Active Terahertz Metamaterial for Biomedical Applications

Active Terahertz Metamaterial for Biomedical Applications PDF Author: Balamati Choudhury
Publisher: Springer
ISBN: 9812877932
Category : Technology & Engineering
Languages : en
Pages : 63

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Book Description
This book describes a metamaterial-based active absorber for potential biomedical engineering applications. Terahertz (THz) spectroscopy is an important tool for imaging in the field of biomedical engineering, due to the non-invasive, non-ionizing nature of terahertz radiation coupled with its propagation characteristics in water, which allows the operator to obtain high-contrast images of skin cancers, burns, etc. without detrimental effects. In order to tap this huge potential, it is important to build highly efficient biomedical imaging systems by introducing terahertz absorbers into biomedical detectors. The biggest challenge faced in the fulfilment of this objective is the lack of naturally occurring dielectrics, which is overcome with the use of artificially engineered resonant materials, viz. metamaterials. This book describes such a metamaterial-based active absorber. The design has been optimized using particle swarm optimization (PSO), eventually resulting in an ultra-thin active terahertz absorber. The absorber shows near unity absorption for a tuning range of terahertz (THz) application.

Active Terahertz Metamaterial for Biomedical Applications

Active Terahertz Metamaterial for Biomedical Applications PDF Author: Balamati Choudhury
Publisher: Springer
ISBN: 9812877932
Category : Technology & Engineering
Languages : en
Pages : 63

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Book Description
This book describes a metamaterial-based active absorber for potential biomedical engineering applications. Terahertz (THz) spectroscopy is an important tool for imaging in the field of biomedical engineering, due to the non-invasive, non-ionizing nature of terahertz radiation coupled with its propagation characteristics in water, which allows the operator to obtain high-contrast images of skin cancers, burns, etc. without detrimental effects. In order to tap this huge potential, it is important to build highly efficient biomedical imaging systems by introducing terahertz absorbers into biomedical detectors. The biggest challenge faced in the fulfilment of this objective is the lack of naturally occurring dielectrics, which is overcome with the use of artificially engineered resonant materials, viz. metamaterials. This book describes such a metamaterial-based active absorber. The design has been optimized using particle swarm optimization (PSO), eventually resulting in an ultra-thin active terahertz absorber. The absorber shows near unity absorption for a tuning range of terahertz (THz) application.

Active Terahertz Metamaterials

Active Terahertz Metamaterials PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description


Active Metamaterials

Active Metamaterials PDF Author: Saroj Rout
Publisher: Springer
ISBN: 3319522191
Category : Technology & Engineering
Languages : en
Pages : 126

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Book Description
This book covers the theoretical background, experimental methods and implementation details to engineer for communication and imaging application, terahertz devices using metamaterials, in mainstream semiconductor foundry processes. This book will provide engineers and physicists an authoritative reference to construct such devices with minimal background. The authors describe the design and construction of electromagnetic (EM) devices for terahertz frequencies (108-1010 cycles/sec) using artificial materials that are a fraction of the wavelength of the incident EM wave, resulting in an effective electric and magnetic properties (permittivity and permeability) that are unavailable in natural materials.

Active Terahertz Metamaterial Devices

Active Terahertz Metamaterial Devices PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
Metamaterial structures are taught which provide for the modulation of terahertz frequency signals. Each element within an array of metamaterial (MM) elements comprises multiple loops and at least one gap. The MM elements may comprise resonators with conductive loops and insulated gaps, or the inverse in which insulated loops are present with conductive gaps; each providing useful transmissive control properties. The metamaterial elements are fabricated on a semiconducting substrate configured with a means of enhancing or depleting electrons from near the gaps of the MM elements. An on to off transmissivity ratio of about 0.5 is achieved with this approach. Embodiments are described in which the MM elements incorporated within a Quantum Cascade Laser (QCL) to provide surface emitting (SE) properties.

Frequency Selective Surfaces

Frequency Selective Surfaces PDF Author: Ben A. Munk
Publisher: John Wiley & Sons
ISBN: 0471723762
Category : Technology & Engineering
Languages : en
Pages : 442

