Download or read book MEMS Actuated Deformable Mirror written by C. Walton and published by . This book was released on 2005 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: This ongoing work concerns the creation of a deformable mirror by the integration of MEMS actuators with Nanolaminate foils through metal compression boning. These mirrors will use the advantages of these disparate technologies to achieve dense actuation of a high-quality, continuous mirror surface. They will enable advanced adaptive optics systems in large terrestrial telescopes. While MEMS actuators provide very dense actuation with high precision they can not provide large forces typically necessary to deform conventional mirror surfaces. Nanolaminate foils can be fabricated with very high surface quality while their extraordinary mechanical properties enable very thin, flexible foils to survive the rigors of fabrication. Precise metal compression bonding allows the attachment of the fragile MEMS actuators to the thin nanolaminate foils without creating distortions at the bond sites. This paper will describe work in four major areas: (1) modeling and design, (2) bonding development, (3) nanolaminate foil development, (4) producing a prototype. A first-principles analytical model was created and used to determine the design parameters. A method of bonding was determined that is both strong, and minimizes the localized deformation or print through. Work has also been done to produce nanolaminate foils that are sufficiently thin, flexible and flat to be deformed by the MEMS actuators. Finally a prototype was produced by bonding thin, flexible nanolaminate foils to commercially available MEMS actuators.

Download or read book High Actuator Count MEMS Deformable Mirrors for Space Telescopes written by and published by . This book was released on 2010 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Micro Electro Mechanical Systems (MEMS) deformable mirrors are capable of correcting aberrations in space-based optical imaging systems. The small size, weight, and power requirements are ideal for space based adaptive optics. However, the yield, number of actuators, and surface accuracies can be improved. Yield is the proportion of the mirror segments that work. A low-power driver is also needed. The impact of microscopic manufacturing defects and substrate bowing were investigated. To reduce power consumption in the drive electronics, a multiplexed driver was investigated. A prototype of the multiplexed driver was constructed and will be used for future tests on a deformable mirror.

Download or read book MEMS Mirrors written by Huikai Xie and published by MDPI. This book was released on 2018-05-04 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "MEMS Mirrors" that was published in Micromachines

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 Fabrication Processes for MEMS Deformable Mirrors in the Next Generation Telescope Instruments written by Alioune Diouf and published by . This book was released on 2010 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: This dissertation advances three critical technology areas at the frontier of research for micro electro-mechanical systems (MEMS) deformable minors (DMs) needed for next generation telescopes (NGTs). High actuator-count MEMS deformable minors are needed for future ground-based large astronomical telescopes. Scaling up the current MEMS DMs to unprecedented numbers of independent actuators--up to 10,000 on a single DM--will require new electrical connection architecture for the actuators in order to replace the wire-bonded scheme that has been used to date. A through-wafer via interconnection fabrication process for MEMS DMs is developed to offer a path to transform the frontier of high actuator count MEMS micromirrors. In a class of NGTs instrument known as the Multi-Object Adaptive Optics (MOAO), the correction made by the DM of the wavefront phase error over the entire telescope field view is not accessible to the sensing unit. To achieve compensation, precise, single step "open-loop" commands must be developed for the DM. Due to the nonlinear relationship between applied voltage and actuation displacement at each actuator, and the mechanical coupling among actuators through the mirror membrane, such open-loop control is a formidable task. A combination of mirror surface modeling and sparse actuator empirical calibration is used to demonstrate open-loop control of MEMS deformable minors to the accuracy of closed-loop control over the entire available DM stroke. Shapes at the limit of achievable minor spatial frequencies with up to 2.5um amplitudes have been achieved within 20nm RMS error accuracy of closed-loop control. The calibration of a single actuator to be used for predicting shapes results in an additional 14nm RMS surface error compared to parallel calibration of all actuators in the deformable minor. The ubiquitous reflective coatings for MEMS deformable minors are gold and aluminum. Emerging adaptive optics application require broadband optical coatings usable from the near visible to near infrared, i.e. silver. Many of the reflective coatings of interest have high stress resulting in added curvature on deformable mirror. A thick epitaxial polysilicon MEMS mirror that can tolerate thicker reflective coatings with higher stresses has been fabricated. A thin film deposition process to counteract the stress in the reflective coating was also developed. The deformable mirror has low stress (-10 nm flatness), high reflectivity (>95%), 1024 actuated segments, that is usable over a wavelength range from visible to IR with a protective layer for the silver coating and stress-reducing layer between the silver and mirror layer to obtain the desired flatness.

Download or read book Foundry Microfabrication of Deformable Mirrors for Adaptive Optics written by William D. Cowan and published by . This book was released on 1998-04-01 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microelectromechanical Systems (MEMS) is a rapidly emerging field of research in which batch fabrication processes are used to construct miniature devices. MEMS devices are particularly well suited to optical applications. Foundry microfabrication offers a substantial cost advantage for prototype system development. In this research, foundry MEMS processes are used to fabricate low-cost deformable mirror systems (MEM-DMs) for adaptive optics. The challenges and design trades associated with fabrication of continuous and segmented deformable mirrors in foundry processes are examined in detail. Micromirror surface figure is shown to be critically important. Beam steering and optical aberration correction experiments conclusively demonstrate the potential of low-cost MEM-DMs. The prototype MEM-DM systems are approximately 1/ 500th the cost of conventionally manufactured deformable mirrors. An innovative direct digital control scheme further reduces adaptive optic system cost by eliminating the digital to analog converter typically required for each controlled element. In addition to the MEM-DMs, other MEMS devices are shown. The thermally actuated piston micromirrors offer greater deflections for operation at longer optical wavelengths. Other MEMS devices examined include a series of tilting mirrors, pressure gauges, test structures, electrostatic scratch drive actuated rotors, and a new type of electrostatic cantilever motor with lateral motion output.

