Download or read book Self mixing Interferometry for Absolute Distance Measurement written by Mengkoung Veng (docteur en photonique).) and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-mixing Interferometry has been studied extensively in the last five decades in various sensing applications. Sensors under the SMI technique have the laser diode as the light source, the interferometer, and the detector. The light from the laser diode propagates towards a distant target where it is partially reflected or back-scattered before being re-injected into the active cavity of the laser. When the laser diode experiences the external optical feedback, the reflected light imprinted with information from the distant target or from the external cavity medium induces perturbation to the operating parameters of the laser. For SMI measurement sensors such as harmonic motion and absolute distance applications, the fringe counting method is basically used to determine the target's displacement and distance respectively. Two different approaches to modelling the SMI phenomenon have been developed: the three-mirror cavity and the perturbation of the rate equation. The single equation that describes the phase condition imposed by the optical feedback is usually referred to as the excess phase equation. One of the most important and most useful parameters in the excess phase equation is the feedback parameter C as it can be used to qualitatively categorize the regime of the laser under optical feedback. When the feedback level C 1, the laser behaviour is stable. On the other hand, when the feedback level C 1, more complex phenomena are observed such as hysteresis effect, presence of multiple emission frequencies (including the unstable frequencies), apparent splitting of the emission line due to mode hopping and fringe disappearance phenomenon. The fringes disappearance phenomenon in the self-mixing interferometry occurs whenever the external round-trip phase at free-running state is modulated by either external modulation such as external cavity length changes or internal modulation when the laser injection current is modulated with a high back-scattered light power. This phenomenon has been observed by many authors for harmonic motion or vibration application and more recently in the case of the absolute distance measurement scheme when the laser injection current is modulated in the triangle waveform. This phenomenon is highly dependent on the feedback parameter C and it is described in detail based on the coupled cavity model. The primary cause for fringes disappearance is demonstrated to be the expansion of the excess phase equation stable solutions range with the increment of the parameter C, thus reducing the number of stable solutions for a given phase stimulus. This new approach in the modelling of the fringe disappearance phenomenon allows determination of the C values for which a pair of fringes are expected to disappear and as a consequence correlates the number of missing fringes to the value of C. This approach is validated both by a behavioural model of the laser under optical feedback and by a series of measurements in the SMI absolute distance configuration.

Download or read book Electro Optical Instrumentation written by Silvano Donati and published by Pearson Education. This book was released on 2004-04-09 with total page 636 pages. Available in PDF, EPUB and Kindle. Book excerpt: The complete, practical sourcebook for laser sensing and measurement This is a systematic, up-to-date guide to laser instrumentation for sensing and measurement in contemporary scientific, industrial, automotive and avionics applications. Dr. Silvano Donati presents clear design rules and useful hints for practical implementation of a wide variety of laser instruments. For each type of instrument, the author outlines basic principles, physical limitations, reasonable performance expectations, optical design issues, and electronic signal handling--illustrated with block schemes. Coverage includes: Interferometers for sub-micrometer displacement measurements Nanometer vibrometers and structural integrity testing Doppler velocimeters for anemometry of fluids Range finders and anti-collision systems Non-contact wire-diameter and particle-diameter sizing Alignment and level meter apparatuses Ring laser and optical fiber gyroscopes Optical fiber sensors Thorough and accessible, Electro-Optical Instrumentation offers balanced coverage of both optical and electronic issues and challenges. It will give working electronic engineers and scientists the knowledge they need to design virtually any electro-optical instrumentation system. PRENTICE HALL Upper Saddle River, NJ 07458 www.phptr.com

