6.5.1 Surface Stabilized FLC 142

6.5.2 Soft-Mode FLCs 144

6.6 Nondisplay Applications of Liquid Crystals 146

6.6.1 Liquid Crystal Spatial Light Modulator 146

6.6.2 Tunable Photonic Crystals with Liquid Crystal Infiltrated Nanostructures 148

6.6.3 Tunable Frequency Selective Planar Structures 148

6.6.4 Liquid Crystals for Molecular Sensing and Detection 150

6.6.5 Beam Steering, Routing, and Optical Switching and Laser Hardened Optics 152

Chapter 7 Electromagnetic Formalisms for Optical Propagation 157

7.2 Electromagnetism of Anisotropic Media Revisited 158

7.2.1 Maxwell Equations and Wave Equations 158

7.2.2 Complex Refractive Index 159

7.2.3 Negative Index Material 160

7.2.4 Normal Modes, Power Flow, and Propagation Vectors in a Lossless Isotropic Medium 163

7.2.5 Normal Modes and Propagation Vectors in a Lossless Anisotropic Medium 164

7.3 General Formalisms for Polarized Light Propagation Through Liquid Crystal Devices 168

7.3.1 Plane-Polarized Wave and Jones Vectors 169

7.3.2 Jones Matrix Method for Propagation Through a Nematic Liquid Crystal Cell 173

7.3.3 Oblique Incidence: 4X4 Matrix Methods 175

7.4 Extended Jones Matrix Method 177

7.5 Finite-Difference Time-Domain Technique 181

7.5.1 The Implementation of FDTD Methods 181

7.5.2 Example: FDTD Computations of the Twisted Nematic Cell in One Dimension 186

Chapter 8 Laser-Induced Orientational Optical Nonlinearities in Liquid Crystals 190

