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Sample records for micro-electro-mechanical deformable mirrors

  1. Characterization Of High-Stroke High-Aspect Ratio Micro Electro Mechanical Systems Deformable Mirrors For Adaptive Optics

    NASA Astrophysics Data System (ADS)

    Bouchti, Mohamed Amine

    Adaptive optics MEMS deformable mirror, in conjunction with Shack Hartman wave front sensor and real-time controller, is capable of correcting time-varying aberrations in imaging applications through manipulating its mirror surface. Adaptive optics systems in astronomy for next generation large telescopes (30 meter primary mirrors) require a high stroke of 10microm of mechanical displacement. This required stroke would be achieved by MEMS deformable mirrors fabricated with high aspect ratio techniques. This thesis will review the designs of various types of high aspect actuators consisting of folded springs with rectangular and circular membranes as well as X-beam actuators. Finite element analysis (FEA) simulations of these designs have shown the ability of each design to achieve a stroke of approximately 9.4 microm. Also, FEA simulations proved that the X-beam actuators provide the best spring support while preventing tilting. In addition, this thesis will discuss device characterization and voltage vs. displacement test results for the high aspect ratio gold MEMS 16 x 16 X-beam actuators deformable mirror that has been bonded and packaged. The results have shown that the device is capable of achieving approximately 5.5 microm in individual actuator testing and 7microm in dual actuator testing.

  2. Design, fabrication and characterization of high-stroke high-aspect ratio micro electro mechanical systems deformable mirrors for adaptive optics

    NASA Astrophysics Data System (ADS)

    Fernandez Rocha, Bautista

    Adaptive optic (AO) systems for next generation of extremely large telescopes (30--50 meter diameter primary mirrors) require high-stroke (10 microns), high-order (100x100) deformable mirrors at lower-cost than current technology. The required specifications are achievable with Micro Electro Mechanical Systems (MEMS) devices fabricated with high-aspect ratio processing techniques. This dissertation will review simulation results compared with displacement measurements of actuators utilizing a white-light interferometer. It will also review different actuator designs, materials and post-processing procedures fabricated in three different high-aspect ratio processes, Microfabrica's Electrochemical Fabrication (EFAB(TM)), HT-Micro's Precision Fabrication Technology (HTPF(TM)), and Innovative Micro Technologies (IMT) fabrication process. These manufacturing processes allow high-precision multilayer fabrication and their sacrificial layer thicknesses can be specified by the designer, rather than by constraints of the fabrication process. Various types of high-stroke gold actuators for AO consisting of folded springs with rectangular and circular membranes as well as X-beam actuators supported diagonally by beams were designed, simulated, fabricated, and tested individually and as part of a continuous facesheet DM system. The design, modeling and simulation of these actuators are compared to experimental measurements of their pull-in voltages, which characterizes their stiffness and maximum stroke. Vertical parallel plate ganged actuators fabricated with the EFAB(TM) process have a calculated pull-in voltage of 95V for a 600mum size device. In contrast, the pull-in voltages for the comb-drive actuators ranged from 55V for the large actuator, to 203V for the smallest actuator. Simulations and interferometer scans of actuator designs fabricated with HT-Micro's Precision Fabrication (HTPF(TM)) two wafer bonded process with different spring supports have shown the ability of

  3. An Investigation into the Response of a Micro Electro Mechanical Compound Pivot Mirror Using Finite Element Modeling

    SciTech Connect

    GASS, FAWN R.; DOHNER, JEFFREY L.

    2002-01-01

    This report is a presentation of modeling and simulation work for analyzing three designs of Micro Electro Mechanical (MEM) Compound Pivot Mirrors (CPM). These CPMs were made at Sandia National Laboratories using the SUMMiT{trademark} process. At 75 volts and above, initial experimental analysis of fabricated mirrors showed tilt angles of up to 7.5 degrees for one design, and 5 degrees for the other two. Nevertheless, geometric design models predicted higher tilt angles. Therefore, a detailed study was conducted to explain why lower tilt angles occurred and if design modifications could be made to produce higher tilt angles at lower voltages. This study showed that the spring stiffnesses of the CPMs were too great to allow for desired levels of rotation at lower levels of voltage. To produce these lower stiffnesses, a redesign is needed.

  4. Micro electro mechanical system optical switching

    SciTech Connect

    Thorson, Kevin J; Stevens, Rick C; Kryzak, Charles J; Leininger, Brian S; Kornrumpf, William P; Forman, Glenn A; Iannotti, Joseph A; Spahn, Olga B; Cowan, William D; Dagel, Daryl J

    2013-12-17

    The present disclosure includes apparatus, system, and method embodiments that provide micro electo mechanical system optical switching and methods of manufacturing switches. For example, one optical switch embodiment includes at least one micro electro mechanical system type pivot mirror structure disposed along a path of an optical signal, the structure having a mirror and an actuator, and the mirror having a pivot axis along a first edge and having a second edge rotatable with respect to the pivot axis, the mirror being capable of and arranged to be actuated to pivot betweeen a position parallel to a plane of an optical signal and a position substantially normal to the plane of the optical signal.

  5. Monitoring of slope-instabilities and deformations with Micro-Electro-Mechanical-Systems (MEMS) in wireless ad-hoc Sensor Networks

    NASA Astrophysics Data System (ADS)

    Arnhardt, C.; Fernández-Steeger, T. M.; Azzam, R.

    2009-04-01

    In most mountainous regions, landslides represent a major threat to human life, properties and infrastructures. Nowadays existing landslide monitoring systems are often characterized by high efforts in terms of purchase, installation, maintenance, manpower and material. In addition (or because of this) only small areas or selective points of the endangered zone can be observed by the system. Therefore the improvement of existing and the development of new monitoring and warning systems are of high relevance. The joint project "Sensor based Landslide Early Warning Systems" (SLEWS) deals with the development of a prototypic Alarm- and Early Warning system (EWS) for different types of landslides using low-cost micro-sensors (MEMS) integrated in a wireless sensor network (WSN). Modern so called Ad-Hoc, Multi-Hop wireless sensor networks (WSN) are characterized by a self organizing and self-healing capacity of the system (autonomous systems). The network consists of numerous individual and own energy-supply operating sensor nodes, that can send data packages from their measuring devices (here: MEMS) over other nodes (Multi-Hop) to a collection point (gateway). The gateway provides the interface to central processing and data retrieval units (PC, Laptop or server) outside the network. In order to detect and monitor the different landslide processes (like fall, topple, spreading or sliding) 3D MEMS capacitive sensors made from single silicon crystals and glass were chosen to measure acceleration, tilting and altitude changes. Based on the so called MEMS (Micro-Electro-Mechanical Systems) technology, the sensors combine very small mechanical and electronic units, sensing elements and transducers on a small microchip. The mass production of such type of sensors allows low cost applications in different areas (like automobile industries, medicine, and automation technology). Apart from the small and so space saving size and the low costs another advantage is the energy

  6. Monitoring of slope-instabilities and deformations with Micro-Electro-Mechanical-Systems (MEMS) in wireless ad-hoc Sensor Networks

    NASA Astrophysics Data System (ADS)

    Arnhardt, C.; Fernández-Steeger, T. M.; Azzam, R.

    2009-04-01

    In most mountainous regions, landslides represent a major threat to human life, properties and infrastructures. Nowadays existing landslide monitoring systems are often characterized by high efforts in terms of purchase, installation, maintenance, manpower and material. In addition (or because of this) only small areas or selective points of the endangered zone can be observed by the system. Therefore the improvement of existing and the development of new monitoring and warning systems are of high relevance. The joint project "Sensor based Landslide Early Warning Systems" (SLEWS) deals with the development of a prototypic Alarm- and Early Warning system (EWS) for different types of landslides using low-cost micro-sensors (MEMS) integrated in a wireless sensor network (WSN). Modern so called Ad-Hoc, Multi-Hop wireless sensor networks (WSN) are characterized by a self organizing and self-healing capacity of the system (autonomous systems). The network consists of numerous individual and own energy-supply operating sensor nodes, that can send data packages from their measuring devices (here: MEMS) over other nodes (Multi-Hop) to a collection point (gateway). The gateway provides the interface to central processing and data retrieval units (PC, Laptop or server) outside the network. In order to detect and monitor the different landslide processes (like fall, topple, spreading or sliding) 3D MEMS capacitive sensors made from single silicon crystals and glass were chosen to measure acceleration, tilting and altitude changes. Based on the so called MEMS (Micro-Electro-Mechanical Systems) technology, the sensors combine very small mechanical and electronic units, sensing elements and transducers on a small microchip. The mass production of such type of sensors allows low cost applications in different areas (like automobile industries, medicine, and automation technology). Apart from the small and so space saving size and the low costs another advantage is the energy

  7. Micro Electro-Mechanical System (MEMS) Pressure Sensor for Footwear

    DOEpatents

    Kholwadwala, Deepesh K.; Rohrer, Brandon R.; Spletzer, Barry L.; Galambos, Paul C.; Wheeler, Jason W.; Hobart, Clinton G.; Givler, Richard C.

    2008-09-23

    Footwear comprises a sole and a plurality of sealed cavities contained within the sole. The sealed cavities can be incorporated as deformable containers within an elastic medium, comprising the sole. A plurality of micro electro-mechanical system (MEMS) pressure sensors are respectively contained within the sealed cavity plurality, and can be adapted to measure static and dynamic pressure within each of the sealed cavities. The pressure measurements can provide information relating to the contact pressure distribution between the sole of the footwear and the wearer's environment.

  8. Integrated micro-electro-mechanical sensor development for inertial applications

    SciTech Connect

    Allen, J.J.; Kinney, R.D.; Sarsfield, J.

    1998-04-01

    Electronic sensing circuitry and micro electro mechanical sense elements can be integrated to produce inertial instruments for applications unheard of a few years ago. This paper will describe the Sandia M3EMS fabrication process, inertial instruments that have been fabricated, and the results of initial characterization tests of micro-machined accelerometers.

  9. Micro-electro-mechanically switchable near infrared complementary metamaterial absorber

    SciTech Connect

    Pitchappa, Prakash; Pei Ho, Chong; Kropelnicki, Piotr; Singh, Navab; Kwong, Dim-Lee; Lee, Chengkuo

    2014-05-19

    We experimentally demonstrate a micro-electro-mechanically switchable near infrared complementary metamaterial absorber by integrating the metamaterial layer to be the out of plane movable microactuator. The metamaterial layer is electrostatically actuated by applying voltage across the suspended complementary metamaterial layer and the stationary bottom metallic reflector. Thus, the effective spacing between the metamaterial layer and bottom metal reflector is varied as a function of applied voltage. With the reduction of effective spacing between the metamaterial and reflector layers, a strong spectral blue shift in the peak absorption wavelength can be achieved. With spacing change of 300 nm, the spectral shift of 0.7 μm in peak absorption wavelength was obtained for near infrared spectral region. The electro-optic switching performance of the device was characterized, and a striking switching contrast of 1500% was achieved at 2.1 μm. The reported micro-electro-mechanically tunable complementary metamaterial absorber device can potentially enable a wide range of high performance electro-optical devices, such as continuously tunable filters, modulators, and electro-optic switches that form the key components to facilitate future photonic circuit applications.

  10. Micro-electro-mechanically tunable metamaterial with enhanced electro-optic performance

    SciTech Connect

    Pitchappa, Prakash; Pei Ho, Chong; Lin, Yu-Sheng; Lee, Chengkuo; Kropelnicki, Piotr; Singh, Navab; Huang, Chia-Yi

    2014-04-14

    We experimentally demonstrate a micro-electro-mechanically tunable metamaterial with enhanced electro-optical performance by increasing the number of movable cantilevers in the symmetrical split ring resonator metamaterial unit cell. Simulations were carried out to understand the interaction of the incident terahertz radiation with out-of-plane deforming metamaterial resonator. In order to improve the overall device performance, the number of released cantilever in a unit cell was increased from one to two, and it was seen that the tunable range was doubled and the switching contrast improved by a factor of around five at 0.7 THz. This simple design approach can be adopted for a wide range of high performance electro-optical devices such as continuously tunable filters, modulators, and electro-optic switches to enable future photonic circuit applications.

  11. Controlling Micro ElectroMechanical Systems (MEMS) in Space

    NASA Astrophysics Data System (ADS)

    Farrar, D.; Schneider, W.; Osiander, R.; Champion, J. L.; Darrin, A. G.; Douglas, D.; Swanson, T. D.

    2003-01-01

    Small spacecraft, including micro and nanosats, as they are envisioned for future missions, will require an alternative means to achieve thermal control due to their small power and mass budgets. One of the proposed alternatives is Variable Emittance (Vari-E) Coatings for spacecraft radiators. Space Technology-5 (ST-5) is a technology demonstration mission through NASA Goddard Space Flight Center (GSFC) that will utilize Vari-E Coatings. This mission involves a constellation of three (3) satellites in a highly elliptical orbit with a perigee altitude of ~200 km and an apogee of ~38,000 km. Such an environment will expose the spacecraft to a wide swing in the thermal and radiation environment of the earth's atmosphere. There are three (3) different technologies associated with this mission. The three technologies are electrophoretic, electrochromic, and Micro ElectroMechanical Systems (MEMS). The ultimate goal is to make use of Vari-E coatings, in order to achieve various levels of thermal control. The focus of this paper is to highlight the Vari-E Coating MEMS instrument, with an emphasis on the Electronic Control Unit responsible for operating the MEMS device. The Test & Evaluation approach, along with the results, is specific for application on ST-5, yet the information provides a guideline for future experiments and/or thermal applications on the exterior structure of a spacecraft.