Download or read book Photonic Instrumentation written by Silvano Donati and published by CRC Press. This book was released on 2023-06-27 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photonic Instrumentation: Sensing and Measuring with Lasers is designed as a source for university-level courses covering the essentials of laser-based instrumentation, and as a useful reference for working engineers. Photonic instruments have very desirable features like non-contact operation and unparalleled sensitivity. They have quickly become a big industrial success, passing unaffected through the bubble years and, not any less important, well-established methods in measurement science. This book offers coverage of the most proven instruments, with a balanced treatment of the optical and electronic aspects involved. It also attempts to present the basic principles, develop the guidelines of design and evaluate the ultimate limits of performances set by noise. The instruments surveyed include: alignment instruments, such as wire diameter and particle size analyzers, telemeters, laser interferometers and self-mixing interferometers, and speckle pattern instruments, laser doppler velocimeters, gyroscopes, optical fiber sensors and quantum sensing. A few appendices offer convenient reference material for key principles on lasers, optical interferometers, propagation, scattering and diffraction.

Download or read book Absolute Distance Metrology Using Frequency Swept Lasers written by Matthew Stuart Warden and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes and evaluates two new interferometric distance measurement methods based upon the well known method of Frequency Scanning Interferometry (FSI). These new methods are known as Dynamic FSI and Cascaded FSI. Dynamic FSI addresses the two problems, commonly seen in previous FSI implementa- tions, of not being able to measure a moving target and having a slow measurement rate. This method measures stationary and moving targets equally well, and can determine the distance to the target at all times during the measurement, in contrast to previous methods, which obtain only a single measured length from a measurement process which can take up to a second to make. Cascaded FSI was developed with the aim of increasing the accuracy and precision of FSI. This method allows for measurements with precision equal to that of displacement interferometry, and also provides a way of measuring length relative to the frequencies of atomic absorption lines, which are inherently more stable length references than a physical length artefact.

Download or read book Interferometry in Speckle Light written by P. Jacquot and published by Springer Science & Business Media. This book was released on 2012-02-02 with total page 661 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings reflect the work presented at the conference "Interferometry in Speckle Light: Theory and Applications", held at the Ecole Polytechnique Federale de Lausanne, (EPFL), the Swiss Federal Institute of Technology in Lausanne, Switzerland. The event took place from September 25 to September 28, 2000. Thanks to the diligence of the authors, this book has been published just in time for the conference. Writing this preface in July, in anticipation of the conference, we have tried to envisage how this book will benefit the quality of discourse between authors and attendees. "Interferometry in Speckle Light: Theory and Applications" results from a bottom-up approach and is original in several ways. This conference is not part of a series; on the contrary, it is a single event. The idea of gathering scientists and engineers for a general discussion on the theory and the practice of interferometry, involving rough, non-optically polished objects, was "in the air". An opportunity of this sort was not provided by any of the conferences scheduled when the present one was conceived. For this reason, it was easy to convince a small number of renowned researchers, all of them active in the field of holographic and speckle interferometry, to organize a conference. To be specific, they are the people listed below as members of the scientific and local committees. At the same time, a particular circumstance, namely the retirement of Professor L. Pflug, helped to detennine the location of the meeting.

Download or read book Interferometry for High Resolution Absolute Distance Measuring by Larger Distances written by Ernst Dalhoff and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Unlocking Dynamical Diversity written by Deborah M. Kane and published by John Wiley & Sons. This book was released on 2005-11-01 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Applications of semiconductor lasers with optical feedback systems are driving rapid developments in theoretical and experimental research. The very broad wavelength-gain-bandwidth of semiconductor lasers combined with frequency-filtered, strong optical feedback create the tunable, single frequency laser systems utilised in telecommunications, environmental sensing, measurement and control. Those with weak to moderate optical feedback lead to the chaotic semiconductor lasers of private communication. This resource illustrates the diversity of dynamic laser states and the technological applications thereof, presenting a timely synthesis of current findings, and providing the roadmap for exploiting their future potential. * Provides theory-based explanations underpinned by a vast range of experimental studies on optical feedback, including conventional, phase conjugate and frequency- filtered feedback in standard, commercial and single-stripe semiconductor lasers * Includes the classic Lang-Kobayashi equation model, through to more recent theory, with new developments in techniques for solving delay differential equations and bifurcation analysis * Explores developments in self-mixing interferometry to produce sub-nanometre sensitivity in path-length measurements * Reviews tunable single frequency semiconductor lasers and systems and their diverse range of applications in sensing and optical communications * Emphasises the importance of synchronised chaotic semiconductor lasers using optical feedback and private communications systems Unlocking Dynamical Diversity illustrates all theory using real world examples gleaned from international cutting-edge research. Such an approach appeals to industry professionals working in semiconductor lasers, laser physics and laser applications and is essential reading for researchers and postgraduates in these fields.