Download or read book Large stroke Deformable MEMS Mirror for Focus Control written by Seyyed Mohammad Javad Moghimi and published by . This book was released on 2013 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: We developed a novel large-stroke deformable mirror for focus control and spherical aberration correction. The mirrors fabricated using MEMS technology provide full range (150-200 microns in tissue) of focus scanning at high numerical aperture (N.A.=0.5-0.7) for confocal microscopy and optical coherence tomography (OCT). In addition to large stroke, low power consumption and high speed operation are other key factors of the developed devices. The impact of this project is broad since the miniaturized deformable mirrors have a wide range of applications. In addition to focus scanning in microscopes they can also be used in small form factor systems such as cell phone cameras and robot vision. Furthermore, laser based microscopes equipped with the focus control mirror may be useful for skin cancer diagnosis and treatment. This thesis consists of seven chapters. The first chapter introduces optical focus control and focus control elements. The second chapter describes different schemes for optical focus control in imaging systems including transmissive variable lenses. The principle of operation, fabrication, and characterization of electrostatic deformable mirrors are reviewed in Chapter 3. High-speed focus control mirrors with controlled air damping are discussed in Chapter 4. In this chapter a model adopted from the analysis of MEMS microphone is used to design the backplate of a MEMS deformable mirror. Moreover, electrostatic-pneumatic MEMS deformable mirrors are introduced in Chapter 5. Analytical model is developed for electrostatic-pneumatic actuation in order to design a MEMS mirror with two membranes. Applications of MEMS deformable mirrors are demonstrated in optical systems in Chapter 6. Finally, a summary and future work are discussed in Chapter 7. The fabrication process details are given in Appendix A.

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 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 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 Optical Modeling and Validation for the Deformable Mirror Demonstration Mission written by Rachel E. Morgan (S.M.) and published by . This book was released on 2020 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microelectromechanical Systems (MEMS) Deformable Mirrors (DMs) are a promising technology to enable the wavefront control required for high contrast imaging and characterization of exoplanets with coronagraph instruments. MEMS DMs are a key technology option for future exoplanet imaging space telescopes because they can provide precise wavefront control with low size, weight, and power required. The Deformable Mirror Demonstration Mission (DeMi) CubeSat mission will demonstrate MEMS DMs in the space environment for the first time. The DeMi payload will characterize the on-orbit performance of a 140 actuator MEMS DM with 5.5 [mu]m maximum stroke, with a goal of measuring individual actuator wavefront displacement contributions to a precision of 12 nm. The payload will be able to measure low order aberrations to [lambda]/10 accuracy and [lambda]/50 precision, and will correct static and dynamic wavefront phase errors to less than 100 nm RMS. The DeMi payload contains both a Shack Hartmann wavefront sensor and an image plane wavefront sensor to monitor the DM behavior on orbit. In this thesis, an optical diffraction model is developed to simulate the signals on both the Shack Hartmann wavefront sensor and the image plane wavefront sensor. The flight payload alignment and integration process is described, and the optical model is validated with relevant data from the flight payload. The DeMi satellite is expected to launch in February 2020.

Download or read book Design Fabrication and Characterization of High stroke High aspect Ratio Micro Electro Mechanical Systems Deformable Mirrors for Adaptive Optics written by Bautista Fernández Rocha and published by . This book was released on 2011 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 On orbit Characterization of a Microelectromechanical Systems MEMS Deformable Mirror DM written by Sophia Kay Vlahakis and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The DM performed consistently and accurately throughout its lifetime with no evidence of actuators becoming stuck or unresponsive. The DeMi mission results have raised the Technology Readiness Level (TRL) of MEMS DM technology from a 5 to a 9.

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 Modulation of Electrostatic Microelectromechanical Mirrors Using a CMOS Controller written by Paul Rounsavall and published by . This book was released on 1999-03-01 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microelectromechanical Systems (MEMS) is a rapidly growing technology that lends itself particularly well to optical applications. An example of an optical MEMS device is the piston-action mirror that modulates the phase of reflected light. The phase of reflected light can be varied using thermal or electrostatic actuation to control the position of the mirror. In previous research, a modulation method to control thermally actuated mirrors was developed. This thesis presents the development, implementation, fabrication, and testing of a complimentary metal oxide semiconductor (CMOS) controller capable of directly interfacing between a digital system, such as a computer, and an electrostatically actuated MEMS mirror device. The controller pulse width modulates a supply voltage to vary the power applied to the MEMS mirror device. The MEMS mirror device responds with negligible position ripple to the applied average power of the pulse width modulation signal. By varying the duty cycle of the pulse width modulation signal, the position of the mirror is varied. This controller can be adapted to control other electrostatically actuated devices using the design and methodology described in this thesis. The implementation of this controller is a step toward the monolithic integration of a MEMS deformable mirror array with CMOS control electronics.

Download or read book Integrated MEMS Technologies for Adaptive Optics written by Blake Ching-Yu Lin and published by . This book was released on 2008 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: