Preface	6
	Acknowledgments	8
	Contents	9
	1 Introduction	12
	1.1 Towards Closing the ``Terahertz Gap''	12
	1.1.1 Why Is the ``Terahertz Gap'' Interesting	14
	1.1.1.1 Continuous-Wave Terahertz System for Inspection Applications	15
	1.1.1.2 Giga-Bit Wireless Link Using 300–400GHz Bands	16
	1.1.2 A Brief History of Terahertz Technologies	17
	1.2 Introduction to Metamaterials	19
	1.2.1 A Brief History	19
	1.2.2 Overview of Metamaterials	20
	1.2.2.1 Magnetic Split-Ring Resonator (SRR)	22
	1.2.2.2 Electrically Coupled LC Resonator (ELC)	24
	1.2.3 Metamaterials: A Suitable Technology for Terahertz Devices	25
	1.2.3.1 Brief Overview of Metamaterial Based Terahertz Devices	26
	1.3 Overview of Terahertz Wave Modulators	27
	References	32
	2 Background Theory	37
	2.1 Plane Waves in a Nonconducting Medium	37
	2.1.1 Negative Refractive Index	40
	2.1.2 Propagation of Waves in Left-Handed Material	40
	2.1.3 Propagation of Waves in Single Negative Medium	41
	2.2 Dispersion in Nonconductors	41
	2.2.1 Lorentz Oscillator Model for Permitivity	42
	2.2.2 Anomalous Dispersion and Resonant Absorption	43
	2.3 Metamaterial as a Modulator	46
	References	48
	3 Experimental Methods	50
	3.1 Electromagnetic Modeling and Simulations of Metamaterials	50
	3.1.1 Boundary and Symmetry Conditions	51
	3.1.2 Homogenous Parameter Extraction	52
	3.2 Design for Fabrication in Foundry Processes	52
	3.2.1 Typical 45nm CMOS Process	53
	3.2.2 Physical Properties of Metal and Dielectrics at Optical Frequencies	54
	3.2.3 Case Studies	55
	3.2.3.1 Single Layer Metamaterial Operating at 100m Wavelength	56
	3.2.3.2 Multi-Layer Metamaterial Design	57
	3.3 Test and Characterization	59
	3.3.1 Terahertz Time-Domain Spectroscopy (THz-TDS)	59
	3.3.1.1 Terahertz Time-Domain Spectrometer	59
	3.3.1.2 Laser Sources	60
	3.3.1.3 THz Transmitters and Detectors	60
	3.3.1.4 Bandwidth Limitation of THz Detectors	61
	3.3.1.5 Collimating and Focusing Optics	62
	3.3.1.6 Lock-In Detection	63
	3.3.1.7 Terahertz Time-Domain Data Analysis	64
	3.3.2 Continuous-Wave (cw) Terahertz Spectroscopy	65
	3.3.2.1 A Continuous-Wave Terahertz (cw-THz) Spectrometer	65
	3.3.2.2 Laser Sources	66
	3.3.2.3 THz Transmitters and Detectors	67
	3.3.2.4 Data Analysis	68
	3.3.3 Optical Alignment of Off-Axis Parabolic Mirrors	69
	3.3.3.1 Alignment Procedure	70
	3.3.3.2 Vertical Alignment	71
	3.3.3.3 Horizontal Alignment	72
	References	73
	4 High-Speed Terahertz Modulation Using Active Metamaterial	76
	4.1 Introduction	76
	4.2 Design Principle of the HEMT Controlled MetamaterialModulator	77
	4.2.1 Circuit Model for the Electric-Coupled LC(ELC) Resonator	78
	4.2.2 Principle of Voltage Controlled Terahertz WaveModulator	80
	4.3 Design and Fabrication	82
	4.4 Experimental Setup	84
	4.5 Results and Discussion	86
	4.5.1 THz Transmission with DC-Biased HEMT	86
	4.5.2 Computational Investigation	87
	4.5.3 High Frequency THz Modulation	88
	References	90
	5 A Terahertz Spatial Light Modulator for Imaging Application	92
	5.1 Introduction to Single-Pixel Imaging	92
	5.1.1 A Brief Historical Perspective	94
	5.1.2 Imaging Theory	95
	5.2 A Review of THz Spatial Light Modulators	96
	5.3 Spatial Light Modulator Design and Assembly	99
	5.4 Circuit Design for Electronic Control of the SLM	104
	5.5 Experimental Setup for Terahertz Characterization and Imaging	105
	5.6 Results and Discussions	106
	5.6.1 Terahertz Characterization of the Spatial LightModulator	106
	5.6.2 Single-Pixel Terahertz Imaging	107
	References	109
	6 A Terahertz Focal Plane Array Using Metamaterials in a CMOS Process	111
	6.1 Introduction	111
	6.2 A 0.18?m CMOS Foundry Process Technology	112
	6.3 Principle of Resistive Self-Mixing Detection	114
	6.4 Metamaterial Based Terahertz CMOS Detector Design	116
	6.4.1 Terahertz Detection Using Source-Driven Self-Mixing Architecture	116
	6.4.2 Circuit Architecture for Terahertz Detection	117
	6.5 Metamaterial Design for Terahertz Detection	117
	6.6 Design of the Test Chip in 0.18?m CMOS Process	121
	6.7 Circuit Simulation Results	122
	References	123
	Appendix A Electromagnetic Waves	125
	A.1 Helmholtz's Equation	125
	A.2 Electromagnetic Waves Are Transverse	125