8.1 General Overview of Liquid Crystal Nonlinearities 190

8.2 Laser-Induced Molecular Reorientations in the Isotropic Phase 193

8.2.1 Individual Molecular Reorientations in Anisotropic Liquids 193

8.2.2 Correlated Molecular Reorientation Dynamics 196

8.2.3 Influence of Molecular Structure on Isotropic Phase Reorientational Nonlinearities 198

8.3 Molecular Reorientations in the Nematic Phase 200

8.3.1 Simplified Treatment of Optical Field-Induced Director Axis Reorientation 201

8.3.2 More Exact Treatment of Optical Field-Induced Director Axis Reorientation 204

8.3.3 Nonlocal Effect and Transverse Dependence 205

8.4 Nematic Phase Reorientation Dynamics 206

8.4.1 Plane Wave Optical Field 206

8.4.2 Sinusoidal Optical Intensity 210

8.5 Laser-Induced Dopant-Assisted Molecular Reorientation and Trans-Cis Isomerism 211

8.6 DC Field Aided Optically Induced Nonlinear Optical Effects in Liquid Crystals: Photorefractivity 213

8.6.1 Orientational Photorefractivity: Bulk Effects 215

8.6.2 Some Experimental Results and Surface Charge/Field Contribution 220

8.7 Reorientation and Nonelectronic Nonlinear Optical Effects in Smectic and Cholesteric Phases 221

8.7.1 Smectic Phase 221

8.7.2 Cholesteric Phase 222

Chapter 9 Thermal, Density, and Other Nonelectronic Nonlinear Mechanisms 227

9.2 Density and Temperature Changes

Induced by Sinusoidal Optical Intensity 230

9.3 Refractive Index Changes: Temperature and Density Effects 233

9.4 Thermal and Density Optical Nonlinearities of Nematic Liquid Crystals in the Visible-Infrared Spectrum 238

9.4.1 Steady-State Thermal Nonlinearity of Nematic Liquid Crystals 240

9.4.2 Short Laser Pulse Induced Thermal Index Change in Nematics and Near-T[subscript c] Effect 241

9.5 Thermal and Density Optical Nonlinearities of Isotropic Liquid Crystals 243

9.6 Coupled Nonlinear Optical Effects in Nematic Liquid Crystals 245

9.6.1 Thermal-Orientational Coupling in Nematic Liquid Crystals 246

9.6.2 Flow-Orientational Effect 247

Chapter 10 Electronic Optical Nonlinearities 253

10.2 Density Matrix Formalism for Optically Induced Molecular Electronic Polarizabilities 253

10.2.1 Induced Polarizations 256

10.2.2 Multiphoton Absoiptions 256

10.3 Electronic Susceptibilities of Liquid Crystals 259

10.3.1 Linear Optical Polarizabilities of a Molecule with No Permanent Dipole 259

10.3.2 Second-Order Electronic Polarizabilities 262

10.3.3 Third-Order Electronic Polarizabilities 264

10.4 Electronic Nonlinear Polarizations of Liquid Crystals 266

10.4.1 Local Field Effects and Symmetry 267

10.4.2 Symmetry Considerations 268

10.4.3 Permanent Dipole and Molecular Ordering 268

10.4.4 Quadrupole Contribution and Field-Induced Symmetry Breaking 269

10.4.5 Molecular Structural Dependence of Nonlinear Susceptibilities 269

11.1 Nonlinear Susceptibility and Intensity-Dependent Refractive Index 273

11.1.1 Nonlinear Polarization and Refractive Index 273

11.1.2 Nonlinear Coefficient and Units 276

11.2 General Nonlinear Polarization and Susceptibility 277

11.3 Convention and Symmetry 278

11.4 Coupled Maxwell Wave Equations 282

11.5 Nonlinear Optical Phenomena 284

11.5.1 Stationary Degenerate Four-Wave Mixing 284

11.5.2 Optical Phase Conjugation 288

11.5.3 Nearly Degenerate and Transient Wave Mixing 291

11.5.4 Nondegenerate Optical Wave Mixing: Harmonic Generations 294

11.5.5 Self-Focusing and Self-Phase Modulation 297

11.6 Stimulated Scatterings 303

11.6.1 Stimulated Raman Scatterings 303

11.6.2 Stimulated Brillouin Scatterings 306

11.6.3 Stimulated Orientational Scattering in Liquid Crystals 311

11.6.4 Stimulated Thermal Scattering (STS) 316

Chapter 12 Nonlinear Optical Phenomena Observed in Liquid Crystals 319

12.1 Self-Focusing, Self-Phase Modulation, and Self-Guiding 319

12.1.1 Self-Focusing and Self-Phase Modulation and Optical Limiting with Nematic Liquid Crystals 319

12.1.2 Self-Guiding, Spatial Soliton, and Pattern Formation 324

12.2 Optical Wave Mixing 326

12.2.1 Stimulated Orientational Scattering and Polarization Self-Switching: Steady State 326

12.2.2 Stimulated Orientational Scattering: Nonlinear Dynamics 329

12.2.3 Optical Phase Conjugation with Orientation and Thermal Gratings 332

12.2.4 Self-Starting Optical Phase Conjugation 333

12.3 Liquid Crystals for All-Optical Image Processing 337

12.3.1 Liquid Crystals as All-Optical Information Processing Materials 337

12.3.2 All-Optical Image Processing 339

12.3.3 Intelligent Optical Processing 341

12.4 Harmonic Generations and Sum-Frequency Spectroscopy 343

12.5 Optical Switching 344

12.6 Nonlinear Absorption and Optical Limiting of Short Laser Pulses in Isotropic Phase Liquid Crystals and Liquids 348

12.6.2 Nonlinear Fiber Array 350

12.6.3 RSA Materials (C60 Doped ILC) 351

12.6.4 Optical Limiting by TPA Materials (L34 Fiber Core Liquid) 355.

Notes:

Includes bibliographical references and index.

ISBN:

0471751537

9780471751533

OCLC:

69734668