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Desenvolvimento de pentes de frequências ópticas para metrologia e espectroscopia de precisão; Development of optical frequency combs for precision metrology and spectroscopy

Giovana Trevisan Nogueira
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 15/02/2007 PT
Relevância na Pesquisa
26.15%
No final da década de 90, pentes de freqüências ópticas baseados em lasers de Ti:safira de modos travados tornaram-se uma importante ferramenta na área de metrologia. Eles têm sido usados, por exemplo, em medidas diretas de freqüências de várias centenas de THz e em relógios atômicos ópticos. Para a implementação de dois sistemas de pentes de freqüências ópticas, desenvolvemos neste trabalho dois lasers de Ti:safira de femtossegundos de alta taxa de repetição, que usam espelhos de varredura (chirped mirros) no lugar de prismas para compensar a dispersão em velocidade de grupo. Um dos lasers tem taxa de repetição em 770 MHz que pode ser facilmente ajustada entre 750 MHz and 1 GHz. A dispersão total da cavidade é de -60 fs2 , produzindo um espectro centrado em 780 nm com largura a meia altura em torno de 10 nm e pulsos de 150 fs. Este laser teve seu espectro alargado por duas fibra de microestrutura, cobrindo um intervalo de 510 à 1100 nm. O outro laser possui cavidade com taxa de repetição sintonizável entre 1 e 2,12 GHz, e um espectro que se estender de de 585 até 1200 nm a -20 dB abaixo do máximo em 986 nm sem o uso de fibra de microestrutura.A cavidade do laser tem dispersão total próxima de zero, porém com oscilações entre -50 a +100 fs2 entre 700 nm e 900 nm...

Contribuição para a medição automática por suporte de informação neutra e normalizada

Rodrigues, Luís Filipe Leite
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Trabalho de Conclusão de Curso
Publicado em //2012 POR
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26.27%
Dissertação de mestrado em Engenharia Mecânica; Dentro do ambiente fabril, existem diferentes células de fabrico, associadas a abordagens particulares, dependendo da sua função característica. O presente trabalho de investigação teve por objetivo o controlo da informação de forma neutra e normalizada na inspeção destas células de fabrico e da medição, mais especificamente no controlo da qualidade associado à verificação da circularidade de um furo ou de um veio. A integridade da informação, e a forma como é exposta, é da maior importância para a comunicação e desenvolvimento do problema, sendo que a utilização de informação de forma neutra e normalizada é uma mais-valia para qualquer utilizador destes sistemas, independentemente do equipamento, software ou sistema que seja utilizado. Assim, este trabalho explicita toda a informação do ponto de vista do projeto e as necessidades físicas que acompanham este sistema de medição, de modo a que informaticamente se consiga uma transladação da informação de forma coerente. Para tal, verifica-se que necessidades estão incutidas na comunicação e seus meios e formas, sendo posteriormente estudado o caso em estudo do ponto de vista da medição e todas as suas particularidades...

Effect of NaCl and HCl concentrations on primary pH measurement for the certification of standard materials

Souza,V.; Ordine,Alberto Pires; Fraga,I. C. S.; Getrouw,Monique Audrey; Borges,P. P.; Damasceno,J. C.; Couto,P. R. G.
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2006 EN
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26.15%
pH is an important parameter to control the production of food, medicine, petrochemical products and others. Thus, standard reference materials used to calibrate pH meters are necessary to guarantee reliability of the measurements. The Chemical Metrology Division (Dquim) of the National Metrology Institute of Brazil (Inmetro) has as one of its missions the certification of standard reference materials. In the case of pH, it will be done by the pH primary measurement system of Inmetro, in operation at Dquim since 2003. The buffer solution of nominal pH value equal to 6.865 will be the first to be certified. The study of some measurement parameters has already been accomplished, and will lead to the improvement of the primary pH measurement. In this paper, the effect of NaCl and HCl concentrations on the primary pH measurement is discussed, based on the results obtained by Inmetro in the regional comparison SIM 8.11P.