  12. Initial performance results for high-aspect ratio gold MEMS deformable mirrors

    NASA Astrophysics Data System (ADS)

    Fernández, Bautista; Kubby, Joel

    2009-02-01

    The fabrication and initial performance results of high-aspect ratio 3-dimensional Micro-Electro-Mechanical System (MEMS) Deformable Mirrors (DM) for Adaptive Optics (AO) will be discussed. The DM systems were fabricated out of gold, and consist of actuators bonded to a continuous face sheet, with different boundary conditions. DM mirror displacements vs. voltage have been measured with a white light interferometer and the corresponding results compared to Finite Element Analysis (FEA) simulations. Interferometer scans of a DM have shown that ~9.4um of stroke can be achieved with low voltage, thus showing that this fabrication process holds promise in the manufacturing of future MEMS DM's for the next generation of extremely large telescopes.

  13. Nanolaminate deformable mirrors

    DOEpatents

    Papavasiliou, Alexandros P.; Olivier, Scot S.

    2009-04-14

    A deformable mirror formed out of two layers of a nanolaminate foil attached to a stiff substrate is introduced. Deformation is provided by an electrostatic force between two of the layers. The internal stiffness of the structure allows for high-spatial-frequency shapes. The nanolaminate foil of the present invention allows for a high-quality mirror surface. The device achieves high precision in the vertical direction by using foils with accurately controlled thicknesses, but does not require high precision in the lateral dimensions, allowing such mirrors to be fabricated using crude lithography techniques. Such techniques allow structures up to about the meter scale to be fabricated.

  14. Nanolaminate deformable mirrors

    DOEpatents

    Papavasiliou, Alexandros P.; Olivier, Scot S.

    2010-04-06

    A deformable mirror formed out of two layers of a nanolaminate foil attached to a stiff substrate is introduced. Deformation is provided by an electrostatic force between two of the layers. The internal stiffness of the structure allows for high-spatial-frequency shapes. The nanolaminate foil of the present invention allows for a high-quality mirror surface. The device achieves high precision in the vertical direction by using foils with accurately controlled thicknesses, but does not require high precision in the lateral dimensions, allowing such mirrors to be fabricated using crude lithography techniques. Such techniques allow structures up to about the meter scale to be fabricated.

  15. Partially segmented deformable mirror

    DOEpatents

    Bliss, Erlan S.; Smith, James R.; Salmon, J. Thaddeus; Monjes, Julio A.

    1991-01-01

    A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp.

  16. Partially segmented deformable mirror

    DOEpatents

    Bliss, E.S.; Smith, J.R.; Salmon, J.T.; Monjes, J.A.

    1991-05-21

    A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp. 5 figures.

  17. Design and development of microswitches for micro-electro-mechanical relay matrices

    NASA Astrophysics Data System (ADS)

    Phipps, Mark W.

    1995-06-01

    Many different micro-electro-mechanical (MEM) switches were designed in the Multi-User MEM's Processes (MUMP's) and deep x-ray lithography and electroforming (LIGA) processes. The switches were composed of actuators that operated based upon either electrostatic forces or thermal forces. A thermally activated beam flexure actuator that operated based upon differential heating was used extensively. This actuator, which was fabricated in the MUMP's process, was able to deflect up to 12 microns with a total input power of less than 25 mW. The thermal resistance, which was needed to model this actuator, was determined from a material constant, 1.9 +/- 0.08 m(exp 1.5) C/W for the POLY1 layer in MUMP's and 7.4 +/- 0.88 m(exp 1.5) C/W for the POLY2 layer in MUMP's, which was extracted from 1020 actuator test cases. A switch using a hinge mechanism that allowed metal-to-metal contacts to be formed was also developed in the MUMP's process. The contact resistance of these devices was determined to be 9.91 +/- 6.22 kohms. An electrostatically deformable microbridge structure (2 microns thick, 40 microns wide, 332 microns long, and with a capacitive gap of 2 microns) was also employed as a switch. A voltage of 53.3 volts applied between the microbridge and two drive electrodes was able to force the center of the microbridge to touch a sense electrode. The observed contact resistance for this connection was 300 +/- 89.7 ohms.

  18. MEMS Actuated Deformable Mirror

    SciTech Connect

    Papavasiliou, A; Olivier, S; Barbee, T; Walton, C; Cohn, M

    2005-11-10

    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.

  19. Detection of Dynabeads using a micro-electro-mechanical-systems fluxgate sensor

    NASA Astrophysics Data System (ADS)

    Lei, Jian; Wang, Tao; Lei, Chong; Zhou, Yong

    2013-01-01

    This paper presents an approach to detect the presence of Dynabeads with a system based on a micro fluxgate sensor fabricated by micro-electro-mechanical systems technology. Due to the excellent performance of the micro fluxgate sensor, the detection system exhibited many advantages, such as lower minimum detectable limit, small weight, and low power consumption. Experimental results show that, applied an external magnetic field in a range of 430 μT to 600 μT, Dynabeads with a concentration as low as 0.1 μg/ml can be detected by this system. Moreover, the detection system could give an approximate quantitation to the magnetic beads.

  20. Characteristics of semiconductor bridge (SCB) plasma generated in a micro-electro-mechanical system (MEMS)

    NASA Astrophysics Data System (ADS)

    Kim, Jong-Uk; Park, Chong-Ook; Park, Myung-Il; Kim, Sun-Hwan; Lee, Jung-Bok

    2002-12-01

    Plasma ignition method has been applied in various fields particularly to the rocket propulsion, pyrotechnics, explosives, and to the automotive air-bag system. Ignition method for those applications should be safe and also operate reliably in hostile environments such as; electromagnetic noise, drift voltage, electrostatic background and so on. In the present Letter, a semiconductor bridge (SCB) plasma ignition device was fabricated and its plasma characteristics including the propagation speed of the plasma, plasma size, and plasma temperature were investigated with the aid of the visualization of micro scale plasma (i.e., ⩽350 μm), which generated from a micro-electro-mechanical poly-silicon semiconductor bridge (SCB).

  1. Stroke amplifier for deformable mirrors

    PubMed Central

    Webb, Robert H.; Albanese, Marc J.; Zhou, Yaopeng; Bifano, Thomas; Burns, Stephen A.

    2010-01-01

    We demonstrate a simple optical configuration that amplifies the usable stroke of a deformable mirror. By arranging for the wavefront to traverse the deformable mirror more than once, we correct it more than once. The experimental implementation of the idea demonstrates a doubling of 2.0 and 2.04 by two different means. PMID:15495423

  2. Variable focal length deformable mirror

    DOEpatents

    Headley, Daniel; Ramsey, Marc; Schwarz, Jens

    2007-06-12

    A variable focal length deformable mirror has an inner ring and an outer ring that simply support and push axially on opposite sides of a mirror plate. The resulting variable clamping force deforms the mirror plate to provide a parabolic mirror shape. The rings are parallel planar sections of a single paraboloid and can provide an on-axis focus, if the rings are circular, or an off-axis focus, if the rings are elliptical. The focal length of the deformable mirror can be varied by changing the variable clamping force. The deformable mirror can generally be used in any application requiring the focusing or defocusing of light, including with both coherent and incoherent light sources.

  3. A Micro Electrical Mechanical Systems (MEMS)-based Cryogenic Deformable Mirror

    NASA Astrophysics Data System (ADS)

    Enya, K.; Kataza, H.; Bierden, P.

    2009-03-01

    We present our first results on the development and evaluation of a cryogenic deformable mirror (DM) based on Micro Electro Mechanical Systems (MEMS) technology. A MEMS silicon-based DM chip with 32 channels, in which each channel is 300 μm × 300 μm in size, was mounted on a silicon substrate in order to minimize distortion and prevent it from being permanently damaged by thermal stresses introduced by cooling. The silicon substrate was oxidized to obtain electric insulation and had a metal fan-out pattern on the surface. For cryogenic tests, we constructed a measurement system consisting of a Fizeau interferometer, a cryostat cooled by liquid N2, zooming optics, electric drivers. The surface of the mirror at 95 K deformed in response to the application of a voltage, and no significant difference was found between the deformation at 95 K and that at room temperature. The power dissipation by the cryogenic DM was also measured, and we suggest that this is small enough for it to be used in a space cryogenic telescope. The properties of the DM remained unchanged after five cycles of vacuum pumping, cooling, warming, and venting. We conclude that fabricating cryogenic DMs employing MEMS technology is a promising approach. Therefore, we intend to develop a more sophisticated device for actual use, and to look for potential applications including the Space Infrared Telescope for Cosmology & Astrophysics (SPICA), and other missions.

  4. Hybrid Micro-Electro-Mechanical Systems for Highly Reliable and Selective Characterization of Tank Waste

    SciTech Connect

    Panos G. Datskos; Michael J. Sepaniak; Nickolay Lavrik; Pampa Dutta; Mustafa Culha

    2005-12-28

    The main objective of this research program is to develop robust and reliable micro-electro-mechanical sensing systems, based on microcantilevers (MCs), that can operate in liquid environments with high levels of sensitivity and selectivity. The chemical responses of MCs result from analyte-induced differential stress at the cantilever surfaces. We aim to employ various surface nanostructuring strategies that enhance these stresses and hence the degree of static bending of the cantilevers. Receptor phases as self assembled monolayers (SAMs) and thin films are being synthesized and tested to provide selectivity. Selectivity is chemically enhanced by using different phases on individual MCs in arrays and by adding a spectroscopic component, surface enhanced Raman spectrometry (SERS), in hybrid approaches to sensing. Significant progress was made in tasks that were listed in the work plan for DOE EMSP project ''Hybrid Micro-Electro-Mechanical Systems for Highly Reliable and Selective Characterization of Tank Waste''. Several project areas are listed below and discussed and referenced to our literature on the topics.

  5. Development and control of kilo-pixel MEMS deformable mirrors and spatial light modulators

    NASA Astrophysics Data System (ADS)

    Perreault, Julie Ann

    This dissertation describes the development of kilo-pixel micro-electro-mechanical optical-quality surface-micromachined deformable mirrors and spatial light modulators along with scalable control electronics. These silicon-based deformable mirrors have the potential to modulate spatial and temporal features of an optical wavefront with applications in imaging, beam-forming, and optical communication systems. Techniques to improve the manufacturing, quality, and capability of these mirrors are detailed. The new mirror system was characterized and a scalable control system was developed to coordinate and control a large array of mirrors. Three types of kilo-pixel deformable mirrors were created: continuous membrane, segmented membrane, and a hybrid stress-relieved membrane mirrors. This new class of mirrors, deformed using electrostatically actuated surface-normal actuators, have an aperature of 10 mm, a stroke of 2 mum, position repeatability of 3 nm, surface roughness of 12 nm, reflectivity of 91%, and a bandwidth in air of 7 kHz. A custom fabrication process was developed in tandem with a new mirror design to address design and layout issues including packaging, residual stress, reliability, yield, fill factor, and surface topography. A chemo-mechanical polishing process improved the surface quality of the mirrors by decreasing surface roughness from an RMS value of 46nm to 12nm. A gold coating process increased reflectivity from 42% to greater than 91% without introducing a significant amount of stress in the mirror membrane. An alternative actuator design and layout was also developed that achieved an increased stroke of 6 mum, with the potential for even longer stroke with stress reduction. The long stroke capability was realized through introduction of split electrodes, actuation membrane cuts, and a double stacked anchor architecture. A computer-driven electronic system was developed to aid in the electro-mechanical testing of these deformable mirrors. Quasi

  6. Multiple internal seal ring micro-electro-mechanical system vacuum packaging method

    NASA Technical Reports Server (NTRS)

    Hayworth, Ken J. (Inventor); Yee, Karl Y. (Inventor); Shcheglov, Kirill V. (Inventor); Bae, Youngsam (Inventor); Wiberg, Dean V. (Inventor); Challoner, A. Dorian (Inventor); Peay, Chris S. (Inventor)

    2008-01-01

    A Multiple Internal Seal Ring (MISR) Micro-Electro-Mechanical System (MEMS) vacuum packaging method that hermetically seals MEMS devices using MISR. The method bonds a capping plate having metal seal rings to a base plate having metal seal rings by wafer bonding the capping plate wafer to the base plate wafer. Bulk electrodes may be used to provide conductive paths between the seal rings on the base plate and the capping plate. All seals are made using only metal-to-metal seal rings deposited on the polished surfaces of the base plate and capping plate wafers. However, multiple electrical feed-through metal traces are provided by fabricating via holes through the capping plate for electrical connection from the outside of the package through the via-holes to the inside of the package. Each metal seal ring serves the dual purposes of hermetic sealing and providing the electrical feed-through metal trace.

  7. Application of Micro-Electro-Mechanical Sensors Contactless NDT of Concrete Structures

    PubMed Central

    Ham, Suyun; Popovics, John S.

    2015-01-01

    The utility of micro-electro-mechanical sensors (MEMS) for application in air-coupled (contactless or noncontact) sensing to concrete nondestructive testing (NDT) is studied in this paper. The fundamental operation and characteristics of MEMS are first described. Then application of MEMS sensors toward established concrete test methods, including vibration resonance, impact-echo, ultrasonic surface wave, and multi-channel analysis of surface waves (MASW), is demonstrated. In each test application, the performance of MEMS is compared with conventional contactless and contact sensing technology. Favorable performance of the MEMS sensors demonstrates the potential of the technology for applied contactless NDT efforts. Objective: To illustrate the utility of air-coupled MEMS sensors for concrete NDT, as compared with conventional sensor technology. PMID:25897497

  8. Effect of materials for micro-electro-mechanical systems on PCR yield.

    PubMed

    Potrich, Cristina; Lunelli, Lorenzo; Forti, Stefania; Vozzi, Diego; Pasquardini, Laura; Vanzetti, Lia; Panciatichi, Cristina; Anderle, Mariano; Pederzolli, Cecilia

    2010-05-01

    In this study we analyzed the surface properties of different silicon-based materials used for micro-electro-mechanical systems (MEMS) production, such as thermally grown silicon oxide, plasma-enhanced chemical vapor deposition (PECVD)-treated silicon oxide, reactive-ion etch (RIE)-treated silicon oxide, and Pyrex. Substrates were characterized by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) to define the surface chemical and morphological properties, and by fluorescence microscopy to directly assess the absorption of the different polymerase chain reaction (PCR) components. By using microchips fabricated with the same materials we investigated their compatibility with PCR reactions, exploiting the use of different enzymes and reagents or proper surface treatments. We established the best conditions for DNA amplification in silicon/Pyrex microdevices depending on the type of device and fabrication method used and the quality of reagents, rather than on the passivation treatment or increment in standard Taq polymerase concentration. PMID:19455320

  9. Micro-Electro-Mechanical-Systems-Based Micro-Ro-Boat Utilizing Steam as Propulsion Power

    NASA Astrophysics Data System (ADS)

    Choi, Ju Chan; Choi, Young Chan; Kyoo Lee, June; Kong, Seong Ho

    2012-06-01

    We report the design and fabrication of a micro-electro-mechanical-systems (MEMS)-based microactuator, that floats on the surface of water and is driven by steam. We named the actuator “micro-Ro-boat”, a compound word created from the words “robot” and “boat”. The MEMS-based micro-Ro-boat utilizes steam as the propulsion power, giving it a high speed and long lifetime. A hydrophobic surface has been utilized for the wing of the actuator to enhance the buoyancy. Instead of using gas or fuel, the proposed micro-Ro-boat utilizes steam form electrically heated water. The velocity of the micro-Ro-boat is in the range of 0.5-2 cm/s and the maximum loading capability for a device size of 10 ×10 mm2 is 0.4 g.

  10. Multiple internal seal right micro-electro-mechanical system vacuum package

    NASA Technical Reports Server (NTRS)

    Hayworth, Ken J. (Inventor); Yee, Karl Y. (Inventor); Shcheglov, Kirill V. (Inventor); Bae, Youngsam (Inventor); Wiberg, Dean V. (Inventor); Challoner, A. Dorian (Inventor); Peay, Chris S. (Inventor)

    2007-01-01

    A Multiple Internal Seal Ring (MISR) Micro-Electro-Mechanical System (MEMS) vacuum package that hermetically seals MEMS devices using MISR. The method bonds a capping plate having metal seal rings to a base plate having metal seal rings by wafer bonding the capping plate wafer to the base plate wafer. Bulk electrodes may be used to provide conductive paths between the seal rings on the base plate and the capping plate. All seals are made using only metal-to-metal seal rings deposited on the polished surfaces of the base plate and capping plate wafers. However, multiple electrical feed-through metal traces are provided by fabricating via holes through the capping plate for electrical connection from the outside of the package through the via-holes to the inside of the package. Each metal seal ring serves the dual purposes of hermetic sealing and providing the electrical feed-through metal trace.

  11. Diffusion Bonding of Silicon Carbide for a Micro-Electro-Mechanical Systems Lean Direct Injector

    NASA Technical Reports Server (NTRS)

    Halbig, Michael C.; Singh, Mrityunjay; Shpargel, Tarah P.; Kiser, James D.

    2006-01-01

    Robust approaches for joining silicon carbide (SiC) to silicon carbide sub-elements have been developed for a micro-electro-mechanical systems lean direct injector (MEMS LDI) application. The objective is to join SiC sub-elements to form a leak-free injector that has complex internal passages for the flow and mixing of fuel and air. Previous bonding technology relied upon silicate glass interlayers that were not uniform or leak free. In a newly developed joining approach, titanium foils and physically vapor deposited titanium coatings were used to form diffusion bonds between SiC materials during hot pressing. Microscopy results show the formation of well adhered diffusion bonds. Initial tests show that the bond strength is much higher than required for the component system. Benefits of the joining technology are fabrication of leak free joints with high temperature and mechanical capability.

  12. On-Chip Micro-Electro-Mechanical System Fourier Transform Infrared (MEMS FT-IR) Spectrometer-Based Gas Sensing.

    PubMed

    Erfan, Mazen; Sabry, Yasser M; Sakr, Mohammad; Mortada, Bassem; Medhat, Mostafa; Khalil, Diaa

    2016-05-01

    In this work, we study the detection of acetylene (C2H2), carbon dioxide (CO2) and water vapor (H2O) gases in the near-infrared (NIR) range using an on-chip silicon micro-electro-mechanical system (MEMS) Fourier transform infrared (FT-IR) spectrometer in the wavelength range 1300-2500 nm (4000-7692 cm(-1)). The spectrometer core engine is a scanning Michelson interferometer micro-fabricated using a deep-etching technology producing self-aligned components. The light is free-space propagating in-plane with respect to the silicon chip substrate. The moving mirror of the interferometer is driven by a relatively large stroke electrostatic comb-drive actuator corresponding to about 30 cm(-1) resolution. Multi-mode optical fibers are used to connect light between the wideband light source, the interferometer, the 10 cm gas cell, and the optical detector. A wide dynamic range of gas concentration down to 2000 parts per million (ppm) in only 10 cm length gas cell is demonstrated. Extending the wavelength range to the mid-infrared (MIR) range up to 4200 nm (2380 cm(-1)) is also experimentally demonstrated, for the first time, using a bulk micro-machined on-chip MEMS FT-IR spectrometer. The obtained results open the door for an on-chip optical gas sensor for many applications including environmental sensing and industrial process control in the NIR/MIR spectral ranges. PMID:27044847

  13. Large Scale Nanolaminate Deformable Mirror

    SciTech Connect

    Papavasiliou, A; Olivier, S; Barbee, T; Miles, R; Chang, K

    2005-11-30

    This work concerns the development of a technology that uses Nanolaminate foils to form light-weight, deformable mirrors that are scalable over a wide range of mirror sizes. While MEMS-based deformable mirrors and spatial light modulators have considerably reduced the cost and increased the capabilities of adaptive optic systems, there has not been a way to utilize the advantages of lithography and batch-fabrication to produce large-scale deformable mirrors. This technology is made scalable by using fabrication techniques and lithography that are not limited to the sizes of conventional MEMS devices. Like many MEMS devices, these mirrors use parallel plate electrostatic actuators. This technology replicates that functionality by suspending a horizontal piece of nanolaminate foil over an electrode by electroplated nickel posts. This actuator is attached, with another post, to another nanolaminate foil that acts as the mirror surface. Most MEMS devices are produced with integrated circuit lithography techniques that are capable of very small line widths, but are not scalable to large sizes. This technology is very tolerant of lithography errors and can use coarser, printed circuit board lithography techniques that can be scaled to very large sizes. These mirrors use small, lithographically defined actuators and thin nanolaminate foils allowing them to produce deformations over a large area while minimizing weight. This paper will describe a staged program to develop this technology. First-principles models were developed to determine design parameters. Three stages of fabrication will be described starting with a 3 x 3 device using conventional metal foils and epoxy to a 10-across all-metal device with nanolaminate mirror surfaces.

  14. Microwave Tomography Using Deformable Mirrors

    NASA Astrophysics Data System (ADS)

    Arunachalam, Kavitha; Udpa, Lalita; Udpa, Satish S.

    2008-09-01

    Microwave tomography aims to reconstruct the spatial distribution of the electrical property of penetrable objects using field measurements acquired from multiple views at single or multiple frequencies. This paper presents a novel microwave tomography technique to image penetrable scatterers using deformable mirrors. The deformable mirror consists of a continuum of radiating elements that yields multi-view field measurements for noninvasive characterization of the spatial dielectric property of the scatterer in the microwave regime. Computational feasibility of the proposed technique is presented for heterogeneous two dimensional dielectric scatterers.

  15. Controllable objective with deformable mirrors

    SciTech Connect

    Agafonov, V V; Safronov, A G

    2004-03-31

    A new optical device - an objective with deformable mirrors and parameters controlled in the dynamic regime is proposed. The computer simulation of the objective is performed. The dependences of some parameters of the objective on the control voltage are determined. The simulation showed that the ranges of control of the rear focal segment and the focal distance for the objective with the focal distance 602 mm were 1057 and 340 mm, respectively, which is substantially greater than in the control of an equivalent deformable mirror. (laser applications and other topics in quantum electronics)

  16. Experimental Identification of Smartphones Using Fingerprints of Built-In Micro-Electro Mechanical Systems (MEMS)

    PubMed Central

    Baldini, Gianmarco; Steri, Gary; Dimc, Franc; Giuliani, Raimondo; Kamnik, Roman

    2016-01-01

    The correct identification of smartphones has various applications in the field of security or the fight against counterfeiting. As the level of sophistication in counterfeit electronics increases, detection procedures must become more accurate but also not destructive for the smartphone under testing. Some components of the smartphone are more likely to reveal their authenticity even without a physical inspection, since they are characterized by hardware fingerprints detectable by simply examining the data they provide. This is the case of MEMS (Micro Electro-Mechanical Systems) components like accelerometers and gyroscopes, where tiny differences and imprecisions in the manufacturing process determine unique patterns in the data output. In this paper, we present the experimental evaluation of the identification of smartphones through their built-in MEMS components. In our study, three different phones of the same model are subject to repeatable movements (composing a repeatable scenario) using an high precision robotic arm. The measurements from MEMS for each repeatable scenario are collected and analyzed. The identification algorithm is based on the extraction of the statistical features of the collected data for each scenario. The features are used in a support vector machine (SVM) classifier to identify the smartphone. The results of the evaluation are presented for different combinations of features and Inertial Measurement Unit (IMU) outputs, which show that detection accuracy of higher than 90% is achievable. PMID:27271630

  17. Softening and Hardening of a Micro-electro-mechanical systems (MEMS) Oscillator in a Nonlinear Regime

    NASA Astrophysics Data System (ADS)

    Johnson, Sarah; Edmonds, Terrence

    Micro-electro-mechanical systems or MEMS are used in a variety of today's technology and can be modeled using equations for nonlinear damped harmonic oscillators. Mathematical expressions have been formulated to determine resonance frequency shifts as a result of hardening and softening effects in MEMS devices. In this work we experimentally test the previous theoretical analysis of MEMS resonance frequency shifts in the nonlinear regime. Devices were put under low pressure at room temperature and swept through a range of frequencies with varying AC and DC excitation voltages to detect shifts in the resonant frequency. The MEMS device studied in this work exhibits a dominating spring softening effect due to the device's physical make-up. The softening effect becomes very dominant as the AC excitation is increased and the frequency shift of the resonance peak becomes quite significant at these larger excitations. Hardening effects are heavily dependent on mechanical factors that make up the MEMS devices. But they are not present in these MEMS devices. I will present our results along with the theoretical analysis of the Duffing oscillator model. This work was supported by NSF grant DMR-1461019 (REU) and DMR-1205891 (YL).

  18. The potential of micro-electro-mechanical accelerometers in human vibration measurements

    NASA Astrophysics Data System (ADS)

    Tarabini, Marco; Saggin, Bortolino; Scaccabarozzi, Diego; Moschioni, Giovanni

    2012-01-01

    This paper evaluates the advantages and the drawbacks deriving from the use of MEMS (micro-electro-mechanical systems) accelerometers for hand-arm and whole-body vibration measurements. Metrological performances of different transducers were assessed through the identification of their frequency response function, linearity, floor noise and sensitivity to thermal and electromagnetic disturbances. Experimental results highlighted a standard instrumental uncertainty (including the nonlinearity) lower than 5% with the single frequency calibration procedure, such a value was reduced to 2%. The temperature effect was negligible and the electromagnetic disturbances sensitivity was comparable to that of the piezoelectric accelerometers. The compatibility of measurements obtained with MEMS accelerometers with those of piezoelectric-based measurement chains was verified for two specific applications. An example of direct transducer fixation on the skin for vibration transmissibility measurements is also presented. Thanks to the MEMS peculiarities - mainly small sizes and low cost - since novel approaches in the vibration monitoring could be pursued. For instance, it is possible to include by design MEMS accelerometers in any hand-held tool at the operator interface, or inside the seats structures of cars, tractors and trucks. This could be a viable solution to easily obtain repeatable exposure measurements and could also provide diagnostic signals for the tools or seats of functional monitoring.

  19. Hard quasiamorphous carbon -- A prospective construction material for micro-electro-mechanical systems

    SciTech Connect

    Dorfman, B.F. |; Asoka-Kumar, P.; Zhu, Q.; Pollak, F.H.; Wan, J.Z.

    1996-01-01

    A new form of sp{sup 3}/sp{sup 2} carbon has been fabricated which exhibits a large number of valuable properties. This material combines low density ({le} 1.65 g/cm{sup 3}), low stress ({le} 0.05 GPa), low thermal expansion(1.6 x 10{sup {minus}6} K{sup {minus}1}) with high hardness ({approximately} 30 GPa), modulus ({approximately} 200 GPa), cracking threshold ({ge} 3 N), fracture toughness ({ge} 10 MPa-m{sup 1/2}), long-term thermal stability ({ge} 450 C in air and {ge} 600 C without oxygen), extremely high thermal shock resistance, excellent interface and adhesion to silicon, metals, and ceramics and an absolute resistance to the silicon etching acids. Mot of its properties are actually constant up to 700 K. The material combines a basically amorphous structure with one-axis anisotropy and a graphite-like layered arrangement with a length scale of the modulation about 14 {angstrom}. The authors refer to this quasi-amorphous material as QUASAM. This paper describes QUASAM synthesis conditions, growth front planarity and material characterization with high-resolution x-ray diffraction, positron annihilation spectroscopy, atomic force microscopy and micro-Raman spectroscopy. In addition the mechanical and thermal examination of QUASAM and QUASAM/Si will be presented in terms of micro-electro-mechanical systems (MEMS) and the technology prospective requirements of MEMS.

