A Small Footprint Digital Isolator based on CMOS Integrated Hall-effect Sensor

ABSTRACT: —Digital isolators have been widely used to protect low voltage electronics as well as human safety from high voltage surges. However, conventional isolation links occupy large chip areas. In this article, a novel small-size on-chip digital isolator for medium-bitrate application based on a CMOS integrated Hall-effect sensor is reported. With the proposed approach, the area of the transmitter coil is reduced to lower than 50% of conventional transformers. The architecture reduces the chip area in isolation amplifiers, power control units, DC-DC converters, and clock recovery circuits. It allows the integration of multichannel isolators using two custom integrated circuits with no post-processing. The tested prototype achieves a data transfer rate of 20 Mbps with above 12 kV/μs of common-mode transient immunity (CMTI). It has 900 V of continuous isolation working voltage, 27 ns propagation delay, and consumes 2.3 mA of static current

Recent Advances and Future Trends in Nanophotonics

Nanophotonics has emerged as a multidisciplinary frontier of science and engineering. Due to its high potential to contribute to breakthroughs in many areas of technology, nanophotonics is capturing the interest of many researchers from different fields. This Special Issue of Applied Sciences on “Recent advances and future trends in nanophotonics” aims to give an overview on the latest developments in nanophotonics and its roles in different application domains. Topics of discussion include, but are not limited to, the exploration of new directions of nanophotonic science and technology that enable technological breakthroughs in high-impact areas mainly regarding diffraction elements, detection, imaging, spectroscopy, optical communications, and computing

Functional optical surfaces by colloidal self-assembly: Colloid-to-film coupled cavities and colloidal lattices

Future developments in nanophotonics require facile, inexpensive and parallelizable fabrication methods and need a fundamental understanding of the spectroscopic properties of such nanostructures. These challenges can be met through colloidal self-assembly where pre-synthesized colloids are arranged over large areas at reasonable cost. As so-called colloidal building blocks, plasmonic nanoparticles and quantum dots are used because of their localized light confinement and localized light emission, respectively. These nanoscopic colloids acquires new hybrid spectroscopic properties through their structural arrangement. To explore the energy transfer between these nanoscopic building blocks, concepts from physical optics are used and implemented with the colloidal self-assembly approach from physical chemistry. Through an established synthesis, the nanocrystals are now available in large quantities, any they receive the tailored spectroscopic properties through directed self-assembly. Moreover, the tailored properties of the colloids and the use of stimuli-responsive polymers allow a functionality that goes beyond current developments. The basics developed in this habilitation thesis can lead to novel functional devices in the field of smart sensors, dynamic light modulators, and large-area quantum devices.:1 Abstract 2 2 State of the art 4 2.1 Metallic and semiconductive nanocrystals as colloidal building blocks 4 2.2 Concept of large-scale colloidal self-assembly 7 2.3 Functional optical nanomaterials by colloidal self-assembly 9 2.4 Scope 13 2.5 References 14 3 Single colloidal cavities 20 3.1 Nanorattles with tailored electric field enhancement 20 4 Colloidal -to-film coupled cavities 31 4.1 Template-assisted colloidal self-assembly of macroscopic magnetic metasurfaces 31 4.2 Single particle spectroscopy of radiative processes in colloid-to-film-coupled nanoantennas 50 4.3 Active plasmonic colloid-to-film coupled cavities for tailored light-matter interactions 65 5 Colloidal polymers 74 5.1 Direct observation of plasmon band formation and delocalization in quasi-infinite nanoparticle chains 74 6 Colloidal lattice 84 6.1 Hybridized guided-node resonances via colloidal plasmonic self-assembled grating 84 6.2 Mechanotunable surface lattice resonances in the visible optical range by soft lithography templates and directed self-assembly 94 6.3 Tunable Circular Dichroism by Photoluminescent Moiré Gratings 103 7 Conclusion and perspective 112 8 Appendix 113 8.1 Further publications during the habilitation period 113 8.2 Curriculum vitae of the author 116 9 Acknowledgments 117 10 Declaration 118Zukünftige Entwicklungen in der Nanophotonik erfordern einfache, kostengünstige und parallelisierbare Herstellungsmethoden und benötigen ein grundlegendes Verständnis der spektroskopischen Eigenschaften solcher Nanostrukturen. Diese Herausforderungen können durch kolloidale Selbstorganisation erfüllt werden, bei der kostengünstige und zuvor synthetisierte Kolloide großflächig angeordnet werden. Als sogenannte kolloide Bausteine werden wegen ihrer lokalisierten Lichtfokussierung unterhalb der Beugungsbegrenzung plasmonische Nanopartikel sowie wegen ihrer lokalisierten Lichtemission Quantenpunkte verwendet. Diese nanoskopischen Kolloide werden in dieser Habilitationsschrift verwendet und durch Selbstanordnung in ihre gewünschte Nanostruktur gebracht, die neue hybride Eigenschaften aufweist. Um den Energietransfer zwischen diesen nanoskopischen Bausteinen zu untersuchen, werden Konzepte aus der physikalischen Optik verwendet und mit dem kolloidalen Selbstorganisationskonzept aus der physikalischen Chemie großflächig umgesetzt. Durch eine etablierte Synthese sind die Nanokristalle nun in großen Mengen verfügbar, wobei sie durch gerichtete Selbstorganisation die gewünschten spektroskopischen Eigenschaften erhalten. Darüber hinaus ermöglicht die Verwendung von stimulierbaren Polymeren eine Funktionalität, die über die bisherigen Entwicklungen hinausgeht. Die in dieser Habilitationsschrift entwickelten Grundlagen können bei der Entwicklung neuartiger Funktionsgeräte im Bereich für intelligente Sensorik, dynamischer Lichtmodulatoren und großflächiger Quantengeräte genutzt werden.:1 Abstract 2 2 State of the art 4 2.1 Metallic and semiconductive nanocrystals as colloidal building blocks 4 2.2 Concept of large-scale colloidal self-assembly 7 2.3 Functional optical nanomaterials by colloidal self-assembly 9 2.4 Scope 13 2.5 References 14 3 Single colloidal cavities 20 3.1 Nanorattles with tailored electric field enhancement 20 4 Colloidal -to-film coupled cavities 31 4.1 Template-assisted colloidal self-assembly of macroscopic magnetic metasurfaces 31 4.2 Single particle spectroscopy of radiative processes in colloid-to-film-coupled nanoantennas 50 4.3 Active plasmonic colloid-to-film coupled cavities for tailored light-matter interactions 65 5 Colloidal polymers 74 5.1 Direct observation of plasmon band formation and delocalization in quasi-infinite nanoparticle chains 74 6 Colloidal lattice 84 6.1 Hybridized guided-node resonances via colloidal plasmonic self-assembled grating 84 6.2 Mechanotunable surface lattice resonances in the visible optical range by soft lithography templates and directed self-assembly 94 6.3 Tunable Circular Dichroism by Photoluminescent Moiré Gratings 103 7 Conclusion and perspective 112 8 Appendix 113 8.1 Further publications during the habilitation period 113 8.2 Curriculum vitae of the author 116 9 Acknowledgments 117 10 Declaration 11

Transmission of the Magnetic Field to Nanoscale and Investigation of Its Spintronic Effects.

PhD ThesesWhile we are gradually approaching the fundamental limit of integrated circuits in classic electronics, smaller devices and new carriers for the information and signals are still in demand. There is also a problem of designing energy efficient electronics. One of the common issues in this area is how to manipulate microwave at very small scales, i.e., nanometers. Currently the fabrication of nanostructured materials either physically or in composition, and of nanoscale objects such as nanoparticles, nanotubes and nanowires is performed routinely in many research laboratories and private companies. In addition, the physical properties of these structures and objects (mechanical, electrical, magnetic etc.) are also relatively well understood in the two extreme frequency ranges corresponding to the low frequency range (up to 100 MHz) and to the optical frequency range (above THz). However, for the microwave frequency range 1 GHz-100 GHz most of these properties at the nanoscale are still to be investigated. The main reason for this situation has been the lack of enough development of theoretical and experimental techniques and tools to investigate this interaction at the nanoscale. In this thesis, different approaches for characterization of nanostructures at microwave frequencies., namely, Atomic Force Microscope (AFM), the Electrostatic Force Microscope (EFM) and the Scanning Microwave Microscope (SMM) were performed. Before going deeply to the practice and simulation the basic principles of quantum mechanics were considered to understand the processes happening at the end of the tip, probe or any nanoscale source in free space. This theory is well-connected to the feeding device optimization study presented as it is shown Chapter 3 where the numerical simulation of the single electron wave function is shown. It has provided the first contribution of this thesis where the improvement of the AFM tip simulation is shown. The second objective of this thesis was to determine how the microwaves propagate, reflect or are transmitted from the nanoscale object. The optimization study results of the feeding device for a hall bar structure were presented in order to do that. The properties of this device were investigated theoretically and numerically. The optimized structure then will be prepared for the fabrication, i.e., the mask for electronbeam lightning will be presented

Advanced Gas Turbine (AGT) powertrain system

A 74.5 kW(100 hp) advanced automotive gas turbine engine is described. A design iteration to improve the weight and production cost associated with the original concept is discussed. Major rig tests included 15 hours of compressor testing to 80% design speed and the results are presented. Approximately 150 hours of cold flow testing showed duct loss to be less than the design goal. Combustor test results are presented for initial checkout tests. Turbine design and rig fabrication is discussed. From a materials study of six methods to fabricate rotors, two have been selected for further effort. A discussion of all six methods is given

Spintronic properties of carbon and silicon based nanostructures

Ankara : The Department of Physics and the Institute of Engineering and Science of Bilkent University, 2007.Thesis (Ph.D.) -- Bilkent University, 2007.Includes bibliographical references leaves 101-109.In this thesis, nanostructures which may display novel spintronic behaviors are revealed and their properties are investigated by using first-principles methods. We have concentrated on three different systems, namely carbon linear chains, singe-wall carbon nanotubes and silicon nanowires. First of all, an extensive study of the electronic, magnetic and transport properties of finite and infiniteperiodic atomic chains composed of carbon atoms and 3d transition metal (TM) atoms are carried out. Finite-size, linear molecules made of carbon atomic chains caped with TM atoms, i.e. TM-Cn-TM structures are found to be stable and exhibit interesting magnetoresistive properties. The indirect exchange interaction of the two TM atoms through a spacer of n carbon atoms determines the type of the magnetic ground state of these structures. The n-dependent variations of the ground state between ferromagnetic (F) and antiferromagnetic (AF) spin configurations exhibit several distinct features, including regular alternations and irregular forms. We present a simple analytical model that can successfully simulate these variations, and the induced magnetic moments on the carbon atoms. The periodically repeated TM-Cn atomic chains exhibit half-metallic properties with perfect spin polarization at the Fermi level (EF ). When connected to appropriate electrodes the TM-Cn-TM atomic chains act as molecular spin-valves in their F states due to the large ratios of the conductance values for each spin type. Secondly, a systematic study of the electronic and magnetic properties of TM atomic chains adsorbed on the zigzag single-wall carbon nanotubes (SWNTs) is presented. The adsorption on the external and internal wall of SWNT is considered and the effect of the TM coverage and geometry on the binding energy and the spin polarization at EF is examined. All those adsorbed chains studied have F ground state, but only their specific types and geometries demonstrated high spin polarization near EF . Their magnetic moment and binding energy in the ground state display interesting variation with the number of d−electrons of the TM atom. Spin-dependent electronic structure becomes discretized when TM atoms are adsorbed on finite segments of SWNTs. Once coupled with non-magnetic metal electrodes, these magnetic needles or nanomagnets can perform as spindependent resonant tunnelling devices. The electronic and magnetic properties of these nanomagnets can be engineered depending on the type and decoration of adsorbed TM atom as well as the size and symmetry of the tube. Finally, bare, hydrogen terminated and TM adsorbed Silicon nanowires (SiNW) oriented along [001] direction are investigated. An extensive analysis on the atomic structure, stability, elastic and electronic properties of bare and hydrogen terminated SiNWs is performed. It is then predicted that specific TM adsorbed SiNWs have a half-metallic ground state even above room temperature. At high coverage of TM atoms, ferromagnetic SiNWs become metallic for both spin-directions with high magnetic moment and may have also significant spin-polarization at EF . The spin-dependent electronic properties can be engineered by changing the type of adsorbed TM atoms, as well as the diameter of the nanowire. Most of these systems studied in this thesis appear to be stable at room temperature and promising for spintronic devices which can operate at ambient conditions. Therefore, we believe that present results are not only of academic interest, but also can initiate new research on spintronic applications of nanostructures.Durgun, EnginPh.D

Benchmarking a commercial (Sub-)THz focal plane array against a custom-built millimeter-wave single-pixel camera

For the first time, the characteristics of an evolving commercial camera technology that can operate at millimeter-wave frequencies has been independently investigated. In this work, we benchmark the TeraSense camera against a custom-built single-pixel camera at W-band, for image quality and aperture reflectance. It is found that the Tera-1024 TeraSense camera exhibits limited image resolution and fidelity, with significant levels of systematic spatial noise. In a poor signal-to-noise ratio scenario, the addition of random noise exacerbates these problems. Possible causes of both beam and image distortion have been identified in quasi-optical applications, which gives important insight into the best use of (sub-)THz cameras and interpretation of their images. Inherent standing waves caused by the significant power reflectance of the camera aperture is investigated in detail. A simple W-band one-port quasi-optical scalar network analyzer is developed, to determine the levels of reflectance for both cameras, with its bespoke calibration routine derived from first principles - providing a low-cost solution for many non-destructive testing applications. It is found that the TeraSense camera (with additional RAM) and single-pixel camera (having default RAM) have measured reflectance values of 27% and 3%, respectively, over a corresponding aperture area ratio of approximately 714:1. While our single-pixel camera provides excellent image resolution and fidelity, it inherently suffers from very slow raster-scanning speeds and operational bandwidth limitations. For this reason, the TeraSense camera technology is excellent for performing qualitative measurements in real time, with the caveats outlined in this paper