Download or read book Adaptive Optics Using MEMS Deformable Mirrors written by Dhiraj Hiro Malkani and published by . This book was released on 2000 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book MEMS Deformable Mirrors for Adaptive Optics written by Raji Krishnamoorthy Mali and published by . This book was released on 1999 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Design Fabrication and Characterization of MEMS Deformable Mirrors for Ocular Adaptive Optics written by Hyunkyu Park and published by . This book was released on 2009 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modelling MEMS Deformable Mirrors for Astronomical Adaptive Optics written by Célia Blain and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As of July 2012, 777 exoplanets have been discovered utilizing mainly indirect detection techniques. The direct imaging of exoplanets is the next goal for astronomers, because it will reveal the diversity of planets and planetary systems, and will give access to the exoplanet's chemical composition via spectroscopy. With this spectroscopic knowledge, astronomers will be able to know, if a planet is terrestrial and, possibly, even find evidence of life. With so much potential, this branch of astronomy has also captivated the general public attention. The direct imaging of exoplanets remains a challenging task, due to (i) the extremely high contrast between the parent star and the orbiting exoplanet and (ii) their small angular separation. For ground-based observatories, this task is made even more difficult, due to the presence of atmospheric turbulence. High Contrast Imaging (HCI) instruments have been designed to meet this challenge. HCI instruments are usually composed of a coronagraph coupled with the full on-axis corrective capability of an Extreme Adaptive Optics (ExAO) system. An efficient coronagraph separates the faint planet's light from the much brighter starlight, but the dynamic boiling speckles, created by the stellar image, make exoplanet detection impossible without the help of a wavefront correction device. The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system is a high performance HCI instrument developed at Subaru Telescope. The wavefront control system of SCExAO consists of three wavefront sensors (WFS) coupled with a 1024-actuator Micro-Electro-Mechanical-System (MEMS) deformable mirror (DM). MEMS DMs offer a large actuator density, allowing high count DMs to be deployed in small size beams. Therefore, MEMS DMs are an attractive technology for Adaptive Optics (AO) systems and are particularly well suited for HCI instruments employing ExAO technologies. SCExAO uses coherent light modulation in the focal plane introduced by the DM, for both wavefront sensing and correction. In this scheme, the DM is used to introduce known aberrations (speckles in the focal plane), which interfere with existing speckles. By monitoring the interference between the pre-existing speckles and the speckles added deliberately by the DM, it is possible to reconstruct the complex amplitude (amplitude and phase) of the focal plane speckles. Thus, the DM is used for wavefront sensing, in a scheme akin to phase diversity. For SCExAO and other HCI systems using phase diversity, the wavefront compensation is a mix of closed-loop and open-loop control of the DM. The successful implementation of MEMS DMs open-loop control relies on a thorough modelling of the DM response to the control system commands. The work presented in this thesis, motivated by the need to provide accurate DM control for the wavefront control system of SCExAO, was centred around the development of MEMS DM models. This dissertation reports the characterization of MEMS DMs and the development of two efficient modelling approaches. The open-loop performance of both approaches has been investigated. The model providing the best result has been implemented within the SCExAO wavefront control software. Within SCExAO, the model was used to command the DM to create focal plane speckles. The work is now focused on using the model within a full speckle nulling process and on increasing the execution speed to make the model suitable for on-sky operation.
Download or read book Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems written by Zhizheng Wu and published by Springer Science & Business Media. This book was released on 2012-10-22 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems presents a novel design of wavefront correctors based on magnetic fluid deformable mirrors (MFDM) as well as corresponding control algorithms. The presented wavefront correctors are characterized by their linear, dynamic response. Various mirror surface shape control algorithms are presented along with experimental evaluations of the performance of the resulting adaptive optics systems. Adaptive optics (AO) systems are used in various fields of application to enhance the performance of optical systems, such as imaging, laser, free space optical communication systems, etc. This book is intended for undergraduate and graduate students, professors, engineers, scientists and researchers working on the design of adaptive optics systems and their various emerging fields of application. Zhizheng Wu is an associate professor at Shanghai University, China. Azhar Iqbal is a research associate at the University of Toronto, Canada. Foued Ben Amara is an assistant professor at the University of Toronto, Canada.