Download or read book Optical Interferometry 2e written by P. Hariharan and published by Elsevier. This book was released on 2003-10-20 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: When the first edition of Optical Interferometry was published, interferometry was regarded as a rather esoteric method of making measurements, largely confined to the laboratory. Today, however, besides its use in several fields of research, it has applications in fields as diverse as measurement of length and velocity, sensors for rotation, acceleration, vibration and electrical and magnetic fields, as well as in microscopy and nanotechnology. Most topics are discussed first at a level accessible to anyone with a basic knowledge of physical optics, then a more detailed treatment of the topic is undertaken, and finally each topic is supplemented by a reference list of more than 1000 selected original publications in total. - Historical development of interferometry - The laser as a light source - Two-beam interference - Techniques for frequency stabilization - Coherence - Electronic phase measurements - Multiple-beam interference - Quantum effects in optical interference - Extensive coverage of the applications of interferometry, such as measurements of length, optical testing, interference microscopy, interference spectroscopy, Fourier-transform spectroscopy, interferometric sensors, nonlinear interferometers, stellar interferometry, and studies of space-time and gravitation

Download or read book Basics of Interferometry written by P. Hariharan and published by Academic Press. This book was released on 2012-12-02 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is for those who have some knowledge of optics, but little or no previous experience in interferometry. Accordingly, the carefully designed presentation helps readers easily find and assimilate the interferometric techniques they need for precision measurements. Mathematics is held to a minimum, and the topics covered are also summarized in capsule overviews at the beginning and end of each chapter. Each chapter also contains a set of worked problems that give a feel for numbers.The first five chapters present a clear tutorial review of fundamentals. Chapters six and seven discuss the types of lasers and photodetectors used in interferometry. The next eight chapters describe key applications of interferometry: measurements of length, optical testing, studies of refractive index fields, interference microscopy, holographic and speckle interferometry, interferometric sensors, interference spectroscopy, and Fourier-transform spectroscopy. The final chapter offers suggestions on choosing and setting up an interferometer.

Download or read book Semiconductor Lasers written by Junji Ohtsubo and published by Springer. This book was released on 2017-05-03 with total page 679 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the fascinating recent advances made concerning the chaos, stability and instability of semiconductor lasers, and discusses their applications and future prospects in detail. It emphasizes the dynamics in semiconductor lasers by optical and electronic feedback, optical injection, and injection current modulation. Applications of semiconductor laser chaos, control and noise, and semiconductor lasers are also demonstrated. Semiconductor lasers with new structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are intriguing and promising devices. Current topics include fast physical number generation using chaotic semiconductor lasers for secure communication, development of chaos, quantum-dot semiconductor lasers and quantum-cascade semiconductor lasers, and vertical-cavity surface-emitting lasers. This fourth edition has been significantly expanded to reflect the latest developments. The fundamental theory of laser chaos and the chaotic dynamics in semiconductor lasers are discussed, but also for example the method of self-mixing interferometry in quantum-cascade lasers, which is indispensable in practical applications. Further, this edition covers chaos synchronization between two lasers and the application to secure optical communications. Another new topic is the consistency and synchronization property of many coupled semiconductor lasers in connection with the analogy of the dynamics between synaptic neurons and chaotic semiconductor lasers, which are compatible nonlinear dynamic elements. In particular, zero-lag synchronization between distant neurons plays a crucial role for information processing in the brain. Lastly, the book presents an application of the consistency and synchronization property in chaotic semiconductor lasers, namely a type of neuro-inspired information processing referred to as reservoir computing.

Download or read book Adaptive Self mixing Interferometry for Metrology Applications written by Reza Atashkhooei and published by . This book was released on 2014 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Among the laser based techniques proposed for metrology applications, classical interferometers offer the highest precision measurements. However, the cost of some of the elements involved and the number of optical components used in the setup complicates using them in several industrial applications. Apart from cost, the complexities due to optical alignment and the required quality of the environmental conditions can be quite restrictive for those systems. Within the category of optical interferometers, optical feedback interferometry (OFI), also called self-mixing interferometry (SMI) has the potential to overcome some of the complexities of classical interferometry. It is compact in size, cost effective, robust, self-aligned, and it doesn't require a large number of optical components in the experimental configuration. In OFI, a portion of the emitted laser beam re-enters to the laser cavity after backreflection from the target, causing the wavelength of the laser to change, modifying the power spectrum and consequently the emitted output power, which can be detected for measurement purposes. Thus, the laser operates simultaneously as the light source, the light detector, and as the ultra-sensitive coherent sensor for optical path changes. The present PhD pursued improving the performance of OFI-based sensors using a novel and compact optical system. A solution using an adaptive optical element in the form of a voltage programmable liquid lens was proposed for automated focus adjustments. The amount of backreflected light re-entering the laser cavity could be controlled, and the laser feedback level was adjusted to the best condition in different situations, enabling the power signal to be adjusted to the best possible conditions for measurement. Feedback control enabled the proposal of a novel solution called differential OFI, which improved the measurement resolution down to the nanometre order, even if the displacements were below half-wavelength of the laser, for first time in OFI sensors. Another relevant part of the PhD was devoted to the analysis of speckle-affected optical power signals in feedback interferometers. Speckle effect appears when the displacements of the target are large, and introduces an undesired modulation of the amplitude of the signal. After an analysis of the speckle-affected signal and the main factors contributing to it, two novel solutions were proposed for the control of speckle noise. The adaptive optical head developed previously was used in a real time setup to control the presence of speckle effect, by tracking the signal to noise ratio of the emitted power, and modifying the spot size on the target when required using a feedback loop. Besides, a sensor diversity solution was proposed to enable enhancements in signal detection in fast targets, when real time control could not be applied. Finally, two industrial applications of the technique with the presence of different levels of speckle noise have been presented. A complete measurement methodology for the control of motor shaft runout in permanent magnet electrical motors, enabling complete monitoring of the displacement of the shaft has been developed and implemented in practice. Results here are validated with those obtained using a commercial laser Doppler vibrometer, an equipment with a much higher cost. A second application in the monitoring the displacement of polymer-reinforced beams used in civil engineering under dynamic loading was also demonstrated. Results here are validated using a conventional contact probe (a Linear Vertical Differential Transducer, LVDT). Both applications show that with controlled speckle features OFI performs adequately in industrial environments as a non-contact proximity probe with resolution limited by the constraints defined by the setup.

Download or read book Sensors and Microsystems written by Piero Malcovati and published by Springer Science & Business Media. This book was released on 2010-03-14 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sensors and Microsystems contains a selection of papers presented at the 14th Italian conference on sensors and microsystems. It provides a unique perspective on the research and development of sensors, microsystems and related technologies in Italy. The scientific values of the papers also offers an invaluable source to analyists intending to survey the Italian situation about sensors and microsystems. In an interdisciplinary approachm many aspects of the disciplines are covered, ranging from materials science, chemistry, applied physics, electronic engineering and biotechnologies. Further details of the conference and its full program at the website http://www.microelectronicsevents.com/AISEM

Download or read book Implementation of Differential Self mixing Interferometry Systems for the Detection of Nanometric Vibrations written by Francisco Javier Azcona Guerrero and published by . This book was released on 2018 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this Thesis, we explore Self-mixing interferometry (SMI ), a method capable of producing high resolution optical path related measurements in a simple, compact and cost-effective way. Even with a notably less complex setup than traditional interferometric methods, SMI can produce measurements with a resolution well below the micrometric scale (N'2) which is sufficient for most industrial applications. The SMI effect is produced when a small part of the laser power impacting a target is back-scattered and re-injected into the laser cavity. As a result, the phase and amplitude of the laser wave is modified generating a signature beat, which can be "easily" related to different optical path-related dynamics. The main advantage of this method in relation to other interferometric methods is the simple setup consisting mainly of a single mode laser diode (LO) equipped with a simple electronic system readout a simple optical system may be used to collimate/focus the beam allowing measurements at larger distances. Because of the small amount of reflected optical power required to allow the effect, the technique can produce high resolution measurements even with diffusive targets. While the SMI method has been largely studied in the last three decades, there are still several topics worth the development of further research. One of those topics, how to increase the resolution on displacement measurements, is one of the main topics covered in this work. Classical SMI methods allow the reconstruction of displacement measurement with a resolution of N'2. The use of special processing algorithms can push further this limit reaching values in the order of e.g. N32. In this work, we propose a method to increase even further this limit reach values better than N100.The idea discussed, differential self-mixing interferometry (OSMI) proposes the use of a reference modulation (mechanical or electrical) to be used as a reference for the measurement. Simulated results have shown that under ideal conditions, it may be possible to reach resolutions in the order of N1000. In practice, however, this limit is much smaller (N100) because of LO dynamics, and different practical limitations present in the amplification and readout electronics. Experiments and measurements are presented along the second chapter of this work to present proof of the proposed method. After exploring the basics of OSMI, possible applications for classic SMI and DSMI were pursued. The obtained results are presented in the following sections. First, a review on potential biomedical measurements using SMI is discussed. The obtained results suggest that it is possible to obtain some key values related to biomedical constants (e.g. P.PW) using a displacement SMI measurement. The method, however, may not be reliable enough especially on long time measurements. Moreover, the use of certain wavelengths must be avoided during long exposures as they may prove harmful to the soft tissue due to the requirements of a small laser spot. lt is observed that SNR may lead to difficulties during the signal processing stage which may impact the results of the reconstructed signal. Next, the DSMI method was tested in an AFM-like cantilever system. The results suggest that is possible to follow the motion of a micrometric size cantilever oscillating at low frequencies with a high resolution. Higher frequencies may be achieved by using an electronic reference modulation configuration. The proposed system was able to detect some artefacts on the motion which maybe attributed to possible deflections on the cantilever surface. Possible enhancements to the method are suggested for any researcher who wants to expand the topic.

Download or read book Handbook of Optical Dimensional Metrology written by Kevin Harding and published by Taylor & Francis. This book was released on 2016-04-19 with total page 497 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to their speed, data density, and versatility, optical metrology tools play important roles in today's high-speed industrial manufacturing applications. Handbook of Optical Dimensional Metrology provides useful background information and practical examples to help readers understand and effectively use state-of-the-art optical metrology methods

Download or read book Absolute Distance Interferometry Capable of Long term High Frequency Measurements of Fast Targets written by Andrew James Lancaster and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optical Metrology in Production Engineering written by Wolfgang Osten and published by SPIE-International Society for Optical Engineering. This book was released on 2004 with total page 814 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes Proceedings Vol. 7821

Download or read book Development of a Prototype Frequency Scanning Interferometric Absolute Distance Measurement System for the Survey Alignment of the International Linear Collider written by John Robert Green and published by . This book was released on 2007 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: