Optical to Terahertz Engineering

This book highlights advances in the field of THz engineering along with limitations of radio frequency (RF) technology. All engineering applications have been designed to operate over a specific frequency or wavelength range in electromagnetic spectrum. In recent years, the unexplored domain of THz range of electromagnetic spectrum has paved the way for terahertz technology due to its nonionizing nature and sensitivity to water content. A wide range of applications with THz techniques such as terahertz time-domain spectroscopy (THz-TDS), biological, medical and pharmaceutical sciences, explosives inspection, information and communication technology (ICT) sector and many more, have potential to be the technology of future. Different designing aspects and evolving application areas are addressed to enrich the technical knowledge of readers. This book provides an overview of state of the art in terms of research and industrial progress in THz spectrum. Preface 6 Contents 8 About the Editors 10 Introduction to Terahertz Imaging Applications 14 1 Introduction 14 2 Instrumentation 15 2.1 Sources 15 2.2 Detectors 16 2.3 Optics 16 2.4 Signal Acquisition and Important Parameters 17 2.5 Signal Processing 17 3 Imaging 18 3.1 Imaging with Continuous-Wave (CW) THz Waves 18 3.2 Imaging with THz Pulses 19 3.3 Comparison 20 4 THz Tomography 21 5 Latest Developments 22 6 Conclusion 23 References 23 Design of Super-Achromatic Phase Controlling Assemblies for THz Spectro-Polarimetric Imaging System Using Metaheuristic Optimization Technique 29 1 Introduction 29 2 Theoretical Analysis 31 2.1 Designing Steps 31 3 Simulation Results and Discussion 33 4 Applications 36 5 Conclusion 37 References 38 On the Photoemission from Quantum Confined Heavily Doped THz Materials 41 1 Introduction 41 2 Method 42 3 Results and Discussions 42 4 Conclusion 44 References 55 Evolution of 6G and Terahertz Communication 57 1 Introduction 57 2 Background 57 3 Significance of Terahertz Frequency Bands 58 4 Challenging Issues in Terahertz Frequency Bands 59 5 Previous Works 59 6 Propagation Characteristics 60 7 Technologies Related to Channel, Antenna and Access Techniques 61 7.1 Channel Measurement Methods [60] 61 7.2 Channel Modelling Methods [61] 61 7.3 Multicarrier Techniques [62] 61 7.4 Channel Coding and Decoding [10] 61 7.5 Massive MIMO Systems [63–67] 61 7.6 OAM-Based Systems [68] 63 7.7 Non-orthogonal Multiple Access (NOMA) [69, 70] 63 8 Some Experimental Results and Discussions 64 9 Conclusions 67 References 67 Some Aspects of Novel Materials from Optical to THz Engineering 71 1 Introduction 71 2 Wide Bandgap Materials 73 2.1 Silicon Carbide (SiC) 73 2.2 Gallium Nitride (GaN) 74 2.3 Zn-Based Materials 75 3 Novel Material 79 3.1 Graphene Channel Photodetectors 79 3.2 Layered MoS2 Photo-Detector for Harsh Environment 81 3.3 Monolayer Nano Nets 82 3.4 Bi2S3 Nano-Belts 83 3.5 NiCo2O4 Nano-Film 85 4 Perovskite Materials 87 References 88 Optical Polarization Phase Modulation with Lithium Niobate 93 1 Introduction 93 2 Tunable Differential Optical Polarization Phase Realization with LN Crystal 94 2.1 Analysis of Electric Field by Schwarz-Christoffel Mapping or SCM Technique 95 2.2 Device Configuration with Non-parallel or Inclined Electrode Pair 100 2.3 Distribution of Electric Field Inside the Device 104 2.4 Optimization of Various Device Parameters 105 2.5 Introduction of Variable Phases 107 2.6 Tunability of the Device 108 3 Conclusion 109 References 110 Application of Fiber Optics for the Protection and Control of Power Systems 113 1 Introduction 113 2 Optical Fiber System 116 2.1 Construction of Optical Fiber 116 2.2 OFC Operating Principal 117 2.3 Classifications of Optical Fibers 118 2.4 Advantages of Fiber Optics 119 2.5 Disadvantages of OFC 119 2.6 Fiber Optic Communication 119 3 Electrical Power System Protection and Control System 125 3.1 Power System Protection 125 3.2 Qualities Required of a Protection System 128 4 Automation Power System Protection System with Fiber Optics 128 5 Conclusions 131 References 131 Orbital Angular Momentum of Light in Helically Twisted Hollow Core Photonic Crystal Fiber 133 1 Introduction 133 2 Dirac Like Bloch Modes in HC-PCF 135 3 DR in Helically Twisted HC-PCF 138 4 OAM Modes in Twisted HC-PCF 143 5 Dependency on Geometrical Parameters 150 5.1 Core Geometry 150 5.2 PC Size 151 6 Conclusion 152 References 152 Review of Various Codes and Transmitter–Receiver Architecture Used in Optical Code Multiple Access System 154 1 Introduction 154 1.1 Bipolar OCDMA Code 155 1.2 Unipolar OCDMA Codes 157 1.3 Weighted Position Representation (WPR) of Unipolar OCDMA Code (1-D) 165 1.4 Correlation Constraints of Unipolar Optical Codes 166 1.5 Review of Different Transmitter Receiver Architectures of the OCDMA System 167 2 Conclusion 172 References 172 Error Detection and Correction of High-Resolution Remote Sensing Images Using Cyclic Code 174 1 Introduction 174 2 Methodology 175 3 Flow Chart 177 4 Result and Analysis 177 5 Advantage 181 6 Limitation 181 7 Conclusion 181 References 182 Segmentation of Used Biodegradable and Non-biodegradable Products of Covid 19 Patients Using Thermal Image Processing 184 1 Introduction 184 2 Biodegradable and Non-biodegradable Materials 186 2.1 Biodegradable 186 2.2 Non-biodegradable 186 3 Long Term Effect of Waste Materials on the Environment 187 4 Methodology 187 5 Result 189 6 Analysis 189 7 Comparison with Existing Methods 191 8 Conclusion 191 References 191