Download or read book Adaptive Optics Ophthalmologic Systems Using Dual Deformable Mirrors written by and published by . This book was released on 2007 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive Optics (AO) have been increasingly combined with a variety of ophthalmic instruments over the last decade to provide cellular-level, in-vivo images of the eye. The use of MEMS deformable mirrors in these instruments has recently been demonstrated to reduce system size and cost while improving performance. However, currently available MEMS mirrors lack the required range of motion for correcting large ocular aberrations, such as defocus and astigmatism. In order to address this problem, we have developed an AO system architecture that uses two deformable mirrors, in a woofer/tweeter arrangement, with a bimorph mirror as the woofer and a MEMS mirror as the tweeter. This setup provides several advantages, including extended aberration correction range, due to the large stroke of the bimorph mirror, high order aberration correction using the MEMS mirror, and additionally, the ability to ''focus'' through the retina. This AO system architecture is currently being used in four instruments, including an Optical Coherence Tomography (OCT) system and a retinal flood-illuminated imaging system at the UC Davis Medical Center, a Scanning Laser Ophthalmoscope (SLO) at the Doheny Eye Institute, and an OCT system at Indiana University. The design, operation and evaluation of this type of AO system architecture will be presented.
Download or read book Micro deformable Mirrors for Adaptive Optics Applications written by Emily Jo Carr and published by . This book was released on 2006 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Analysis of Diffraction Effects from a Segmented MEMS Deformable Mirror for a Closed Loop Adaptive Optics System written by and published by . This book was released on 2010 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Micro-Electro-Machined Systems (MEMS) have been increasingly used as mirrors in place of conventional continuous face sheet deformable mirrors (DM) in adaptive optics (AO) systems. Here we study the diffraction effects introduced into the optical path when a segmented MEMS DM is used to correct for the wavefront aberrations. Diffraction effects are monitored through the intermediate focus plane prior to the wavefront sensor. Low pass spatial filter is used at the plane in order to investigate how the making of various diffraction orders affects the phase. Measured phase and focal image plane data for various turbulence conditions are presented and analyzed.
Download or read book Memorial ajustado hecho en virtud de auto del Consejo del pleyto pendiente en el entre Don Andres Tellez Giron Duque de Uceda Don Luis Fernandez de Cordova Espinola de la Cerda Duque de Medina Celi Don Francisco de Paula Cordova Pacheco Portocarrero y Cardenas como marido de Do a Isabel Maria Pacheco Portocarrero y Cardenas Marquesa de la Torre de las Sergadas y D Joseph Manuel de Esquivel Rivas y Verastegui como marido de Do a Antonia Xaviera de Cardenas y Peralta Marquesa de Legarda sobre la Tenuta y Possession de los Mayorazgos del Aguij n Torre del Fresno Torre del Aguila y Villa de Lob n fundados por Don Alonso de Cardenas y Do a Elvira de Figueroa su muger Condes de la Puebla del Maestre vacantes por muerte de la Condesa de Monte nuevo written by and published by . This book was released on 1765* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Demonstrating Optical Aberration Correction with a Mems Micro Mirror Device written by Shaun Roger Hick and published by . This book was released on 1996-12-01 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research conducted the first demonstrated use of a micro- electro-mechanical structure (MEMS) mirror array to correct a static optical aberration. A well developed technique in adaptive optics imaging systems uses a deformable mirror to reflect the incident wave front to the imaging stage of the system. By matching the surface of the deformable mirror to the shape of the wave front phase distortion, the reflected wave front will be less aberrated before it is imaged. Typical adaptive optics systems use piezo-electric actuated deformable mirrors. This research used an electrostatically actuated, segmented mirror array, constructed by standard MEMS fabrication techniques, to investigate its performance as a deformable mirror. The relatively cheap cost of MEMS fabrication promises new adaptive optics applications if a suitable design can be found. In the demonstration, the point spread function (PSF) of the corrected and uncorrected aberrated image were compared. A 43 percent improvement in the peak intensity of the PSF was noted in the corrected image.
Download or read book Extreme Adaptive Optics Testbed written by J. W. Evans and published by . This book was released on 2005 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: ''Extreme'' adaptive optics systems are optimized for ultra-high-contrast applications, such as ground-based extrasolar planet detection. The Extreme Adaptive Optics Testbed at UC Santa Cruz is being used to investigate and develop technologies for high-contrast imaging, especially wavefront control. We use a simple optical design to minimize wavefront error and maximize the experimentally achievable contrast. A phase shifting diffraction interferometer (PSDI) measures wavefront errors with sub-nm precision and accuracy for metrology and wavefront control. Previously, we have demonstrated RMS wavefront errors of 1.5 nm and a contrast of10{sup 7} over a substantial region using a shaped pupil without a deformable mirror. Current work includes the installation and characterization of a 1024-actuator Micro-Electro-Mechanical-Systems (MEMS) deformable mirror, manufactured by Boston Micro-Machines for active wavefront control. Using the PSDI as the wavefront sensor we have flattened the deformable mirror to 1 nm within the controllable spatial frequencies and measured a contrast in the far field of10{sup 6}. Consistent flattening required testing and characterization of the individual actuator response, including the effects of dead and low-response actuators. Stability and repeatability of the MEMS devices was also tested. Ultimately this testbed will be used to test all aspects of the system architecture for an extrasolar planet-finding AO system.