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Book Description
"...Ben has been the world-wide guru of this technology, providing support to applications of all types. His genius lies in handling the extremely complex mathematics, while at the same time seeing the practical matters involved in applying the results. As this book clearly shows, Ben is able to relate to novices interested in using frequency selective surfaces and to explain technical details in an understandable way, liberally spiced with his special brand of humor... Ben Munk has written a book that represents the epitome of practical understanding of Frequency Selective Surfaces. He deserves all honors that might befall him for this achievement." -William F. Bahret. Mr. W. Bahret was with the United States Air Force but is now retired. From the early 50s he sponsored numerous projects concerning Radar Cross Section of airborne platforms in particular antennas and absorbers. Under his leadership grew many of the concepts used extensively today, as for example the metallic radome. In fact, he is by many considered to be the father of stealth technology. "This book compiles under one cover most of Munk's research over the past three decades. It is woven with the physical insight that he has gained and further developed as his career has grown. Ben uses mathematics to whatever extent is needed, and only as needed. This material is written so that it should be useful to engineers with a background in electromagnetics. I strongly recommend this book to any engineer with any interest in phased arrays and/or frequency selective surfaces. The physical insight that may be gained from this book will enhance their ability to treat additional array problems of their own." -Leon Peters, Jr. Professor Leon Peters, Jr., was a professor at the Ohio State University but is now retired. From the early sixties he worked on, among many other things, RCS problems involving antennas and absorbers. This book presents the complete derivation of the Periodic Method of Moments, which enables the reader to calculate quickly and efficiently the transmission and reflection properties of multi-layered Frequency Selective Surfaces comprised of either wire and/or slot elements of arbitrary shape and located in a stratified medium. However, it also gives the reader the tools to analyze multi-layered FSS's leading to specific designs of the very important Hybrid Radome, which is characterized by constant band width with angle of incidence and polarization. Further, it investigates in great detail bandstop filters with large as well as narrow bandwidth (dichroic surfaces). It also discusses for the first time, lossy elements used in producing Circuit Analog absorbers. Finally, the last chapter deals with power breakdown of FSS's when exposed to pulsed signals with high peak power. The approach followed by most other presentations simply consists of expanding the fields around the FSS, matching the boundary conditions and writing a computer program. While this enables the user to obtain calculated results, it gives very little physical insight and no help in how to design actual multi-layered FSS's. In contrast, the approach used in this title analyzes all curves of desired shapes. In particular, it discusses in great detail how to produce radomes made of FSS's located in a stratified medium (Hybrid Radomes), with constant band width for all angles of incidence and polarizations. Numerous examples are given of great practical interest. More specifically, Chapter 7 deals with the theory and design of bandpass radomes with constant bandwidth and flat tops. Examples are given for mono-, bi- and tri-planar designs. Chapter 8 deals with bandstop filters with broad as well as narrow bandwidth. Chapter 9 deals with multi-layered FSS of lossy elements, namely the so-called Circuit Analog Absorbers, designed to yield outstanding absorption with more than a decade of bandwidth. Features material previously labeled as classified by the United States Air Force.

Handbook of Terahertz Technologies

Handbook of Terahertz Technologies PDF Author: Ho-Jin Song
Publisher: CRC Press
ISBN: 9814613096
Category : Science
Languages : en
Pages : 606

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Book Description
Terahertz waves, which lie in the frequency range of 0.1-10 THz, have long been investigated in a few limited fields, such as astronomy, because of a lack of devices for their generation and detection. Several technical breakthroughs made over the last couple of decades now allow us to radiate and detect terahertz waves more easily, which has trigg

Terahertz Quantum-cascade Transmission-line Metamaterials

Terahertz Quantum-cascade Transmission-line Metamaterials PDF Author: Amir Ali Tavallaee
Publisher:
ISBN:
Category :
Languages : en
Pages : 146

