Active Metamaterials (eBook)

Dr. Saroj Rout received his Ph.D. in Electrical Engineering from Tufts University, Medford, Massachusetts, USA, where he worked on metamaterials for his doctoral dissertation.  He received his Masters and Bachelors in engineering from Birla Institute of Technology and Science (BITS), Pilani, India. He is a passionate teacher and has taught undergraduate electrical engineering courses at Tufts University and BITS, Pilani. He is an accomplished semiconductor professional with more than 18 years of experience in research and development of more than 10 semiconductor products in the area of communication and navigation. Two of the products have sold more than 1.5 billion units to date. He is the co-inventor of 7 patents in the area of CMOS VLSI design and metamaterials.He is the founder and principal engineer at Mixignal Innovations LLC, a VLSI circuit design consulting firm which provides turnkey solutions to semiconductor companies. He is also an adjunct professor at Silicon Institute of Technology, India, where he is developing a research center in the area of CMOS analog VLSI design.Prof. Sameer R Sonkusale is a Professor of Electrical Engineering with a joint appointment (courtesy) of Biomedical Engineering at Tufts University.  Prior to coming to Tufts, he was an Assistant Professor at Texas A&M University, College Station, Tx from 2002 to 2004. For the year 2011-2012, he was also a visiting associate professor of medicine at Harvard Medical School and Brigham and Womens Hospital. Prior to an academic career, he worked  for Texas Instruments  in Bangalore India from 1996-1997. Prof. Sonkusale received his MS and PhD in Electrical Engineering from University of Pennsylvania under the supervision of Prof. Jan Van der Spiegel  where he worked on pipeliend analog to digital converters for his doctoral dissertation.  He was co-advised by Dr. K. Nagaraj from Texas Instruments and by Prof. Ken Laker at University of Pennsylvania. His undergraduate degree is in Electrical and Electronics Engineering from Birla Institute of Technology and Science (BITS Pilani), India. Prof. Sonkusale's teaching and research interests are in the area of flexible bioelectronics, biomedical micro- and nanodevices, lab-on-chip systems, nanoscale sensors,  low power integrated circuits, analog to information converters, and active metamaterials for terahertz applications. His current research on "smart threads" to use engineered smart nano-infused threads for surgical sutures, wound dressings and wearable diagnsotics has been featured prominently by leading news organizations like the Wall Street Journal, Fortune Magazine, Fast Company, Inc.com, National Public Radio (WBUR), IEEE Spectrum, The Telegraph (UK) to name a few.Prof. Sonkusale is also passionate  about making low cost diagnostics for the developing world and believes  strongly in the democratization of science and innovation. He serves on the board of the Science for the Public, a non-profit organization to improve public understanding of, and appreciation for, science. Prof. Sonkusale received the NSF CAREER award in 2010, the Future Trends in Microelectronics Best poster prize in 2009, and has won several best paper awards with his students at many international conferences (NANO 2008, SENSORS 2008, ISDRS 2009, FTM 2009). He is a past fellow of NAE Frontiers of Engineering in 2015 and NAS Arab-US Frontiers in Science, Engineering and Medicine in 2014 and 2016.  Prof. Sonkusale is currently on the editorial board of Nature Scientific Reports, IEEE Transactions on Biomedical Circuits and Systems and IET Electronics Letters. He is a past associate editor of IEEE Transactions of Circuits and Systems-1 and a past chair of CAS Biomedical and Lifesciences Technical Commitee.  Prof. Sonkusale is a senior member of the IEEE, OSA, MRS and AAAS. 

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