Strain Sensor of Carbon Nanotubes in Microscale: From Model to Metrology

Qiu, Wei; Li, Shi-Lei; Deng, Wei-lin; Gao, Di; Kang, Yi-Lan
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
Publicado em 10/02/2014 EN
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26.15%
A strain sensor composed of carbon nanotubes with Raman spectroscopy can achieve measurement of the three in-plane strain components in microscale. Based on previous work on the mathematic model of carbon nanotube strain sensors, this paper presents a detailed study on the optimization, diversification, and standardization of a CNT strain sensor from the viewpoint of metrology. A new miniaccessory for polarization control is designed, and two different preparing methods for CNT films as sensing media are introduced to provide diversified choices for applications. Then, the standard procedure of creating CNT strain sensors is proposed. Application experiments confirmed the effectiveness of the above improvement, which is helpful in developing this method for convenient metrology.

Coherent control of diamond defects for quantum information science and quantum sensing

Maurer, Peter
Fonte: Harvard University Publicador: Harvard University
Tipo: Thesis or Dissertation
EN_US
Relevância na Pesquisa
35.97%
Quantum mechanics, arguably one of the greatest achievements of modern physics, has not only fundamentally changed our understanding of nature but is also taking an ever increasing role in engineering. Today, the control of quantum systems has already had a far-reaching impact on time and frequency metrology. By gaining further control over a large variety of different quantum systems, many potential applications are emerging. Those applications range from the development of quantum sensors and new quantum metrological approaches to the realization of quantum information processors and quantum networks. Unfortunately most quantum systems are very fragile objects that require tremendous experimental effort to avoid dephasing. Being able to control the interaction between a quantum system with its local environment embodies therefore an important aspect for application and hence is at the focus of this thesis.; Physics

Legal metrology and the automotive air pollution control in Brazil

Cunha, Augusto Poças da; Azeredo, Ronaldo Nunes de
Fonte: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia Publicador: Inmetro - Instituto Nacional de Metrologia, Qualidade e Tecnologia
Tipo: Trabalho apresentado em evento / Paper
ENG
Relevância na Pesquisa
26.29%
4 f. : il.; This paper will present metrology’s role on air pollution control in Brazil, the benefits for society and how Inmetro’s Legal Metrology Directorate (Dimel, in its Portuguese acronym) is developing this work. Automotive vehicles are very significant air pollution source in Brazil [1]. To change this situation, two years later the Federal Government established the Automotive Vehicles Air Pollution Control Program (Proconve, in its Portuguese acronym), providing to the car manufacturers a gradual schedule to the implementation of cleaner automotive technologies on new vehicles. Today the exhaust emissions reduction for these vehicles is up to 97% [2]. For in-use vehicles, Proconve demanded to all Brazilian states the implementation of an Inspection and Maintenance (I/M) Program. At least once a year these vehicles should be submitted to an I/M authority to check its general conditions and to measure its exhaust emissions. The emissions measurement is performed with two different instruments: gas analyzers (for spark ignition engines) and opacimeters (for Diesel engines). Both instruments are under legal metrological control and are submitted to type evaluation and verification, performed by National Institute of Metrology...

Uma metodologia para redução de incertezas em sistema de medição de vazão de óleo e gás

Araújo, João de Deus Freire de
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Elétrica; Automação e Sistemas; Engenharia de Computação; Telecomunicações Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Elétrica; Automação e Sistemas; Engenharia de Computação; Telecomunicações
Tipo: Dissertação Formato: application/pdf
POR
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36.35%
The objective of this research is to discuss about the need for implementation of new alternatives for the implementation on the metrological control: on the findings of initial and subsequent measurements, the control procedures of measurement uncertainty applied in assessing the loss or remains found in handling operations of bulk liquids, when used turbine meters used in measuring the tax on the business of Petrobras, due to the current environment of legal metrology and scientific, both domestic and international. We aim, with these alternatives: standardizing the minimization of random and systematic errors, the estimate of the remaining errors, as well as the management control of metrological calibration procedures, control of measurement uncertainty, and contribute to the change in the form of performance of legal metrology and scientific disseminating new information to change management of metrological control, objectively focused on aspects of supervision in implementing these activities in the control of the uncertainties of measurement used in our processes in the fiscal measurement system Petrobras. Results are presented, information and comments on the influence of measurement uncertainty in the current results of the fiscal and transfer of custody. This will emphasize the need...

La cohérence conceptuelle d’étudiants collégiaux en mécanique newtonienne et en métrologie

Périard, Martin
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
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26.3%
Cette thèse porte sur l’évaluation de la cohérence du réseau conceptuel démontré par des étudiants de niveau collégial inscrits en sciences de la nature. L’évaluation de cette cohérence s’est basée sur l’analyse des tableaux de Burt issus des réponses à des questionnaires à choix multiples, sur l’étude détaillée des indices de discrimination spécifique qui seront décrits plus en détail dans le corps de l’ouvrage et sur l’analyse de séquences vidéos d’étudiants effectuant une expérimentation en contexte réel. Au terme de ce projet, quatre grands axes de recherche ont été exploré. 1) Quelle est la cohérence conceptuelle démontrée en physique newtonienne ? 2) Est-ce que la maîtrise du calcul d’incertitude est corrélée au développement de la pensée logique ou à la maîtrise des mathématiques ? 3) Quelle est la cohérence conceptuelle démontrée dans la quantification de l’incertitude expérimentale ? 4) Quelles sont les procédures concrètement mise en place par des étudiants pour quantifier l’incertitude expérimentale dans un contexte de laboratoire semi-dirigé ? Les principales conclusions qui ressortent pour chacun des axes peuvent se formuler ainsi. 1) Les conceptions erronées les plus répandues ne sont pas solidement ancrées dans un réseau conceptuel rigide. Par exemple...

Picometer level displacement metrology with digitally enhanced heterodyne interferometry

De Vine, Glenn; Rabeling, D; Slagmolen, Bram Johannes Jozef; Lam, Timothy; Chua, Sheon (SSSY); Wuchenich, Danielle; McClelland, David; Shaddock, Daniel
Fonte: http://www.osa.org/ Publicador: http://www.osa.org/
Tipo: Journal article; Published Version; Optical Society of America Formato: 10 pages
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Digitally enhanced heterodyne interferometry is a laser metrology technique employing pseudo-random codes phase modulated onto an optical carrier. We present the first characterization of the technique’s displacement sensitivity. The displacement of an optical cavity was measured using digitally enhanced heterodyne interferometry and compared to a simultaneous readout based on conventional Pound-Drever-Hall locking. The techniques agreed to within 5 pm/√Hz at 1 Hz, providing an upper bound to the displacement noise of digitally enhanced heterodyne interferometry. These measurements employed a real-time signal extraction system implemented on a field programmable gate array, suitable for closed-loop control applications. We discuss the applicability of digitally enhanced heterodyne interferometry for lock acquisition of advanced gravitational wave detectors.

Metrology in Chemistry: ICP-MS Analysis in Environmental Science.

PROHASKA Thomas; AREGBE YETUNDE; EVANS Peter
Fonte: Royal Society of Chemistry Publicador: Royal Society of Chemistry
Tipo: Articles in books Formato: Printed
ENG
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26.22%
Metrology in environmental science has gained significant importance over the last couple of years reflecting the need for quality control and harmonization of measurement results. Accreditation , new European directives and finally the highly competitive market require standards with respect to metrology and uncertainties attached to the measurement results. International measurement evaluation studies (.;g. IMEP- international measurement evaluation programme, organized by the EC-Joint Research Centre IRMM) underline the need of reliability and comparability of measurement results. It is well recognised in environmental science that the uncertainty of the measurement step is not necessarily the dominant factor. Nevertheless, many papers published in the field of environmental analysis continue to contain little or no information about the total uncertainty attached to the published values of the quality of results produced, which can only partially be explained by the lack of CRM. Isotope ratio analysis capabilities and the high sensitivity make ICP-MS an important tool in metrology. Isotope dilution mass spectrometry (ID-MS) leaves ICP-MS as method of choice, especially if several sample preparation steps are involved. Nonetheless...

A laser metrology system for precision pointing

Hospodar, Edward J.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado
Relevância na Pesquisa
26.34%
Approved for public release; distribution is unlimited; Precision spacecraft payloads are driving the need for fine pointing control and vibration cancellation. One implementation that provides pointing and disturbance control is the Stewart-Gough platform equipped with active sensing and actuating elements. The Precision Pointing Hexapod (PPH) at Naval Postgraduate School (NPS) is exactly such a platform initially installed with voice coil actuators and accelerometers on each strut by CSA Engineering Inc. High pointing accuracy, however, requires an additional external sensing system that feeds back the accurate location and orientation information of the moving platform for control. The first implementation by NPS of such sensing system is the eddy current metrology system. Currently, that system only provides measurement of the two degrees of motion that define the pointing direction and has issues such as questionable absolute pointing accuracy and lower resolution. This thesis seeks to develop a new laser metrology system, utilizing diode lasers and position sensing detectors, to provide all six degree of freedom information of the platform motion at higher precision and accuracy. The tasks of developing the laser metrology system from theory to design...

Development of a Hexapod Laser–Based Metrology Systems for a Finer Optical Beam Control

Chen, H.; Hospodar, E., Jr.; Agrawal, B.N.
Fonte: Escola de Pós-Graduação Naval Publicador: Escola de Pós-Graduação Naval
Relevância na Pesquisa
26.22%
The article of record as published may be found at http://dx.doi.org/10.2514/6.2004-3146; Free-Space Optical Communications requires stable and precise pointing on spacecraft to maintain optimal operating condition. One technology to achieve high precision pointing and steering for imaging or laser communication payload in the presence of vibrations is to make use of a Stewart platform with active struts. At the Spacecraft Research and Design Center (SRDC) of Naval Postgraduate School (NPS), a hexapod with voice coil actuators is equipped with in line accelerometers to perform the tasks of vibration isolation. For the tasks of pointing for optical payload, we adopted the approach of external measurement system, which provides directly the position and orientation information of the hexapod top platform. A laser metrology system, composed of three pairs of laser diodes and detectors, is design and fabricated at NPS. In this paper we document its development process, which includes the design, analysis, inspection and preliminary calibration effort.Free-Space Optical Communications requires stable and precise pointing on spacecraft to maintain optimal operating condition. One technology to achieve high precision pointing and steering for imaging or laser communication payload in the presence of vibrations is to make use of a Stewart platform with active struts. At the Spacecraft Research and Design Center (SRDC) of Naval Postgraduate School (NPS)...

Smart Feature Selection to enable Advanced Virtual Metrology

Lenz, Benjamin
Fonte: Universität Tübingen; Universität Tübingen Publicador: Universität Tübingen; Universität Tübingen
Tipo: Dissertation; info:eu-repo/semantics/doctoralThesis
EN
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36.53%
The present dissertation enhances the research in computer science, especially state of the art Machine Learning (ML), in the field of process development in Semiconductor Manufacturing (SM) by the invention of a new Feature Selection (FS) algorithm to discover the most important equipment and context parameters for highest performance of predicting process results in a newly developed advanced Virtual Metrology (VM) system. In complex high-mixture-low-volume SM, chips or rather silicon wafers for numerous products and technologies are manufactured on the same equipment. Process stability and control are key factors for the production of highest quality semiconductors. Advanced Process Control (APC) monitors manufacturing equipment and intervenes in the equipment control if critical states occur. Besides Run-To-Run (R2R) control and Fault Detection and Classification (FDC) new process control development activities focus on VM which predicts metrology results based on productive equipment and context data. More precisely, physical equipment parameters combined with logistical information about the manufactured product are used to predict the process result. The compulsory need for a reliable and most accurate VM system arises to imperatively reduce time and cost expensive physical metrology as well as to increase yield and stability of the manufacturing processes while concurrently minimizing economic expenditures and associated data flow. The four challenges of (1) efficiency of development and deployment of a corporate-wide VM system...