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Book Description
Terahertz quantum-cascade (QC) lasers operating at 0.6 − 5 THz (λ ∼ 60 − 500 μm) are poised to become the dominant solid-state sources of continuous-wave (cw) far-infrared radiation enabling applications in terahertz spectroscopy, imaging, and sensing. QC-lasers are the longest wavelength semiconductor laser sources in which terahertz gain is obtained from electronic intersubband radiative transitions in GaAs/AlGaAs heterostructure quantum wells. Since their invention in 2001, rapid development has enabled demonstration of cw powers greater than 100 mW. However, challenges still remain in the areas of operating temperature, laser efficiency and power, and beam quality to name a few. The highest-temperature operation of terahertz quantum-cascade lasers (200 K pulsed, 117 K cw) depends on the use of a low-loss "metal-metal" waveguide where the active gain material is sandwiched between two metal cladding layers; a technique similar, in concept, to microstrip transmission line technology at microwave frequencies. Due to the subwavelength transverse dimensions of the metal-metal waveguide, however, obtaining a directive beam pattern and efficient out-coupling of THz power is non-trivial. This thesis reports the demonstration of a one-dimensional waveguide for terahertz quantum-cascade lasers that acts as a leaky-wave antenna and tailors laser radiation in one dimension to a directional beam. This scheme adapts microwave transmission-line metamaterial concepts to a planar structure realized in terahertz metal-metal waveguide technology and is fundamentally different from distributed feedback/photonic crystal structures that work based on Bragg scattering of propagating modes. The leaky-wave metamaterial antenna operates based on a propagating mode with an effective phase index smaller than unity such that it radiates in the surface direction via a leaky-wave mechanism. Surface emission (∼ 40◦ from broadside) with a single directive beam (FWHM ∼ 15◦) at 2.74 THz was demonstrated from terahertz QC-lasers with leaky-wave coupler antennas which exhibited slope efficiencies ∼ 4 times greater than conventional Fabry-Perot metal-metal waveguides. Using this technique the first demonstration of beam scanning for a terahertz QC-laser was reported (from 35◦ − 60◦) as the emission frequency varied from 2.65 − 2.81 THz. Towards the bigger goal of realizing an active terahertz metamaterial to ultimately develop "zero-index" terahertz quantum-cascade lasers immune to spatial hole burning, or "negative-index" metamaterials for superresolution terahertz imaging, a composite right-/left-handed transmission-line metamaterial based upon subwavelength metal waveguide loaded with terahertz QC material was demonstrated. Due to the addition of distributed series capacitors (realized by introducing gaps in top metallization) and shunt inductors (realized by operating in the higher-order lateral mode of the waveguide), the transmission-line metamaterial exhibits left-handed (backward waves or negative index) leaky-wave propagation from 2.3 − 2.45 THz in addition to the conventional right-handed leaky-wave behavior (from 2.6 − 3.0 THz).

Terahertz Technology

Terahertz Technology PDF Author: Borwen You
Publisher: BoD – Books on Demand
ISBN: 1839626127
Category : Science
Languages : en
Pages : 219

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Book Description
Electromagnetic waves within a terahertz frequency range are becoming critical to investigating molecules, materials, and possible applications that are operated by both visible light and infrared rays. This book discusses sensing, imaging, and optoelectronic technologies of terahertz electromagnetic waves in theory and experiments. Most terahertz technologies can be explained by fundamentals of applied physics that have been demonstrated in other spectral ranges. However, the optoelectronic technology and corresponding configurations of imaging and sensing techniques are so special for various terahertz material polarization waves, which are excited in solid-state media by high-peak power lasers and waveguide transportation. Thus, this book also specifies terahertz parameters and available technologies.

Metamaterials for Perfect Absorption

Metamaterials for Perfect Absorption PDF Author: Young Pak Lee
Publisher: Springer
ISBN: 9811001057
Category : Science
Languages : en
Pages : 180

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Book Description
This book provides a comprehensive overview of the theory and practical development of metamaterial-based perfect absorbers (MMPAs). It begins with a brief history of MMPAs which reviews the various theoretical and experimental milestones in their development. The theoretical background and fundamental working principles of MMPAs are then discussed, providing the necessary background on how MMPAs work and are constructed. There then follows a section describing how different MMPAs are designed and built according to the operating frequency of the electromagnetic wave, and how their behavior is changed. Methods of fabricating and characterizing MMPAs are then presented. The book elaborates on the performance and characteristics of MMPAs, including electromagnetically-induced transparency (EIT). It also covers recent advances in MMPAs and their applications, including multi-band, broadband, tunability, polarization independence and incidence independence. Suitable for graduate students in optical sciences and electronic engineering, it will also serve as a valuable reference for active researchers in these fields.

Dielectric Metamaterials

Dielectric Metamaterials PDF Author: Igal Brener
Publisher: Woodhead Publishing
ISBN: 0081024037
Category : Science
Languages : en
Pages : 310

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Book Description
Dielectric Metamaterials: Fundamentals, Designs and Applications links fundamental Mie scattering theory with the latest dielectric metamaterial research, providing a valuable reference for new and experienced researchers in the field. The book begins with a historical, evolving overview of Mie scattering theory. Next, the authors describe how to apply Mie theory to analytically solve the scattering of electromagnetic waves by subwavelength particles. Later chapters focus on Mie resonator-based metamaterials, starting with microwaves where particles are much smaller than the free space wavelengths. In addition, several chapters focus on wave-front engineering using dielectric metasurfaces and the nonlinear optical effects, spontaneous emission manipulation, active devices, and 3D effective media using dielectric metamaterials. Highlights a crucial link in fundamental Mie scattering theory with the latest dielectric metamaterial research spanning materials, design and applications Includes coverage of wave-front engineering and 3D metamaterials Provides computational codes for calculating and simulating Mie resonances