Download or read book Field Guide to Adaptive Optics written by Robert K. Tyson and published by SPIE-International Society for Optical Engineering. This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a summary of the methods for determining the requirements of an adaptive optics system, the performance of the system, and the requirements for the components of the system. This second edition has a greatly expanded presentation of adaptive optics control system design and operation. Discussions of control models are accompanied by various recommendations for implementing the algorithms in hardware.
Download or read book Adaptive Optics in Astronomy written by François Roddier and published by Cambridge University Press. This book was released on 1999-06-17 with total page 421 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics is set to revolutionise the future of astronomy; this is the first book on the subject and is set to become the standard reference.
Download or read book The Simplest Test of Target Zone Credibility written by and published by . This book was released on 1990 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Adaptive Optics for Industry and Medicine written by Ulrich Wittrock and published by Springer Science & Business Media. This book was released on 2006-01-20 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 4th International Workshop on Adaptive Optics for Industry and Me- cine took place in Munster, ̈ Germany, from October 19 to October 24, 2003. The series of International Workshops on Adaptive Optics for Industry and Medicine beganwiththe?rstworkshopinShatura/Russiain1997,thesecond workshop took place in Durham/England in 1999, and the third workshop was held in Albuquerque/USA in 2001. The workshop series started out as a true grassroots movement and kept an informal spirit throughout all four workshops. Many personal friendships and scienti?c collaborations have been formed at these meetings. This fourth workshop was supposed to be held in Beijing, China. H- ever, the program committee decided in May 2003 to move the workshop to Munster ̈ due the general perception that the SARS (Severe Acute R- piratory Syndrome) cases reported in China could lead to a large epidemic. Despite this rather short notice the workshop in Munster ̈ was attended by about 70 people. Incidentally, the workshop coincided with the 50th anniv- sary of adaptive optics, because it was October 1953 when Horace Babcock published his famous paper “The possibilities of compensating astronomical seeing” in the Publications of the Astronomical Society of the Paci?c.
Download or read book MOEMS written by M. Edward Motamedi and published by SPIE Press. This book was released on 2005 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the exciting and fast-moving field of MOEMS to graduate students, scientists, and engineers by providing a foundation of both micro-optics and MEMS that will enable them to conduct future research in the field. Born from the relatively new fields of MEMS and micro-optics, MOEMS are proving to be an attractive and low-cost solution to a range of device problems requiring high optical functionality and high optical performance. MOEMS solutions include optical devices for telecommunication, sensing, and mobile systems such as v-grooves, gratings, shutters, scanners, filters, micromirrors, switches, alignment aids, lens arrays, and hermetic wafer-scale optical packaging. An international team of leading researchers contributed to this book, and it presents examples and problems employing cutting-edge MOEM devices. It will inspire researchers to further advance the design, fabrication, and analysis of MOEM systems.
Download or read book Efficient Drive Electronics for Deformable Mirrors of Telescope Adaptive Optics Systems written by Joel Niebergal and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis deals with the design and experimental validation of Deformable Mirror Electronics (DME) for Extremely Large Telescope (ELT) Adaptive Optics (AO) applications. Modern ground based telescopes achieve their best possible imaging resolution through the application of AO. However, due to the fundamental diffraction of optical elements, the next generation of ELTs will employ primary mirrors of an increasingly large diameter as the final means of improving imaging resolution further. The corresponding increase in diameter and actuator count of the Deformable Mirrors (DMs) in these systems has led to the rapid development of high order DM technology. A significant challenge to operating these multi-thousand channel DMs is related to the DM Electronics (DME), which are required to be highly efficient so-as to operate within practical budgetary constraints. This thesis develops a DME reference design based on the requirements for the Thirty Meter Telescope's next generation AO system, the Narrow Field Infrared Adaptive Optics System (NFIRAOS), which operates two DMs with a total of 7673 piezoelectric actuators. The basis of the DME is the DM actuator driver, which has been developed to be suitable for very high order reproduction by optimization of its size, power, cost and reliability. A complication is that the piezoelectric actuators in NFIRAOS DMs require high voltage drive signals of ?400 V to obtain the rated stroke and must be current limited to avoid damage. Candidate amplifiers are evaluated in simulation and hardware based on a combination of performance, physical and functional criteria; with the most suitable circuit chosen for a multi-channel prototype implementation and testing with a DM breadboard prototype. The development and optimization of an amplifier capable of meeting NFIRAOS performance criteria and budgetary constraints is demonstrated.