Beam alignment and image metrology for scanning beam interference lithography : fabricating gratings with nanometer phase accuracy

Chen, Carl Gang, 1972-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 285 p.; 9028353 bytes; 9028236 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
26.45%
We are developing a scanning beam interference lithography (SBIL) system. SBIL is capable of producing large-area linear diffraction gratings that are phase-accurate to the nanometer level. Such gratings may enable new paradigms in fields such as semiconductor pattern placement metrology and grating-based displacement measuring interferometry. With our prototype tool nicknamed "Nanoruler", I have successfully patterned, for the first time, a 400 nm period grating over a 300 mm-diam. wafer, the largest that the tool can currently accommodate. By interfering two small diameter Gaussian laser beams to produce a low-distortion grating image, SBIL produces large gratings by step-and-scanning the photoresist-covered substrate underneath the image. To implement SBIL, two main questions need to be answered: First, how does one lock the interference image to a fast-moving substrate with nanometer accuracy? Secondly, how does one produce an interference image with minimum phase nonlinearities while setting and holding its period to the part-per-million (ppm) level? My thesis work solves the latter problem, which can be further categorized into two parts: period control and wavefront metrology. Period control concerns SBIL's ability to set, stabilize and measure the image grating period. Our goal is to achieve control at the ppm level in order to reduce any related phase nonlinearity in the exposed grating to subnanometers. A grating beamsplitter is used to stabilize the period. I demonstrate experimental results where the period stabilization is at the 1 ppm level. An automated beam alignment system is built. The system can overlap the beam centroids to around 10 [mu]m and equalize the mean beam angles to better than 2 [mu]rad (0.4 arcsec)...

Staged attitude-metrology pointing control and parametric integrated modeling for space-based optical systems

Lim, Ryan S. (Ryan Seungwook)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 158 p.; 8872484 bytes; 9462463 bytes; application/pdf; application/pdf
ENG
Relevância na Pesquisa
26.22%
The quest for higher sensitivity and finer angular resolution in astronomy demands larger and more complex space imaging systems. This thesis presents the concepts developed for two different technologies that have the potential to contribute in improving the performance of space imaging systems. The first technology is precision pointing control technology, which can provide fine optical control operating in conjunction with coarse formation flying attitude control in order to meet the stringent optical requirements. This will potentially enable a long baseline Formation Flying Interferometer (FFI) such as NASA's Terrestrial Planet Finder (TPF). The concept for precision pointing control was realized by a testbed called the Precision Pointing Optical Payload (PPOP). The design and implementation of the PPOP are described, followed by an experimental demonstration of staged pointing control. The global metrology system of the Synchronized Position Hold Engage Reorient Experimental Satellites (SPHERES) provides coarse attitude control, whereas the PPOP provides fine pointing control using a set of fast steering mirrors. The second technology investigates parametric integrated modeling of space telescopes.; (cont.) This technology provides a design tool for examining alternative telescope architectures and identifying favorable architectures at an early stage of the design lifecycle. The MIT Space Systems Laboratory (MIT-SSL) is currently developing a parametric integrated model for a Modular Optical Space Telescope (MOST). This thesis provides an overview of the MOST model...

Digital laser frequency control and phase stabilization loops for a high precision space-borne metrology system

Hechenblaikner, Gerald; Wand, Vinzenz; Kersten, Michael; Danzmann, Karsten; Garcia, Antonio; Heinzel, Gerhard; Nofrarias, Miquel; Steier, Frank
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 21/05/2012
Relevância na Pesquisa
26.23%
We report on the design, implementation and characterization of fully digital control loops for laser frequency stabilization, differential phase-locking and performance optimization of the optical metrology system on-board the LISA Pathfinder space mission. The optical metrology system consists of a laser with modulator, four Mach-Zehnder interferometers, a phase-meter and a digital processing unit for data analysis. The digital loop design has the advantage of easy and flexible controller implementation and loop calibration, automated and flexible locking and resetting, and improved performance over analogue circuitry. Using the practical ability of our system to modulate the laser frequency allows us to accurately determine the open loop transfer function and other system properties. Various noise sources and their impact on system performance are investigated in detail.; Comment: 10 pages, 7 figures; draft only, for edited version see journal link

