Amnon Yariv

Bio: Amnon Yariv is an academic researcher from California Institute of Technology. The author has contributed to research in topics: Laser & Semiconductor laser theory. The author has an hindex of 103, co-authored 1082 publications receiving 55256 citations. Previous affiliations of Amnon Yariv include University of California, Santa Barbara & Watkins-Johnson Company.

Corrugated laser structures

Abstract: GaAs–GaAlAs double-heterostructure injection lasers consist of several epilayers of GaAs and GaAlAs grown on a GaAs substrate. The need for cleaved end mirrors may be eliminated in these lasers by incorporating internal periodic corrugation which provide feedback. This distributed feedback relies on Bragg reflection from the periodic perturbation, and thus the lasing wavelength is directly proportional to the corrugation period. Such corrugated laser structures are compatible with the fabrication of monolithic optical circuits and seem to be most suitable as light sources for integrated optics. Our group prepared corrugated structures by ion milling or chemical etching through a photoresist mask which was generated by the interference of two laser beams. We observed laser emission from GaAs–GaAlAs double heterostructures with internal corrugation when pumped electrically at 77 °K. Theoretical considerations indicate that such lasers should have a very low threshold current and a good wavelength selectivity. Further experimental work on these devices is now in progress.

Chapter 2 Integrated Electronic and Photonic Devices

Abstract: Publisher Summary This chapter focuses on the integrated electronic and photonic devices. The electronic technology in semiconductor compound is dominated by GaAs field effect transistors (FETs) fabricated by direct implantation into the semi-insulating (SI) substrate. Heteroepitaxial technology is a must for optoelectronic devices. The blending of these separate technologies is achieved by the selective epitaxy technology. Double heterostructure (DH) transistor technology has advantages in speed and noise compared with FETs and the added bonus of being compatible with that of the laser. The heterobipolar transistor (HBT) achieves its maximum speed performance in stripe geometry at very high current densities and as an integrated circuit element, its area has to be reduced as much as possible. The main motivation for the development of GaAs ICs is speed. As speed increases, the interconnection of ICs and subsystems becomes more critical and cannot be easily implemented using technologies available today. Significant improvements in terms of speed and noise can be gained by the monolithic approach by reducing the importance of the role played by undesired packing parasitics associated with discrete devices.

Direct measurement of doping density and barrier lowering effect with bias in quantum wells

Abstract: An experimental method for determining the doping density in thin-sheet semiconductor material such as quantum wells (QWs) is demonstrated in GaAs/AlGaAs multiquantum-well infra-red photodetectors. The results agree very well with the conventional Hall measurement method. Barrier lowering effect with bias in QWs is determined experimentally.

Optically induced ferroelectric domain gratings in SBN: theory and applications to quasi-phase matching and optical data storage

Abstract: Illuminating a photoconducting strontium barium niobate crystal with a low intensity optical standing wave generates dynamic as well as remnant polarization gratings. We study the kinetics of these gratings and present a thermodynamic model for the grating formation. Fundamentally, light induced space charge fields dynamically modify the positions of ions within the unit cell and tailor the electronic, optical, and acoustic properties of the material.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

A comprehensive review of zno materials and devices

Abstract: The semiconductor ZnO has gained substantial interest in the research community in part because of its large exciton binding energy (60meV) which could lead to lasing action based on exciton recombination even above room temperature. Even though research focusing on ZnO goes back many decades, the renewed interest is fueled by availability of high-quality substrates and reports of p-type conduction and ferromagnetic behavior when doped with transitions metals, both of which remain controversial. It is this renewed interest in ZnO which forms the basis of this review. As mentioned already, ZnO is not new to the semiconductor field, with studies of its lattice parameter dating back to 1935 by Bunn [Proc. Phys. Soc. London 47, 836 (1935)], studies of its vibrational properties with Raman scattering in 1966 by Damen et al. [Phys. Rev. 142, 570 (1966)], detailed optical studies in 1954 by Mollwo [Z. Angew. Phys. 6, 257 (1954)], and its growth by chemical-vapor transport in 1970 by Galli and Coker [Appl. Phys. ...

Digital communications

Abstract: Spread Spectrum It’s not just for breakfast anymore! Don't blame me, the title is the work of this month's guest columnist, Steve Bible, N7HPR (n7hpr@tapr.org). While cruising the net recently, I noticed a sudden bump in the number of times Spread Spectrum (SS) techniques were mentioned in the amateur digital areas. While QEX has discussed SS in the past, we haven't touched on it in this forum. Steve was a frequent cogent contributor, so I asked him to give us some background. Steve enlisted in the Navy in 1977 and became a Data Systems Technician, a repairman of shipboard computer systems. In 1985 he was accepted into the Navy’s Enlisted Commissioning Program and attended the University of Utah where he studied computer science. Upon graduation in 1988 he was commissioned an Ensign and entered Nuclear Power School. His subsequent assignment was onboard the USS Georgia, a trident submarine stationed in Bangor, Washington. Today Steve is a Lieutenant and he is completing a master’s degree in computer science at the Naval Postgraduate School in Monterey, California. His areas of interest are digital communications, amateur satellites, VHF/UHF contesting, and QRP. His research area closely follows his interest in amateur radio. His thesis topic is Multihop Packet Radio Routing Protocol Using Dynamic Power Control. Steve is also the AMSAT Area Coordinator for the Monterey Bay area. Here's Steve, I'll have some additional comments at the end.

Plasmonics: Fundamentals and Applications

Abstract: Fundamentals of Plasmonics.- Electromagnetics of Metals.- Surface Plasmon Polaritons at Metal / Insulator Interfaces.- Excitation of Surface Plasmon Polaritons at Planar Interfaces.- Imaging Surface Plasmon Polariton Propagation.- Localized Surface Plasmons.- Electromagnetic Surface Modes at Low Frequencies.- Applications.- Plasmon Waveguides.- Transmission of Radiation Through Apertures and Films.- Enhancement of Emissive Processes and Nonlinearities.- Spectroscopy and Sensing.- Metamaterials and Imaging with Surface Plasmon Polaritons.- Concluding Remarks.