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 …

I and i

다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Part I. Fundamental Concepts: 1. Introduction and overview 2. Introduction to quantum mechanics 3. Introduction to computer science Part II. Quantum Computation: 4. Quantum circuits 5. The quantum Fourier transform and its application 6. Quantum search algorithms 7. Quantum computers: physical realization Part III. Quantum Information: 8. Quantum noise and quantum operations 9. Distance measures for quantum information 10. Quantum error-correction 11. Entropy and information 12. Quantum information theory Appendices References Index.

Quantum Computation and Quantum Information

Current research into semiconductor clusters is focused on the properties of quantum dots-fragments of semiconductor consisting of hundreds to many thousands of atoms-with the bulk bonding geometry and with surface states eliminated by enclosure in a material that has a larger band gap. Quantum dots exhibit strongly size-dependent optical and electrical properties. The ability to join the dots into complex assemblies creates many opportunities for scientific discovery.

Semiconductor Clusters, Nanocrystals, and Quantum Dots

Recent years have witnessed many breakthroughs in research on graphene (the first two-dimensional atomic crystal) as well as a significant advance in the mass production of this material. This one-atom-thick fabric of carbon uniquely combines extreme mechanical strength, exceptionally high electronic and thermal conductivities, impermeability to gases, as well as many other supreme properties, all of which make it highly attractive for numerous applications. Here we review recent progress in graphene research and in the development of production methods, and critically analyse the feasibility of various graphene applications.

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A roadmap for graphene

We experimentally observe the "superprism effect" in a periodic thin-film structure acting as a one-dimensional photonic crystal. The design of non-periodic structures exhibiting a linear shift with wavelength in the EDFA C-band is discussed. 2002 Optical Society of America OCIS codes: (260.2030) Dispersion; (060.4230) Multiplexing; (230.4170) Multilayers WDM systems create a strong need for compact wavelength splitting devices that can be easily manufactured. Here we demonstrate the capability of group velocity effects in multilayer dielectric structures to provide wavelength splitting. In contrast to typical dielectric interference filters, in this approach, one multilayer structure can separate multiple beams of different wavelengths. We demonstrate beam shifts with wavelength in a periodic multilayer stack; such a structure can also be viewed as a one- dimensional photonic crystal. We also extend the analysis to design non-periodic structures with superior wavelength splitting properties. One-dimensional (1,2), two-dimensional (1), and three-dimensional (3) photonic crystals exhibit strong dispersion at wavelengths close to the stop band (i.e., the reflection band in such a structure when used as a mirror). This "superprism effect" can be used to spatially separate beams of different wavelength. We focus on one-dimensional structures, as they are easy to fabricate with well-known technology allowing for compact, cost-effective WDM devices. Fig. 1 shows a schematic of our periodic thin-film device. Light is incident onto the dielectric stack from the substrate side. Close to the stop band, different wavelengths propagate at different angles within the periodic stack. Thus, beams of different wavelength are spatially separated along the x-direction. In order to achieve a higher separation, multiple bounces can be performed in the stack.

/pdf/thin-film-wavelength-demultiplexer-based-on-photonic-crystal-390ihxb8qu.pdf

Thin-film wavelength demultiplexer based on photonic crystal and group velocity effects

Zone-melting-recrystallized (ZMR) silicon on insulator (SOX) typically employs graphite strip heaters or other low power density melting sources with relatively slow scanning speeds [l] . The results of thermal modeling simulations suggest that high quality SO1 can also be obtained by high power density, line-source rapid zone recrystallization 121. The advantage to rapid recrystallization is the shorter high temperature duration, with less damage to existing structures or impurity distributions in the sample and greater applicability to 3-D IC's. To date, only line-source electron-beams [3] have been used for rapid recrystallization. This paper present! electrical measurements from active devices fabricated in SO1 material processed in a rapid zone recrystallization system using ; pulsed arc lamp line source. The seeded polysilicon coated sample is rapidly preheated (above lOOO\"C, in room air ambient) and scanned by a linear translatior. table under the zone; speed is of the order of 35 cm . s-'. (BJ comparison, strip heater ZMR systems typically operate at 100 1% . cm-' with scan speeds of 1 mm * s-'.) The lamp energy is C O L limated by a plate optic to a 0.5-mm line with 8-kW . cm-' powel. density. A single lamp pulse melts the top film and the sample then cools by radiation. The sample is above room temperature for less: than 15 s. The experimental apparatus and materials properties art: reported elsewhere [4]. Three-inch Si wafers with 0.5-pm-thicl: seeded SO1 islands (50 pm by 2.5 cm) were prepared by thir; method. MOSFET's, resistors, capacitors, lateral junction diodes, Schottky diodes, and MESFET's were fabricated; standard CMOS LOCOS process technology was employed. Measurements reveal electron mobilities averaging 670 cm2 . 1' 1 s in implanted channels (15 percent higher than in bulk monito : samples). Unpassivated backchannel leakage av'eraged 80 nA pm-'. Minority-carrier lifetimes over 10 p s (comparable to line e beam recrystallized samples) exceed the values commonly seen in ZMR material. The electrical results confirm the material qualit!! suggested by SEM, TEM, and Nomarski observations. Reproducible results were obtained in FET's down to 1-pm effective chamne1 length. The process, with significantly higher throughput than one requiring a vacuum, has application to high-speed, dense, radiation-hard CMOS.

IIIA-1 high-frequency GaInAs/InP multiple quantum well buried mesa electroabsorption optical modulator

We have demonstrated wavelength separation using a dielectric stack, and suggest that this fundamental property of one-dimensional photonic crystals can be exploited to create a compact, highly dispersive device for WDM. In contrast to previously suggested devices, this one-dimensional structure is simple and inexpensive to fabricate and is made from readily available materials. Additionally, because of the inherent scalability of photonic crystal properties, such a device could be designed for use at any wavelength of interest. We note also that it is not essential that the device be periodic. Many other layered structures with substantial group velocity dispersion would appear to be possible.

Wavelength demultiplexing by beam shifting using a dielectric stack as a one-dimensional photonic crystal

We present a novel MSM (metal-semiconductor-metal) based tunable photodetector for discrimination between two wavelengths with a 365 GHz channel spacing. If integrated with CMOS circuits, this photodetector has the potential to perform high-speed channel switching in WDM-based systems.

/pdf/novel-electrically-tunable-msm-photodetector-for-resolving-25n6yp6mcd.pdf

Novel electrically tunable MSM photodetector for resolving WDM channels

A tunable laser whose lasing frequency can be changed by varying the absorbance of absorber layers (1041 1042) that are placed in a standing wave of the laser cavity. Changes in the absorbance of the layers are accomplished by varying the strength of the absorber layers through application of voltage to the layers.

David A. B. Miller

Papers

Thin-film wavelength demultiplexer based on photonic crystal and group velocity effects

IIIA-1 high-frequency GaInAs/InP multiple quantum well buried mesa electroabsorption optical modulator

Wavelength demultiplexing by beam shifting using a dielectric stack as a one-dimensional photonic crystal

Novel electrically tunable MSM photodetector for resolving WDM channels

Tunable lasers based on absorbers in standing waves