A low cost scheme for high precision dual-wavelength laser metrology

Kok, Yitping; Ireland, Michael J.; Robertson, J. Gordon; Tuthill, Peter G.; Warrington, Benjamin A.; Tango, William J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/03/2013
Relevância na Pesquisa
26.36%
A novel method capable of delivering relative optical path length metrology with nanometer precision is demonstrated. Unlike conventional dual-wavelength metrology which employs heterodyne detection, the method developed in this work utilizes direct detection of interference fringes of two He-Ne lasers as well as a less precise stepper motor open-loop position control system to perform its measurement. Although the method may be applicable to a variety of circumstances, the specific application where this metrology is essential is in an astrometric optical long baseline stellar interferometer dedicated to precise measurement of stellar positions. In our example application of this metrology to a narrow-angle astrometric interferometer, measurement of nanometer precision could be achieved without frequency-stabilized lasers although the use of such lasers would extend the range of optical path length the metrology can accurately measure. Implementation of the method requires very little additional optics or electronics, thus minimizing cost and effort of implementation. Furthermore, the optical path traversed by the metrology lasers is identical with that of the starlight or science beams, even down to using the same photodetectors...

Stability analysis of semiconductor manufacturing process with EWMA run-to-run controllers

Ai, Bing; Wong, David Shan-Hill; Jang, Shi-Shang
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 29/10/2015
Relevância na Pesquisa
26.22%
In the semiconductor manufacturing batch processes, each step is a complicated physiochemical batch process; generally it is difficult to perform measurements online or carry out the measurement for each run, and hence there will be delays in the feedback of the system. The effect of the delay on the stability of the system is an important issue which needs to be understood. Based on the exponentially weighted moving average (EWMA) algorithm, we propose two kinds of controllers, EWMA-I and II controllers for single product process and mixed product process in semiconductor manufacturing in this paper. For the single product process, the stabilities of systems with both controllers which undergo different kinds of metrology delays are investigated. Necessary and sufficient conditions for the stochastic stability are established. Routh-Hurwitz criterion and Lyapunov's direct method are used to obtain the stability regions for the system with fixed metrology delay. By using Lyapunov's direct method, the stability region is established for the system with fixed sampling metrology and with stochastic metrology delay. We also extended the theorems of single product process to mixed product process. Based on the proposed theorems, some numerical examples are provided to illustrate the stability of the delay system.

Quantum State Engineering and Precision Metrology using State-Insensitive Light Traps

Ye, Jun; Kimble, H. J.; Katori, Hidetoshi
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
26.23%
Precision metrology and quantum measurement often demand matter be prepared in well defined quantum states for both internal and external degrees of freedom. Laser-cooled neutral atoms localized in a deeply confining optical potential satisfy this requirement. With an appropriate choice of wavelength and polarization for the optical trap, two electronic states of an atom can experience the same trapping potential, permitting coherent control of electronic transitions independent of the atomic center-of-mass motion. We review a number of recent experiments that use this approach to investigate precision quantum metrology for optical atomic clocks and coherent control of optical interactions of single atoms and photons within the context of cavity quantum electrodynamics. We also provide a brief survey of promising prospects for future work.; Comment: 23 pages of main text, 4 figures, and 12 pages of Supporting Online Material (SOM)

On-chip probe metrology

Farner, William Robert
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
36.15%
The semiconductor market was valued at over $270 billion in 2007, with projections to continue steady growth [7]. Any manufacturing process of this volume is tightly controlled to ensure high efficiency, and improvements are readily sought after. Despite semiconductor fabrication process advancements allowing circuits to contain larger numbers of transistors in smaller package sizes, there has not been any significant change in the way these circuits interface with test systems before packaging. This limitation causes the area overhead occupied by circuit contacts, known as bond pads, to become increasingly costly. To amend the situation, VLSI designers have attempted to reduce bond pads size and pitch as much as possible while retaining reliable probing accuracy [15]. Currently, there is no standard solution to assess the accuracy of probe stations inline with wafer testing. As such, a balance must be struck between overhead cost of large bond pads and operational cost spent analyzing probe performance off-line. A feedback loop on probe card performance during wafer fabrication sort could allow plants to recalibrate probe cards before a yield drop is detected, thus improving yield and saving operational costs [26]. This thesis demonstrates a proof of concept design that offers a viable solution to perform probe metrology in-line with wafer-level circuit testing. A versatile circuit was designed and laid out that promises fine accuracy resolution of 3.21 μm...