  20. Comb-drive micro-electro-mechanical systems oscillators for low temperature experiments.

    PubMed

    González, M; Zheng, P; Garcell, E; Lee, Y; Chan, H B

    2013-02-01

    We have designed and characterized micro-electro-mechanical systems (MEMS) for applications at low temperatures. The mechanical resonators were fabricated using a surface micromachining process. The devices consist of a pair of parallel plates with a well defined gap. The top plate can be actuated for shear motion relative to the bottom fixed plate through a set of comb-drive electrodes. Details on the operation and fabrication of the devices are discussed. The geometry was chosen to study the transport properties of the fluid entrained in the gap. An atomic force microscopy study was performed in order to characterize the surface. A full characterization of their resonance properties in air and at room temperature was conducted as a function of pressure, from 10 mTorr to 760 Torr, ranging from a highly rarefied gas to a hydrodynamic regime. We demonstrate the operation of our resonator at low temperatures immersed in superfluid (4)He and in the normal and superfluid states of (3)He down to 0.3 mK. These MEMS oscillators show potential for use in a wide range of low temperature experiments, in particular, to probe novel phenomena in quantum fluids. PMID:23464242

  1. RF Micro-Electro-Mechanical Systems Capacitive Switches Using Ultra Thin Hafnium Oxide Dielectric

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Onodera, Kazumasa; Maeda, Ryutaro

    2006-01-01

    A π-type RF capacitive switch using about 45-nm-thick HfO2 dielectric layer was fabricated. High isolation performance was obtained in wide-band range when the switch was down-state. The isolation was better than -40 dB at the frequency range of 4-35 GHz. Particularly, the isolation was better than -50 dB in the frequency range of 8-12 GHz, i.e., X band. HfO2 showed excellent process compatibility with conventional microfabrication procedure. The 45-nm-thick HfO2 film was prepared using sputtering at room temperature so that it was feasible to be integrated into RF switch and other microwave circuits. The results of constant bias stressing showed that the ultra thin HfO2 had excellent reliability. The electric breakdown of HfO2 was observed, which had no apparent negative effects on the reliability of the dielectric. HfO2 dielectrics were attractive in the application of RF micro-electro-mechanical systems (MEMS) switch for new generation of low-loss high-linearity microwave circuits.

  2. Experimental Identification of Smartphones Using Fingerprints of Built-In Micro-Electro Mechanical Systems (MEMS).

    PubMed

    Baldini, Gianmarco; Steri, Gary; Dimc, Franc; Giuliani, Raimondo; Kamnik, Roman

    2016-01-01

    The correct identification of smartphones has various applications in the field of security or the fight against counterfeiting. As the level of sophistication in counterfeit electronics increases, detection procedures must become more accurate but also not destructive for the smartphone under testing. Some components of the smartphone are more likely to reveal their authenticity even without a physical inspection, since they are characterized by hardware fingerprints detectable by simply examining the data they provide. This is the case of MEMS (Micro Electro-Mechanical Systems) components like accelerometers and gyroscopes, where tiny differences and imprecisions in the manufacturing process determine unique patterns in the data output. In this paper, we present the experimental evaluation of the identification of smartphones through their built-in MEMS components. In our study, three different phones of the same model are subject to repeatable movements (composing a repeatable scenario) using an high precision robotic arm. The measurements from MEMS for each repeatable scenario are collected and analyzed. The identification algorithm is based on the extraction of the statistical features of the collected data for each scenario. The features are used in a support vector machine (SVM) classifier to identify the smartphone. The results of the evaluation are presented for different combinations of features and Inertial Measurement Unit (IMU) outputs, which show that detection accuracy of higher than 90% is achievable. PMID:27271630

  3. Mechatronic Scanning System with Integrated Micro Electro Mechanical System Position Sensors

    NASA Astrophysics Data System (ADS)

    Stavrov, Vladimir; Chakarov, Dimitar; Shulev, Assen; Tsveov, Mihail

    2016-06-01

    In this paper, a study of a mechatronic scanning system for application in the microbiology, microelectronics research, chemistry, etc. is presented. Integrated silicon micro electro mechanical system (MEMS) position sensor is used for monitoring the displacement of the scanning system. The utilized silicon MEMS sensors with sidewall embedded piezoresistors possess a number of key advantages such as high sensitivity, low noise and extremely low temperature dependence. Design of 2D scanning system with a travel range of 22 × 22 μm2 has been presented in present work. This system includes a Compliant Transmission Mechanism, (CTM) designed as a complex elastic mechanism, comprising four parallelograms. Computer aided desigh (CAD) model and finite element analysis (FEA) of the Compliant Transmission Mechanism mechanisms have been carried out. A prototype of the scanning system is fabricated, based on CAD model. An experimental set-up of an optical system and a correlation technique for digital image processing have been used for testing the scanning system prototype. Results of the experimental investigations of the prototyped scanning system are also presented.

  4. Micromachining of an SU-8 flapping-wing flying micro-electro-mechanical system

    NASA Astrophysics Data System (ADS)

    Dargent, T.; Bao, X. Q.; Grondel, S.; Brun, G. Le; Paquet, J. B.; Soyer, C.; Cattan, E.

    2009-08-01

    This paper presents a feasibility step in the development of an ultra-small biomimetic flying machine. Advanced engineering technologies available for applications such as the micro-electro-mechanical system (MEMS) technologies are used. To achieve this goal, a flapping-wing flying MEMS concept and design inspired from insects is first described. Actuators and an actuation way for the control over the wing kinematics are proposed. The initial concepts are subsequently analyzed and presented using multi-body and finite element models. An overview of SU-8 photoresist structures and their functions in the future micro-robot insect is then presented. Consequently, micromachining enables the implementation of a flying MEMS. It is also demonstrated that the structure can be made at insect sizes and actuated at low power inputs. Moreover, the flapping frequency obtained is within the flapping frequency range of wings of many common insects of millimetric dimensions. Such prototypes are of interest as tools to artificially recreate and study insect flight with characteristics, similar to those of insects, that are able to produce lift and hover. Finally, if a micro-battery, wireless receivers, microcontrollers, sensors and actuators can all be fitted onto chips only a few millimeters square, with a mass in the order of milligrams, then we believe that an insect-size flying MEMS can be realized. All these requirements can now be achieved due to advanced engineering methods.

  5. Fabrication processes for MEMS deformable mirrors in the next generation telescope instruments

    NASA Astrophysics Data System (ADS)

    Diouf, Alioune

    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 2.5microm 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

  6. Analysis of the "Push-pull" Capacitance Bridge Circuit for Comb-Drive Micro-electro-mechanical Oscillators

    NASA Astrophysics Data System (ADS)

    Zheng, P.; Jiang, W. G.; Barquist, C. S.; Lee, Y.; Chan, H. B.

    2016-05-01

    We have developed an improved actuation/detection scheme for a comb-drive micro-electro-mechanical oscillator as a probe to study quantum fluids. This symmetric scheme has many advantages over the asymmetric scheme used previously. In this report, we provide a full description and analysis of the method so that researchers interested can readily implement the method in their experiments involving similar devices.

  7. MEMS (Micro-Electro-Mechanical Systems) for Automotive and Consumer Electronics

    NASA Astrophysics Data System (ADS)

    Marek, Jiri; Gómez, Udo-Martin

    MEMS sensors gained over the last two decades an impressive width of applications: (a) ESP: A car is skidding and stabilizes itself without driver intervention (b) Free-fall detection: A laptop falls to the floor and protects the hard drive by parking the read/write drive head automatically before impact. (c) Airbag: An airbag fires before the driver/occupant involved in an impending automotive crash impacts the steering wheel, thereby significantly reducing physical injury risk. MEMS sensors are sensing the environmental conditions and are giving input to electronic control systems. These crucial MEMS sensors are making system reactions to human needs more intelligent, precise, and at much faster reaction rates than humanly possible. Important prerequisites for the success of sensors are their size, functionality, power consumption, and costs. This technical progress in sensor development is realized by micro-machining. The development of these processes was the breakthrough to industrial mass-production for micro-electro-mechanical systems (MEMS). Besides leading-edge micromechanical processes, innovative and robust ASIC designs, thorough simulations of the electrical and mechanical behaviour, a deep understanding of the interactions (mainly over temperature and lifetime) of the package and the mechanical structures are needed. This was achieved over the last 20 years by intense and successful development activities combined with the experience of volume production of billions of sensors. This chapter gives an overview of current MEMS technology, its applications and the market share. The MEMS processes are described, and the challenges of MEMS, compared to standard IC fabrication, are discussed. The evolution of MEMS requirements is presented, and a short survey of MEMS applications is shown. Concepts of newest inertial sensors for ESP-systems are given with an emphasis on the design concepts of the sensing element and the evaluation circuit for achieving

  8. Open-loop control of SCExAO's MEMS deformable mirror using the Fast Iterative Algorithm: speckle control performances

    NASA Astrophysics Data System (ADS)

    Blain, Célia; Guyon, Olivier; Martinache, Frantz; Bradley, Colin; Clergeon, Christophe

    2012-07-01

    Micro-Electro-Mechanical Systems (MEMS) deformable mirrors (DMs) are widely utilized in astronomical Adaptive Optics (AO) instrumentation. High precision open-loop control of MEMS DMs has been achieved by developing a high accuracy DM model, the Fast Iterative Algorithm (FIA), a physics-based model allowing precise control of the DM shape. Accurate open-loop control is particularly critical for the wavefront control of High- Contrast Imaging (HCI) instruments to create a dark hole area free of most slow and quasi-static speckles which remain the limiting factor for direct detection and imaging of exoplanets. The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system is one of these high contrast imaging instruments and uses a 1024-actuator MEMS deformable mirror (DM) both in closed-loop and open-loop. The DM is used to modulate speckles in order to distinguish (i) speckles due to static and slow-varying residual aberrations from (ii) speckles due to genuine structures, such as exoplanets. The FIA has been fully integrated into the SCExAO wavefront control software and we report the FIA’s performance for the control of speckles in the focal plane.

  9. Shape memory composite deformable mirrors

    NASA Astrophysics Data System (ADS)

    Riva, M.; Bettini, P.; Di Landro, L.; Sala, G.

    2009-03-01

    This paper deals with some of the critical aspects regarding Shape Memory Composite (SMC) design: firstly some technological aspects concerning embedding technique and their efficiency secondarily the lack of useful numerical tools for this peculiar design. It has been taken into account as a possible application a deformable panel which is devoted to act as a substrate for a deformable mirror. The activity has been mainly focused to the study of embedding technologies, activation and authority. In detail it will be presented the "how to" manufacturing of some smart panels with embedded NiTiNol wires in order to show the technology developed for SMC structures. The first part of the work compares non conventional pull-out tests on wires embedded in composites laminates (real condition of application), with standard pull-out in pure epoxy resin blocks. Considering the numerical approach some different modeling techniques to be implemented in commercial codes (ABAQUS) have been investigated. The Turner's thermo-mechanical model has been adopted for the modeling of the benchmark: A spherical panel devoted to work as an active substrate for a Carbon Fiber Reinforced Plastic (CFRP) deformable mirror has been considered as a significant technological demonstrator and possible future application (f=240mm, r.o.c.=1996mm).

  10. Parametric resonance voltage response of electrostatically actuated Micro-Electro-Mechanical Systems cantilever resonators

    NASA Astrophysics Data System (ADS)

    Caruntu, Dumitru I.; Martinez, Israel; W. Knecht, Martin

    2016-02-01

    This paper investigates the parametric resonance voltage response of nonlinear parametrically actuated Micro-Electro-Mechanical Systems (MEMS) cantilever resonators. A soft AC voltage of frequency near natural frequency is applied between the resonator and a parallel ground plate. This produces an electrostatic force that leads the structure into parametric resonance. The model consists of an Euler-Bernoulli thin cantilever under the actuation of electrostatic force to include fringe effect, and damping force. Two methods of investigation are used, namely the Method of Multiple Scales (MMS) and Reduced Order Model (ROM) method. ROM convergence of the voltage response and the limitation of MMS to small to moderate amplitudes with respect to the gap (gap-amplitudes) are reported. MMS predicts accurately both Hopf supercritical and supercritical bifurcation voltages. However, MMS overestimates the large gap-amplitudes of the resonator, and. misses completely or overestimates the saddle-node bifurcation occurring at large gap-amplitudes. ROM produces valid results for small and/or large gap-amplitudes for a sufficient number of terms (vibration modes). As the voltage is swept up at constant frequency, the resonator maintains zero amplitude until reaches the subcritical Hopf bifurcation voltage where it loses stability and jumps up to large gap-amplitudes, next the gap-amplitude decreases until it reaches the supercritical Hopf bifurcation point, and after that the gap-amplitude remains zero, for the voltage range considered in this work. As the voltage is swept down at constant frequency, the zero gap-amplitude of the resonator starts increasing continuously after reaching the supercritical Hopf bifurcation voltage until it reaches the saddle-node bifurcation voltage when a sudden jump to zero gap-amplitude occurs. Effects of frequency, damping and fringe parameters on the voltage response show that (1) the supercritical Hopf bifurcation is shifted to lower voltage

  11. Optical Spatial Heterodyned Interferometry for Inspection of Micro-Electro-Mechanical Systems

    SciTech Connect

    Tobin Jr, Kenneth William; Bingham, Philip R; Price, Jeffery R

    2005-01-01

    Interferometric imaging has the potential to extend the usefulness of optical microscopes by encoding small phase shifts that reveal information about topology and materials. At the Oak Ridge National Laboratory (ORNL), we have developed an optical Spatial Heterodyne Interferometry (SHI) method that captures reflection images containing both phase and amplitude information at a high rate of speed. By measuring the phase of a wavefront reflected off or transmitted through a surface, the relative surface heights and some materials properties can be measured. In this paper we briefly review our historical application of SHI in the semiconductor industry, but the focus is on new research to adapt this technology to the inspection of MEMS devices, in particular to the characterization of motion elements such as microcantilevers and deformable mirror arrays.

  12. Deformable Mirrors Correct Optical Distortions

    NASA Technical Reports Server (NTRS)

    2010-01-01

    By combining the high sensitivity of space telescopes with revolutionary imaging technologies consisting primarily of adaptive optics, the Terrestrial Planet Finder is slated to have imaging power 100 times greater than the Hubble Space Telescope. To this end, Boston Micromachines Corporation, of Cambridge, Massachusetts, received Small Business Innovation Research (SBIR) contracts from the Jet Propulsion Laboratory for space-based adaptive optical technology. The work resulted in a microelectromechanical systems (MEMS) deformable mirror (DM) called the Kilo-DM. The company now offers a full line of MEMS DMs, which are being used in observatories across the world, in laser communication, and microscopy.

  13. Control model for a continuous face sheet, MEMS based deformable membrane mirror

    NASA Astrophysics Data System (ADS)

    Carreras, R. A.; Marker, D. K.; Wilkes, J. M.

    2005-08-01

    Small Micro-Electro-Mechanical Systems (MEMS) deformable mirror (DM) technology is of great interest to the adaptive optics (AO) community. These MEMS-DM's are being considered for many conventional AO applications since they posses some advantages over conventional DM's. The MEMS-DM technology is driven by the expectation of achieving improved performance with lower costs, low electrical power, high number of actuators, high production rates, and large reductions in structural mass and volume. In addition to the imaging community, the directed energy community is also interested in taking advantage of the characteristics which MEMS-DM's offer. Unlike imaging, the optical fill-factor of a high-energy laser DM, has to be essentially 100 percent! Many modern MEMS-DM designs consist of small, lightweight, segmented mirrors that can be precisely controlled. For high-energy laser applications, the MEMS DM's should have a continuous reflective face-sheet with no gaps. This continuous reflective face-sheet must include high-energy laser coatings, which render the face sheet very stiff. This is a new challenge for MEMS-DM's, which has not previously been addressed. The Air Force Research Laboratory has proposed to meet this challenge with several continuous face-sheet high-energy laser MEMS-DM's designs. This paper will give a generic description of a MEMS-DM computer model. The research goal is to develop a MEMS-DM model for closed loop control of a high-energy laser, MEMS-DM adaptive optics application.

  14. Stressed mirror polishing: finite element simulation of mirror blank deformation

    NASA Astrophysics Data System (ADS)

    Han, Yu; Lu, Lihong

    2014-08-01

    The theoretical principle of Stressed Mirror Polishing (SMP) is introduced, including the representation method of elastic deformation, the formulations of discrete bending moment and shearing force. A Finite Element Analysis (FEA) simulation model of has been set up by ANSYS software. The warping facility in this model is consisted of 36 aluminum alloy arms equally distribute on the ambit of mirror blank. Two forces are applied on each arm to provide bending moment and shearing force. Taking type 82 segment of Thirty Meters Telescope (TMT) primary mirror for example, a FEA simulation of mirror blank deformation has been performed. Simulation result shows that, the deformation error is 33μm PV. The theoretical deformation PV value is 205μm and the simulation deformation PV value is 172μm, converging rate reaches to 0.84 in a single warping cycle. After three or four warping cycles, the residue error may converge into 1μm.

  15. Chaos control of the micro-electro-mechanical resonator by using adaptive dynamic surface technology with extended state observer

    NASA Astrophysics Data System (ADS)

    Luo, Shaohua; Sun, Quanping; Cheng, Wei

    2016-04-01

    This paper addresses chaos control of the micro-electro- mechanical resonator by using adaptive dynamic surface technology with extended state observer. To reveal the mechanism of the micro- electro-mechanical resonator, the phase diagrams and corresponding time histories are given to research the nonlinear dynamics and chaotic behavior, and Homoclinic and heteroclinic chaos which relate closely with the appearance of chaos are presented based on the potential function. To eliminate the effect of chaos, an adaptive dynamic surface control scheme with extended state observer is designed to convert random motion into regular motion without precise system model parameters and measured variables. Putting tracking differentiator into chaos controller solves the `explosion of complexity' of backstepping and poor precision of the first-order filters. Meanwhile, to obtain high performance, a neural network with adaptive law is employed to approximate unknown nonlinear function in the process of controller design. The boundedness of all the signals of the closed-loop system is proved in theoretical analysis. Finally, numerical simulations are executed and extensive results illustrate effectiveness and robustness of the proposed scheme.

  16. High stroke pixel for a deformable mirror

    DOEpatents

    Miles, Robin R.; Papavasiliou, Alexandros P.

    2005-09-20

    A mirror pixel that can be fabricated using standard MEMS methods for a deformable mirror. The pixel is electrostatically actuated and is capable of the high deflections needed for spaced-based mirror applications. In one embodiment, the mirror comprises three layers, a top or mirror layer, a middle layer which consists of flexures, and a comb drive layer, with the flexures of the middle layer attached to the mirror layer and to the comb drive layer. The comb drives are attached to a frame via spring flexures. A number of these mirror pixels can be used to construct a large mirror assembly. The actuator for the mirror pixel may be configured as a crenellated beam with one end fixedly secured, or configured as a scissor jack. The mirror pixels may be used in various applications requiring high stroke adaptive optics.

  17. Integrated dual-stage deformable mirrors

    NASA Astrophysics Data System (ADS)

    Griffith, Mike; Laycock, Leslie; Archer, Nick; Myers, Richard; Kirby, Andrew; Doel, Peter; Brooks, David

    2010-07-01

    We present the results of a study on Dual-Stage Deformable Mirrors using Zonal Bimorph Deformable Mirror (ZBDM) technology. A high density 'tweeter' DM has been assembled onto a lower density, high dynamic range 'woofer' DM to generate an integrated mirror which offers both high resolution and dynamic range simultaneously. Such a device has the potential to significantly simplify the design of astronomical Adaptive Optics (AO) systems. The latest developments are presented, including the fabrication of a small scale demonstrator.

  18. Deformable mirror for short wavelength applications

    DOEpatents

    Chapman, Henry N.; Sweeney, Donald W.

    1999-01-01

    A deformable mirror compatible with short wavelength (extreme ultraviolet) radiation that can be precisely controlled to nanometer and subnanometer accuracy is described. Actuators are coupled between a reaction plate and a face plate which has a reflective coating. A control system adjusts the voltage supplied to the actuators; by coordinating the voltages supplied to the actuators, the reflective surface of the mirror can be deformed to correct for dimensional errors in the mirror or to produce a desired contour.

  19. CubeSat deformable mirror demonstration

    NASA Astrophysics Data System (ADS)

    Cahoy, Kerri; Marinan, Anne; Kerr, Caitlin; Cheng, Kezi; Jamil, Sara

    2012-09-01

    The goal of the CubeSat Deformable Mirror Demonstration (DeMi) is to characterize the performance of a small deformable mirror over a year in low-Earth orbit. Small form factor deformable mirrors are a key technology needed to correct optical system aberrations in high contrast, high dynamic range space telescope applications such as space-based coronagraphic direct imaging of exoplanets. They can also improve distortions and reduce bit error rates for space-based laser communication systems. While follow-on missions can take advantage of this general 3U CubeSat platform to test the on-orbit performance of several different types of deformable mirrors, this first design accommodates a 32-actuator Boston Micromachines MEMS deformable mirror.

  20. Deformable Mirror Materials Issue Assessment

    SciTech Connect

    Rudd, R E

    2008-05-27

    It was a pleasure to speak with you and Dr. Olivier Guyon about your project to develop a coronagraph and in particular about materials science considerations in the development of the deformable mirror (DM) for the coronagraph. The coronagraph application will demand more of a DM than previous applications with regard to precision, and since the characterization and modeling tools are currently under development, you asked me to comment on materials issues that might impact the DM design and testing. I have not conducted research on this question, and my own research on modeling MEMS has not included DM systems. I am only in a position to discuss some general considerations that may help in developing a research plan for the DM system. As I understand it, the relevant points about the DM system are as follows. The DM surface needs to be positioned to less than 1 {angstrom} RMS of the desired shape, and be stable to 0.3 {angstrom} RMS for an hour. In the ultimate application in space the stability requirements may be greater. For example, the DM shape can be set using a bright star and then allow the coronagraph to be turned to a dim star to collect data for several hours, counting on the mirror shape to be stable. The DM is made of a polysilicon membrane coated with one or more metal layers for the reflective surface and actuated by 32x32 or 64x64 electrostatic actuators on the back side. The uncertainty in the position of any one actuator should be at the few-picometer level or less averaged over the 300-{micro}m region of the actuator. Currently, experiments are conducted that can characterize the surface shape to the 1 nm level, and it is anticipated that the experiments will be able to characterize the shape at the sub-Angstrom level but not in the immediate future. Regarding stability, under relatively large deformations (10's of nm), the DM mirror surface shows no hysteresis at the measurable nm level. Let me begin by saying that I am not aware of any

  1. A ferrofluidic deformable mirror for ophthalmology

    NASA Astrophysics Data System (ADS)

    Macpherson, J. B.; Thibault, S.; Borra, E. F.; Ritcey, A. M.; Carufel, N.; Asselin, D.; Jerominek, H.; Campbell, M. C. W.

    2005-09-01

    Optical aberrations reduce the imaging quality of the human eye. In addition to degrading vision, this limits our ability to illuminate small points of the retina for therapeutic, surgical or diagnostic purposes. When viewing the rear of the eye, aberrations cause structures in the fundus to appear blurred, limiting the resolution of ophthalmoscopes (diagnostic instruments used to image the eye). Adaptive optics, such as deformable mirrors may be used to compensate for aberrations, allowing the eye to work as a diffraction-limited optical element. Unfortunately, this type of correction has not been widely available for ophthalmic applications because of the expense and technical limitations of current deformable mirrors. We present preliminary design and characterisation of a deformable mirror suitable for ophthalmology. In this ferrofluidic mirror, wavefronts are reflected from a fluid whose surface shape is controlled by a magnetic field. Challenges in design are outlined, as are advantages over traditional deformable mirrors.

  2. Modelling MEMS deformable mirrors for astronomical adaptive optics

    NASA Astrophysics Data System (ADS)

    Blain, Celia

    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 onaxis 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

  3. Bias Dependence of Gallium Nitride Micro-Electro-Mechanical Systems Actuation Using a Two-Dimensional Electron Gas

    NASA Astrophysics Data System (ADS)

    Amar, Achraf Ben; Faucher, Marc; Grimbert, Bertrand; Cordier, Yvon; Fran\\{c}ois, Marc; Tilmant, Pascal; Werquin, Matthieu; Zhang, Victor; Ducatteau, Damien; Gaquière, Christophe; Buchaillot, Lionel; Théron, Didier

    2012-06-01

    The piezoelectric actuation of a micro-electro-mechanical system (MEMS) resonator based on an AlGaN/GaN heterostructure is studied under various bias conditions. Using an actuator electrode that is also a transistor gate, we correlate the mechanical behaviour to the two-dimensional electron gas (2DEG) presence. The measured amplitude of the actuated resonator is maximum at moderate negative biases and drops near the pinch-off voltage in concordance with the 2DEG becoming depleted. Below the pinch-off voltage, residual actuation is still present, which is attributed to a more complex electric field pattern supported by quantitative modelling. The results confirm that epitaxial AlGaN barriers are fully adapted to the piezoelectric actuation of MEMS.

  4. Compliant deformable mirror approach for wavefront improvement

    NASA Astrophysics Data System (ADS)

    Clark, James H.; Penado, F. Ernesto

    2016-04-01

    We describe a compliant static deformable mirror approach to reduce the wavefront concavity at the Navy Precision Optical Interferometer (NPOI). A single actuator pressing on the back surface of just one of the relay mirrors deforms the front surface in a correcting convex shape. Our design uses the mechanical advantage gained from a force actuator sandwiched between a rear flexure plate and the back surface of the mirror. We superimpose wavefront contour measurements with our finite element deformed mirror model. An example analysis showed improvement from 210-nm concave-concave wavefront to 51-nm concave-concave wavefront. With our present model, a 100-nm actuator increment displaces the mirror surface by 1.1 nm. We describe the need for wavefront improvement that arises from the NPOI reconfigurable array, offer a practical design approach, and analyze the support structure and compliant deformable mirror using the finite element method. We conclude that a 20.3-cm-diameter, 1.9-cm-thick Zerodur® mirror shows that it is possible to deform the reflective surface and cancel out three-fourths of the wavefront deformation without overstressing the material.

  5. Micro-electro-mechanical systems/near-infrared validation of different sampling modes and sample sets coupled with multiple models.

    PubMed

    Wu, Zhisheng; Shi, Xinyuan; Wan, Guang; Xu, Manfei; Zhan, Xueyan; Qiao, Yanjiang

    2015-01-01

    The aim of the present study was to demonstrate the reliability of micro-electro-mechanical systems/near-infrared technology by investigating analytical models of two modes of sampling (integrating sphere and fiber optic probe modes) and different sample sets. Baicalin in Yinhuang tablets was used as an example, and the experimental procedure included the optimization of spectral pretreatments, selection of wavelength regions using interval partial least squares, moving window partial least squares, and validation of the method using an accuracy profile. The results demonstrated that models that use the integrating sphere mode are better than those that use fiber optic probe modes. Spectra that use fiber optic probe modes tend to be more susceptible to interference information because the intensity of the incident light on a fiber optic probe mode is significantly weaker than that on an integrating sphere mode. According to the test set validation result of the method parameters, such as accuracy, precision, risk, and linearity, the selection of variables was found to make no significant difference to the performance of the full spectral model. The performance of the models whose sample sets ranged widely in concentration (i.e., 1-4 %) was found to be better than that of models whose samples had relatively narrow ranges (i.e., 1-2 %). The establishment and validation of this method can be used to clarify the analytical guideline in Chinese herbal medicine about two sampling modes and different sample sets in the micro-electro-mechanical systems/near-infrared technique. PMID:25626144

  6. Novel technologies for small deformable mirrors

    NASA Astrophysics Data System (ADS)

    Strachan, Mel; Myers, Richard; Cooke, Kevin; Hampshire, Joanne; Hough, Jim; Rowan, Sheila; van Veggel, Marielle; Kirk, Katherine; Hutson, David; Uzgur, Erman; Kim, Shin-Sung

    2010-07-01

    Adaptive optic requirements for instrumentation such as EAGLE for the European extremely large telescope present an enormous challenge to deformable mirror technology. We have developed a unique approach using fabricated arrays of multilayer actuator technology to address the requirements of actuator density and deflection. Our programme of work has uncovered a novel approach which has led to a built in test capability. We will present the outcomes of our work which we believe will lead to a compact deformable mirror.

  7. Smart materials fabrication and materials for micro-electro-mechanical systems; Symposium Proceedings, San Francisco, CA, Apr. 28-30, 1992

    NASA Technical Reports Server (NTRS)

    Jardine, A. Peter (Editor); Johnson, George C. (Editor); Crowson, Andrew (Editor); Allen, Mark (Editor)

    1992-01-01

    A conference on the rapidly developing fields of `smart materials' and micro-electro-mechanical systems produced papers in the areas of fabrication and characterization of ferroelectric thin films; polycrystalline silicon; optical, chemical, and biological sensors; thin film shape memory alloys; materials characterization; and alternative materials and applications.

  8. Infrastructure, Technology and Applications of Micro-Electro-Mechanical Systems (MEMS)

    SciTech Connect

    Allen, J.J.; Jakubczak, J.F.; Krygowski, T.W.; Miller, S.L.; Montague, S.; Rodgers, M.S.; Sniegowski, J.J.

    1999-07-09

    A review is made of the infrastructure, technology and capabilities of Sandia National Laboratories for the development of micromechanical systems. By incorporating advanced fabrication processes, such as chemical mechanical polishing, and several mechanical polysilicon levels, the range of micromechanical systems that can be fabricated in these technologies is virtually limitless. Representative applications include a micro-engine driven mirror, and a micromachined lock. Using a novel integrated MEMS/CMOS technology, a six degree-of-freedom accelerometer/gyroscope system has been designed by researchers at U.C. Berkeley and fabricated on the same silicon chip as the CMOS control circuits to produce an integrated micro-navigational unit.

  9. Evaluation of performance of portable respiratory monitoring system based on micro-electro-mechanical-system for respiratory gated radiotherapy

    NASA Astrophysics Data System (ADS)

    Moon, Sun Young; Sung, Jiwon; Yoon, Myonggeun; Chung, Mijoo; Chung, Weon Kuu; Kim, Dong Wook

    2015-08-01

    In respiratory-gated radiotherapy of patients with lung or liver cancer, the patient's respiratory pattern and repeatability are important factors affecting therapy accuracy; it has been reported that these factors can be controlled if patients undergo respiration training. As such, this study evaluates the feasibility of micro-electro-mechanical-system (MEMS) in radiotherapy by investigating the effect of radiation on a miniature portable respiratory monitoring system based on the MEMS system, which is currently under development. Using a patient respiration simulation phantom, the time-acceleration graph measured by a normal sensor according to the phantom's respiratory movement before irradiation and the change in this graph with accumulated dose were compared using the baseline slope and the change in amplitude and period of the sine wave. The results showed that with a 400Gy accumulated dose in the sensor, a baseline shift occurred and both the amplitude and period changed. As a result, if the MEMS is applied in respiratory-gated radiotherapy, the sensor should be replaced after use with roughly 6-10 patients so as to ensure continued therapy accuracy, based on the characteristics of the sensor itself. In the future, a more diverse range of sensors should be similarly evaluated.

  10. Utilizing micro-electro-mechanical systems (MEMS) micro-shutter designs for adaptive coded aperture imaging (ACAI) technologies

    NASA Astrophysics Data System (ADS)

    Ledet, Mary M.; Starman, LaVern A.; Coutu, Ronald A., Jr.; Rogers, Stanley

    2009-08-01

    Coded aperture imaging (CAI) has been used in both the astronomical and medical communities for years due to its ability to image light at short wavelengths and thus replacing conventional lenses. Where CAI is limited, adaptive coded aperture imaging (ACAI) can recover what is lost. The use of photonic micro-electro-mechanical-systems (MEMS) for creating adaptive coded apertures has been gaining momentum since 2007. Successful implementation of micro-shutter technologies would potentially enable the use of adaptive coded aperture imaging and non-imaging systems in current and future military surveillance and intelligence programs. In this effort, a prototype of MEMS microshutters has been designed and fabricated onto a 3 mm x 3 mm square of silicon substrate using the PolyMUMPSTM process. This prototype is a line-drivable array using thin flaps of polysilicon to cover and uncover an 8 x 8 array of 20 μm apertures. A characterization of the micro-shutters to include mechanical, electrical and optical properties is provided. This prototype, its actuation scheme, and other designs for individual microshutters have been modeled and studied for feasibility purposes. In addition, microshutters fabricated from an Al-Au alloy on a quartz wafer were optically tested and characterized with a 632 nm HeNe laser.

  11. Development of High Precision Metal Micro-Electro-Mechanical-Systems Column for Portable Surface Acoustic Wave Gas Chromatograph

    NASA Astrophysics Data System (ADS)

    Iwaya, Takamitsu; Akao, Shingo; Sakamoto, Toshihiro; Tsuji, Toshihiro; Nakaso, Noritaka; Yamanaka, Kazushi

    2012-07-01

    In the field of environmental measurement and security, a portable gas chromatograph (GC) is required for the on-site analysis of multiple hazardous gases. Although the gas separation column has been downsized using micro-electro-mechanical-systems (MEMS) technology, an MEMS column made of silicon and glass still does not have sufficient robustness and a sufficiently low fabrication cost for a portable GC. In this study, we fabricated a robust and inexpensive high-precision metal MEMS column by combining diffusion-bonded etched stainless-steel plates with alignment evaluation using acoustic microscopy. The separation performance was evaluated using a desktop GC with a flame ionization detector and we achieved the high separation performance comparable to the best silicon MEMS column fabricated using a dynamic coating method. As an application, we fabricated a palm-size surface acoustic wave (SAW) GC combining this column with a ball SAW sensor and succeeded in separating and detecting a mixture of volatile organic compounds.

  12. An adaptive compensation algorithm for temperature drift of micro-electro-mechanical systems gyroscopes using a strong tracking Kalman filter.

    PubMed

    Feng, Yibo; Li, Xisheng; Zhang, Xiaojuan

    2015-01-01

    We present an adaptive algorithm for a system integrated with micro-electro-mechanical systems (MEMS) gyroscopes and a compass to eliminate the influence from the environment, compensate the temperature drift precisely, and improve the accuracy of the MEMS gyroscope. We use a simplified drift model and changing but appropriate model parameters to implement this algorithm. The model of MEMS gyroscope temperature drift is constructed mostly on the basis of the temperature sensitivity of the gyroscope. As the state variables of a strong tracking Kalman filter (STKF), the parameters of the temperature drift model can be calculated to adapt to the environment under the support of the compass. These parameters change intelligently with the environment to maintain the precision of the MEMS gyroscope in the changing temperature. The heading error is less than 0.6° in the static temperature experiment, and also is kept in the range from 5° to -2° in the dynamic outdoor experiment. This demonstrates that the proposed algorithm exhibits strong adaptability to a changing temperature, and performs significantly better than KF and MLR to compensate the temperature drift of a gyroscope and eliminate the influence of temperature variation. PMID:25985165

  13. An Adaptive Compensation Algorithm for Temperature Drift of Micro-Electro-Mechanical Systems Gyroscopes Using a Strong Tracking Kalman Filter

    PubMed Central

    Feng, Yibo; Li, Xisheng; Zhang, Xiaojuan

    2015-01-01

    We present an adaptive algorithm for a system integrated with micro-electro-mechanical systems (MEMS) gyroscopes and a compass to eliminate the influence from the environment, compensate the temperature drift precisely, and improve the accuracy of the MEMS gyroscope. We use a simplified drift model and changing but appropriate model parameters to implement this algorithm. The model of MEMS gyroscope temperature drift is constructed mostly on the basis of the temperature sensitivity of the gyroscope. As the state variables of a strong tracking Kalman filter (STKF), the parameters of the temperature drift model can be calculated to adapt to the environment under the support of the compass. These parameters change intelligently with the environment to maintain the precision of the MEMS gyroscope in the changing temperature. The heading error is less than 0.6° in the static temperature experiment, and also is kept in the range from 5° to −2° in the dynamic outdoor experiment. This demonstrates that the proposed algorithm exhibits strong adaptability to a changing temperature, and performs significantly better than KF and MLR to compensate the temperature drift of a gyroscope and eliminate the influence of temperature variation. PMID:25985165

  14. MEMS deformable mirrors for astronomical adaptive optics

    NASA Astrophysics Data System (ADS)

    Cornelissen, S. A.; Hartzell, A. L.; Stewart, J. B.; Bifano, T. G.; Bierden, P. A.

    2010-07-01

    We report on the development of high actuator count, micro-electromechanical (MEMS) deformable mirrors designed for high order wavefront correction in ground and space-based astronomical adaptive optics instruments. The design of these polysilicon, surface-micromachined MEMS deformable mirrors builds on technology that has been used extensively to correct for ocular aberrations in retinal imaging systems and for compensation of atmospheric turbulence in free-space laser communication. These light-weight, low power deformable mirrors have an active aperture of up to 25.2mm consisting of a thin silicon membrane mirror supported by an array of 140 to 4092 electrostatic actuators which exhibit no hysteresis and have sub-nanometer repeatability making them well suited for open-loop control applications such as Multi-Object Adaptive Optics (MOAO). The continuous membrane deformable mirrors, coated with a highly reflective metal film, are capable of up to 6μm of stroke, have a surface finish of <10nm RMS with a fill factor of 99.8%. Presented in this paper are device characteristics and performance test results, as well as reliability test data and device lifetime predictions that show that trillions of actuator cycles can be achieved without failures.

  15. Nine toes; Mirror Foot Deformity

    PubMed Central

    Vlahovic, Aleksandar M; Pistignjat, Boris S; Vlahovic, Natasa S

    2015-01-01

    Mirror foot is a very rare congenital anomaly, with only a few papers presenting definitive treatment for this entity. There are limited management recommendations. Most cases are treated before walking age. In our case, there were no associated developmental defects of the leg. The child underwent complex rays resection with medial foot reconstruction. After 7.5 years of followup, definitive surgical treatment was performed with satisfactory cosmetic and functional outcome. PMID:26229172

  16. Active Beam Shaping System and Method Using Sequential Deformable Mirrors

    NASA Technical Reports Server (NTRS)

    Norman, Colin A. (Inventor); Pueyo, Laurent A. (Inventor)

    2015-01-01

    An active optical beam shaping system includes a first deformable mirror arranged to at least partially intercept an entrance beam of light and to provide a first reflected beam of light, a second deformable mirror arranged to at least partially intercept the first reflected beam of light from the first deformable mirror and to provide a second reflected beam of light, and a signal processing and control system configured to communicate with the first and second deformable mirrors. The first deformable mirror, the second deformable mirror and the signal processing and control system together provide a large amplitude light modulation range to provide an actively shaped optical beam.

  17. Evaluation of microfabricated deformable mirror systems

    NASA Astrophysics Data System (ADS)

    Cowan, William D.; Lee, Max K.; Bright, Victor M.; Welsh, Byron M.

    1998-09-01

    This paper presents recent result for aberration correction and beam steering experiments using polysilicon surface micromachined piston micromirror arrays. Microfabricated deformable mirrors offer a substantial cost reduction for adaptive optic systems. In addition to the reduced mirror cost, microfabricated mirrors typically require low control voltages, thus eliminating high voltage amplifiers. The greatly reduced cost per channel of adaptive optic systems employing microfabricated deformable mirrors promise high order aberration correction at low cost. Arrays of piston micromirrors with 128 active elements were tested. Mirror elements are on a 203 micrometers 12 by 12 square grid. The overall array size is 2.4 mm square. The arrays were fabricated in the commercially available DARPA supported MUMPs surface micromachining foundry process. The cost per mirror array in this prototyping process is less than 200 dollars. Experimental results are presented for a hybrid correcting element comprised of a lenslet array and piston micromirror array, and for a piston micromirror array only. Also presented is a novel digital deflection micromirror which requires no digital to analog converters, further reducing the cost of adaptive optics system.

  18. Deformable Mirrors Capture Exoplanet Data, Reflect Lasers

    NASA Technical Reports Server (NTRS)

    2014-01-01

    To image and characterize exoplanets, Goddard Space Flight Center turned to deformable mirrors (DMs). Berkeley, California-based Iris AO, Inc. worked with Goddard through the SBIR program to improve the company’s microelectromechanical DMs, which are now being evaluated and used for biological research, industrial applications, and could even be used by drug manufacturers.

  19. Deformable mirror design of Subaru LGSAO system

    NASA Astrophysics Data System (ADS)

    Oya, Shin; Guyon, Olivier; Watanabe, Makoto; Hayano, Yutaka; Takami, Hideki; Iye, Masanori; Arimoto, Nobuo; Colley, Stephen; Eldred, Michael; Kane, Thomas; Hattori, Masayuki; Saito, Yoshihiko; Kamata, Yukiko; Kobayashi, Naoto; Minowa, Yosuke; Goto, Miwa; Takato, Naruhisa

    2004-10-01

    As an upgrade plan of Subaru adaptive optics facility, laser-guide-star adaptive-optics (LGSAO) project is on going. One of key components of the project is a deformable mirror (DM). The DM for LGSAO is a bimorph type of PZT with 188 control elements. The specification of design is presented together with the analysis of stroke and vibration properties by FEM.

  20. Deformable mirror for high power laser applications

    NASA Astrophysics Data System (ADS)

    Mrň; a, Libor; Sarbort, Martin; Hola, Miroslava

    2015-01-01

    The modern trend in high power laser applications such as welding, cutting and surface hardening lies in the use of solid-state lasers. The output beam of these lasers is characterized by a Gaussian intensity distribution. However, the laser beams with different intensity distributions, e.g. top-hat, are preferable in various applications. In this paper we present a new type of deformable mirror suitable for the corresponding laser beam shaping. The deformation of the mirror is achieved by an underlying array of actuators and a pressurized coolant that also provides the necessary cooling. We describe the results of the surface shape measurement using a 3D scanner for different settings of actuators. Further, we show the achieved intensity distributions measured by a beam profiler for a low power laser beam reflected from the mirror.

  1. Lightweight deformable mirrors for future space telescopes

    NASA Astrophysics Data System (ADS)

    Patterson, Keith

    This thesis presents a concept for ultra-lightweight deformable mirrors based on a thin substrate of optical surface quality coated with continuous active piezopolymer layers that provide modes of actuation and shape correction. This concept eliminates any kind of stiff backing structure for the mirror surface and exploits micro-fabrication technologies to provide a tight integration of the active materials into the mirror structure, to avoid actuator print-through effects. Proof-of-concept, 10-cm-diameter mirrors with a low areal density of about 0.5 kg/m2 have been designed, built and tested to measure their shape-correction performance and verify the models used for design. The low cost manufacturing scheme uses replication techniques, and strives for minimizing residual stresses that deviate the optical figure from the master mandrel. It does not require precision tolerancing, is lightweight, and is therefore potentially scalable to larger diameters for use in large, modular space telescopes. Other potential applications for such a laminate could include ground-based mirrors for solar energy collection, adaptive optics for atmospheric turbulence, laser communications, and other shape control applications. The immediate application for these mirrors is for the Autonomous Assembly and Reconfiguration of a Space Telescope (AAReST) mission, which is a university mission under development by Caltech, the University of Surrey, and JPL. The design concept, fabrication methodology, material behaviors and measurements, mirror modeling, mounting and control electronics design, shape control experiments, predictive performance analysis, and remaining challenges are presented herein. The experiments have validated numerical models of the mirror, and the mirror models have been used within a model of the telescope in order to predict the optical performance. A demonstration of this mirror concept, along with other new telescope technologies, is planned to take place during

  2. Thermomechanical characterization of a membrane deformable mirror

    SciTech Connect

    Morse, Kathleen A.; McHugh, Stuart L.; Fixler, Jeff

    2008-10-10

    A membrane deformable mirror has been investigated for its potential use in high-energy laser systems. Experiments were performed in which the deformable mirror was heated with a 1 kW incandescent lamp and the thermal profile, the wavefront aberrations, and the mechanical displacement of the membrane were measured. A finite element model was also developed. The wavefront characterization experiments showed that the wavefront degraded with heating. Above a temperature of 35 deg. C, the wavefront characterization experiments indicated a dramatic increase in the high-order wavefront modes before the optical beam became immeasurable in the sensors. The mechanical displacement data of the membrane mirror showed that during heating, the membrane initially deflected towards the heat source and then deflected away from the heat source. Finite element analysis (FEA) predicted a similar displacement behavior as shown by the mechanical displacement data but over a shorter time scale and a larger magnitude. The mechanical displacement data also showed that the magnitude of membrane displacement increased with the experiments that involved higher temperatures. Above a temperature of 35 deg. C, the displacement data showed that random deflections as a function of time developed and that the magnitude of these deflections increased with increased temperature. We concluded that convection, not captured in the FEA, likely played a dominant role in mirror deformation at temperatures above 35 deg. C.

  3. Dual-use bimorph deformable mirrors

    NASA Astrophysics Data System (ADS)

    Griffith, M. S.; Laycock, L. C.; Bagshaw, J. M.; Rowe, D.

    2005-11-01

    Adaptive Optics (AO) is a critical underpinning technology for future optical countermeasures, laser delivery, target illumination and imaging systems. It measures and compensates for optical distortion caused by transmission through the atmosphere, resulting in the ability to deploy smaller lasers and identify targets at greater ranges. AO is also well established in ground based astronomy, and is finding applications in free space optical communications and ophthalmology. One of the key components in an AO system is the wavefront modifier, which acts on the incoming or outgoing beam to counter the effects of the atmosphere. BAE SYSTEMS ATC is developing multi-element Deformable Bimorph Mirrors (DBMs) for such applications. A traditional bimorph deformable mirror uses a set of edge electrodes outside the active area in order to meet the required boundary conditions for the active aperture. This inflicts a significant penalty in terms of bandwidth, which is inversely proportional to the square of the full mirror diameter. We have devised a number of novel mounting arrangements that reduce dead space and thus provide a much improved trade-off between bandwidth and stroke. These schemes include a novel method for providing vertical displacement at the periphery of the aperture, a method for providing a continuous compliant support underneath the bimorph mirror, and a method for providing a three point support underneath the bimorph. In all three cases, there is no requirement for edge electrodes to provide the boundary conditions, resulting in devices of much higher bandwidth. The target is to broaden the use of these types of mirror beyond the current limits of either low order/low bandwidth, to address the high order, high bandwidth systems required by long range, horizontal path applications. This paper will discuss the different mirror designs, and present experimental results for the most recently assembled mirrors.

  4. Fabrication Methods for Adaptive Deformable Mirrors

    NASA Technical Reports Server (NTRS)

    Toda, Risaku; White, Victor E.; Manohara, Harish; Patterson, Keith D.; Yamamoto, Namiko; Gdoutos, Eleftherios; Steeves, John B.; Daraio, Chiara; Pellegrino, Sergio

    2013-01-01

    Previously, it was difficult to fabricate deformable mirrors made by piezoelectric actuators. This is because numerous actuators need to be precisely assembled to control the surface shape of the mirror. Two approaches have been developed. Both approaches begin by depositing a stack of piezoelectric films and electrodes over a silicon wafer substrate. In the first approach, the silicon wafer is removed initially by plasmabased reactive ion etching (RIE), and non-plasma dry etching with xenon difluoride (XeF2). In the second approach, the actuator film stack is immersed in a liquid such as deionized water. The adhesion between the actuator film stack and the substrate is relatively weak. Simply by seeping liquid between the film and the substrate, the actuator film stack is gently released from the substrate. The deformable mirror contains multiple piezoelectric membrane layers as well as multiple electrode layers (some are patterned and some are unpatterned). At the piezolectric layer, polyvinylidene fluoride (PVDF), or its co-polymer, poly(vinylidene fluoride trifluoroethylene P(VDF-TrFE) is used. The surface of the mirror is coated with a reflective coating. The actuator film stack is fabricated on silicon, or silicon on insulator (SOI) substrate, by repeatedly spin-coating the PVDF or P(VDFTrFE) solution and patterned metal (electrode) deposition. In the first approach, the actuator film stack is prepared on SOI substrate. Then, the thick silicon (typically 500-micron thick and called handle silicon) of the SOI wafer is etched by a deep reactive ion etching process tool (SF6-based plasma etching). This deep RIE stops at the middle SiO2 layer. The middle SiO2 layer is etched by either HF-based wet etching or dry plasma etch. The thin silicon layer (generally called a device layer) of SOI is removed by XeF2 dry etch. This XeF2 etch is very gentle and extremely selective, so the released mirror membrane is not damaged. It is possible to replace SOI with silicon

  5. Electrostatic membrane deformable mirror characterization and applications

    NASA Astrophysics Data System (ADS)

    Bush, Keith; Marrs, Anthony; Schoen, Michael

    2005-08-01

    Electrostatic Membrane Deformable Mirror (MDM) technology developed using silicon bulk micro-machining techniques offers the potential of providing low-cost, compact wavefront control systems for diverse optical system applications. Electrostatic mirror construction using bulk micro-machining allows for custom designs to satisfy wavefront control requirements for most optical systems. An electrostatic MDM consists of a thin membrane, generally with a thin metal or multi-layer high-reflectivity coating, suspended over an actuator pad array that is connected to a high-voltage driver. Voltages applied to the array elements deflect the membrane to provide an optical surface capable of correcting for measured optical aberrations in a given system. Electrostatic membrane DM designs are derived from well-known principles of membrane mechanics and electrostatics, the desired optical wavefront control requirements, and the current limitations of mirror fabrication and actuator drive electronics. MDM performance is strongly dependent on mirror diameter and air damping in meeting desired spatial and temporal frequency requirements. In this paper, we discuss characterization measurements and modeling of MDM spatial and temporal performance for different mirror designs and present application results illustrating the diverse uses of MDM technology in optical wavefront compensation systems.

  6. High resolution lithography-compatible micro-electro-discharge machining of bulk metal foils for micro-electro-mechanical systems

    NASA Astrophysics Data System (ADS)

    Richardson, Mark Thomas

    The application of batch mode micro-electro-discharge machining (microEDM) to the fabrication of micro-electro-mechanical systems has opened the door to lithographically compatible precision machining of all bulk metals. High volume applications in biomedical, communications, and consumer electronics devices are enabled by this technology. This dissertation explores the capabilities, limitations, and further improvement of high density batch mode microEDM. There are four parts to this effort described below. A machining resolution study of high density features in stainless steel identifies the design space. Lithographically fabricated copper tools with single cross, parallel line, and circle/square array features of 5--100microm width and 5--75microm spacing were used. The observed discharge gap varies with shape, spacing, and feature location from 3.8--8microm. As tool feature density is increased, debris accumulation effects begin to dominate, eventually degrading both tool and workpiece. Two new techniques for mitigating this debris build-up are separately investigated. The first is a silicon passivation coating which suppresses spurious discharges triggered from the sidewalls of the machining tool. By this method, for high density batch machining, mean tool wear rate decreases from a typical rate of about 34% to 1.7% and machining non-uniformity reduces from 4.9microm to 1.1microm across the workpiece. The second involves a two-step machining process that enhances the hydraulic removal of machining debris and therefore throughput. Wireless RF signals are inherently emitted by the micro-discharge process. This thesis describes the first reported wireless detection of debris accumulation during microEDM, enabling direct monitoring of machining quality in real time with 5dBm signal drop. The first wireless detection of the interface between two stacked metals during microEDM is also reported giving a 10dBm signal change. The technique enables direct monitoring of

  7. Crack growth phenomena in micro-machined single crystal silicon and design implications for micro electro mechanical systems (MEMS)

    NASA Astrophysics Data System (ADS)

    Fitzgerald, Alissa Mirella

    The creation of micron-sized mechanisms using semiconductor processing technology is known collectively as MEMS, or Micro Electro Mechanical Systems. Many MEMS devices, such as accelerometers and switches, have mechanical structures fabricated from single crystal silicon, a brittle material. The reliability and longevity of these devices depends on minimizing the probability of fracture, and therefore requires a thorough understanding of crack growth phenomena in silicon. In this study, a special micro-machined fracture specimen, the compression-loaded double cantilever beam, was developed to study fracture phenomena in single crystal silicon on a size scale relevant to MEMS. The decreasing stress intensity geometry of this sample provided stable, controllable crack propagation in test sections as thin as 100 mum. Several common MEMS fabrication methods (plasma and chemical etch) were used to achieve a range of surface finishes. A 650 A thick titanium crack gage was used to directly measure crack extension as a function of time using the potential drop technique. High speed (100 MHz) data acquisition techniques were employed to capture fracture events on the sub-microsecond time scale. The stability of the sample design and the micron-scale resolution of the crack gage facilitated investigation into the existence of a stress corrosion effect in silicon. No evidence of sub-critical crack growth due to exposure to humid air was found in carefully controlled tests lasting up to 24 hours. Rapid crack propagation velocities (>1 km/s) during quasi-static loading were recorded using high speed data acquisition techniques. Unique evidence was found of reflected stress waves causing multiple, momentary arrests during rapid fracture events. These measurements, along with atomic force microscope scans of the fracture surfaces, offer new insight into the kinetics of the fracture process in silicon. Over 100 micro-machined samples were fractured in this research. Weibull

  8. A large stroke magnetic fluid deformable mirror for focus control

    NASA Astrophysics Data System (ADS)

    Min, Ling-kun; Wu, Zhi-zheng; Huang, Ming-shuang; Kong, Xiang-hui

    2016-03-01

    A liquid deformable mirror, which can provide a large stroke deflection more than 100 μm, is proposed for focus control. The deformable mirror utilizes the concept of magnetic fluid deformation shaped with electromagnetic fields to achieve concave or convex surface and to change the optical focus depth of the mirrors. The free surface of the magnetic fluid is coated with a thin layer of metal-liquid-like film (MELLF) prepared from densely packed silver nanoparticles to enhance the reflectance of the deformable mirror. The experimental results on the fabricated prototype magnetic fluid deformable mirror (MFDM) show that the desired concave/convex surface shape can be controlled precisely with a closed-loop adaptive optical system.

  9. Analysis of a combined tip-tilt and deformable mirror.

    PubMed

    Wilcox, Christopher C; Andrews, Jonathan R; Restaino, Sergio R; Teare, Scott W; Payne, Don M; Krishna, Sanjay

    2006-03-15

    A deformable mirror mounted on a two-axis tilt platform can provide wavefront compensation at a single location in an adaptive optics system, resulting in a significant reduction in the number of optical components in the system and in a simplification of the alignment. However, the moment of inertia of a deformable mirror is significantly different from that of the monolithic mirror commonly mounted on a tilt platform. We report on what are to our knowledge the first experimental results of mounting a microelectromechanical deformable mirror onto a fast steering platform and the first observation that at low operating frequencies high-order deformation of the deformable mirror membrane was not recorded. PMID:16544588

  10. Dynamic deformation analysis of light-weight mirror

    NASA Astrophysics Data System (ADS)

    Zhang, Yingtao; Cao, Xuedong; Kuang, Long; Yang, Wei

    2012-10-01

    In the process of optical dynamic target work, under the effort of the arm of dynamic target, the mirror needs to do circular motion, additional accelerated motion and uniform motion. The maximum acceleration is 10°/s2 and the maximum velocity is 30°/s. In this paper, we mostly analyze the dynamic deformation of a 600 mm honeycomb light-weight mirror of a certain dynamic target. Using the FEA (finite element analysis) method, first of all, we analyze the deformation of the light-weight mirror induced in gravity at different position; later, the dynamic deformation of light-weight mirror is analyzed in detailed. The analysis results indicate that, when the maximum acceleration is 10°/s2 and the maximum velocity is 30°/s, the centripetal force is 5% of the gravity at the equal mass, and the dynamic deformation of the mirror is 6.1% of the deformation induced by gravity.

  11. Multi-physics simulation and fabrication of a compact 128 × 128 micro-electro-mechanical system Fabry-Perot cavity tunable filter array for infrared hyperspectral imager.

    PubMed

    Meng, Qinghua; Chen, Sihai; Lai, Jianjun; Huang, Ying; Sun, Zhenjun

    2015-08-01

    This paper demonstrates the design and fabrication of a 128×128 micro-electro-mechanical systems Fabry-Perot (F-P) cavity filter array, which can be applied for the hyperspectral imager. To obtain better mechanical performance of the filters, F-P cavity supporting structures are analyzed by multi-physics finite element modeling. The simulation results indicate that Z-arm is the key component of the structure. The F-P cavity array with Z-arm structures was also fabricated. The experimental results show excellent parallelism of the bridge deck, which agree with the simulation results. A conclusion is drawn that Z-arm supporting structures are important to hyperspectral imaging system, which can achieve a large tuning range and high fill factor compared to straight arm structures. The filter arrays have the potential to replace the traditional dispersive element. PMID:26368101

  12. Biological application of micro-electro mechanical systems microelectrode array sensors for direct measurement of phosphate in the enhanced biological phosphorous removal process.

    PubMed

    Lee, Woo Hyoung; Lee, Jin-Hwan; Bishop, Paul L; Papautsky, Ian

    2009-08-01

    The determination of phosphate has been of great importance in the fields of clinical, environmental, and horticultural analysis for over three decades. New cobalt-based micro-electro mechanical systems (MEMS) microelectrode array (MEA) sensors for direct measurement of phosphate in small environmental samples, such as microbial aggregates, has been introduced and applied here for in situ measurement of phosphate within activated sludge flocs in the enhanced biological phosphorus removal process. The MEMS technologies offer the advantages of accurate fabrication methods, reduced complexity of the fabrication process, mass production, low cost, and increased reliability. Well-defined phosphate profiles across the flocs were observed under anaerobic conditions, during which, phosphate was released from the flocs, using the MEMS MEA sensor. The microprofiles were compared with the microprofiles measured using conventional phosphate microelectrodes. The developed MEMS MEA sensors were useful tools for the in situ measurement of phosphate in small aggregates. PMID:19774851

  13. Overview of deformable mirror technologies for adaptive optics and astronomy

    NASA Astrophysics Data System (ADS)

    Madec, P.-Y.

    2012-07-01

    From the ardent bucklers used during the Syracuse battle to set fire to Romans’ ships to more contemporary piezoelectric deformable mirrors widely used in astronomy, from very large voice coil deformable mirrors considered in future Extremely Large Telescopes to very small and compact ones embedded in Multi Object Adaptive Optics systems, this paper aims at giving an overview of Deformable Mirror technology for Adaptive Optics and Astronomy. First the main drivers for the design of Deformable Mirrors are recalled, not only related to atmospheric aberration compensation but also to environmental conditions or mechanical constraints. Then the different technologies available today for the manufacturing of Deformable Mirrors will be described, pros and cons analyzed. A review of the Companies and Institutes with capabilities in delivering Deformable Mirrors to astronomers will be presented, as well as lessons learned from the past 25 years of technological development and operation on sky. In conclusion, perspective will be tentatively drawn for what regards the future of Deformable Mirror technology for Astronomy.

  14. A deformable secondary mirror for the VLT

    NASA Astrophysics Data System (ADS)

    Arsenault, R.; Biasi, R.; Gallieni, D.; Riccardi, A.; Lazzarini, P.; Hubin, N.; Fedrigo, E.; Donaldson, R.; Oberti, S.; Stroebele, S.; Conzelmann, R.; Duchateau, M.

    2006-06-01

    ESO has initiated in June 2004 a feasibility study to investigate the possibility to retro-fit one of the VLT 8 m telescope with a deformable secondary mirror (DSM). The scope of this effort has been broadened to a concept of Adaptive Optics Facility (adaptive telescope with adapted instrument park). The feasibility study, conducted by MicroGate, ADS Intl and the INAF-Osservatorio Astrofisico di Arcetri, has been successful (no show stopper identified) and has provided an elegant design of an alternate M2-Unit for the VLT. It features a 1170 actuators DSM based on the voice coil force actuators coupled with capacitive sensors. An 80 kHz internal control loop allows implementing of electronic damping. The simulations performed have shown a fitting error of 62.5 nm rms (r ° = 12.1 cm @ 30 deg. zenith) with a 2mm thin shell and 1.5 kW of heat dissipation. The design shall provide a full stroke of ~50 μm and a rise time of < 1 msec. The DSM will be focused and "centered" by a Hexapod and a bi-positions electro-mechanism will allow switching from Nasmyth to Cassegrain focus configuration. Several features are planned to ease maintenance and diagnostic.

  15. Structure modulated electrostatic deformable mirror for focus and geometry control.

    PubMed

    Nam, Saekwang; Park, Suntak; Yun, Sungryul; Park, Bongje; Park, Seung Koo; Kyung, Ki-Uk

    2016-01-11

    We suggest a way to electrostatically control deformed geometry of an electrostatic deformable mirror (EDM) based on geometric modulation of a basement. The EDM is composed of a metal coated elastomeric membrane (active mirror) and a polymeric basement with electrode (ground). When an electrical voltage is applied across the components, the active mirror deforms toward the stationary basement responding to electrostatic attraction force in an air gap. Since the differentiated gap distance can induce change in electrostatic force distribution between the active mirror and the basement, the EDMs are capable of controlling deformed geometry of the active mirror with different basement structures (concave, flat, and protrusive). The modulation of the deformed geometry leads to significant change in the range of the focal length of the EDMs. Even under dynamic operations, the EDM shows fairly consistent and large deformation enough to change focal length in a wide frequency range (1~175 Hz). The geometric modulation of the active mirror with dynamic focus tunability can allow the EDM to be an active mirror lens for optical zoom devices as well as an optical component controlling field of view. PMID:26832237

  16. Correction of an active space telescope mirror using a gradient approach and an additional deformable mirror

    NASA Astrophysics Data System (ADS)

    Allen, Matthew R.; Kim, Jae Jun; Agrawal, Brij N.

    2015-09-01

    High development cost is a challenge for space telescopes and imaging satellites. One of the primary reasons for this high cost is the development of the primary mirror, which must meet diffraction limit surface figure requirements. Recent efforts to develop lower cost, lightweight, replicable primary mirrors include development of silicon carbide actuated hybrid mirrors and carbon fiber mirrors. The silicon carbide actuated hybrid mirrors at the Naval Postgraduate School do not meet the surface quality required for an optical telescope due to high spatial frequency residual surface errors. A technique under investigation at the Naval Postgraduate School is to correct the residual surface figure error using a deformable mirror in the optical path. We present a closed loop feedback gradient controller to actively control a SMT active segment and an additional deformable mirror to reduce residual wavefront error. The simulations and experimental results show that the gradient controller reduces the residual wavefront error more than an integral controller.

  17. An image stabilization optical system using deformable freeform mirrors.

    PubMed

    Hao, Qun; Cheng, Xuemin; Kang, Jiqiang; Jiang, Yuhua

    2015-01-01

    An image stabilization optical system using deformable freeform mirrors is proposed that enables the ray sets to couple dynamically in the object and image space. It aims to correct image blurring and degradation when there is relative movement between the imaging optical axis and the object. In this method, Fermat's principle and matrix methods are used to describe the optical path of the entire optical system with a shift object plane and a fixed corresponding image plane in the carrier coordinate system. A constant optical path length is determined for each ray set, so the correspondence between the object and the shift free image point is used to calculate the solution to the points on the surface profile of the deformable mirrors (DMs). Off-axis three-mirror anastigmats are used to demonstrate the benefits of optical image stabilization with one- and two-deformable mirrors. PMID:25599423

  18. An Image Stabilization Optical System Using Deformable Freeform Mirrors

    PubMed Central

    Hao, Qun; Cheng, Xuemin; Kang, Jiqiang; Jiang, Yuhua

    2015-01-01

    An image stabilization optical system using deformable freeform mirrors is proposed that enables the ray sets to couple dynamically in the object and image space. It aims to correct image blurring and degradation when there is relative movement between the imaging optical axis and the object. In this method, Fermat's principle and matrix methods are used to describe the optical path of the entire optical system with a shift object plane and a fixed corresponding image plane in the carrier coordinate system. A constant optical path length is determined for each ray set, so the correspondence between the object and the shift free image point is used to calculate the solution to the points on the surface profile of the deformable mirrors (DMs). Off-axis three-mirror anastigmats are used to demonstrate the benefits of optical image stabilization with one- and two-deformable mirrors. PMID:25599423

  19. In-situ Iberian pig carcass classification using a micro-electro-mechanical system (MEMS)-based near infrared (NIR) spectrometer.

    PubMed

    Zamora-Rojas, E; Pérez-Marín, D; De Pedro-Sanz, E; Guerrero-Ginel, J E; Garrido-Varo, A

    2012-03-01

    Iberian pig (IP) products are gourmet foods highly appreciated at international markets, reaching high prices, because of its exquisite flavors. At present, there aren't practical and affordable analytical methods which can authenticate every single piece put on the market. This paper reports on the performance of a handheld micro-electro-mechanical system (MEMS)-based spectrometer (1600-2400nm) for authentication-classification of individual IP carcasses into different commercial categories. Performance (accuracy and instrumental design) of the instrument was compared with that of high-resolution NIRS monochromators (400-2500nm). A total of 300 carcasses of IPs raised under different feeding regimes ("Acorn", "Recebo" and "Feed") were analyzed in three modes (intact fat in the carcass, skin-free subcutaneous fat samples and melted fat samples). The best classification results for the MEMS instrument were: 93.9% "Acorn" carcasses correctly classified, 96.4% "Feed" and 60.6% "Recebo", respectively. Evaluation of model performance confirmed the suitability of the handheld device for individual, fast, non-destructive, low-cost analysis of IP carcasses on the slaughterhouse line. PMID:22075264

  20. Functional Micro-Dispensers based on Micro-Electro-Mechanical-Systems (MEMS) integrated with fabrics as functional materials to protect humans from mosquito feeding.

    PubMed

    Bernier, Ulrich R; Gurman, Pablo; Clark, Gary G; Elman, Noel

    2015-12-28

    Functional Micro-Dispensers (FMDs) based on Micro-Electro-Mechanical-Systems (MEMS) were designed to deliver spatial repellents that reduce the ability of mosquitoes to feed on humans. FMDs were integrated with fabrics as functional materials for protection against mosquito bites. The use of MEMS devices provides an unprecedented control over the release kinetics by means of integration with electronics for selective and timely activation of each device to perform controlled release of pesticides in air. In addition, because MEMS manufacturing techniques evolved from the microelectronic industry, FMDs can be mass produced at very low cost. Trials using FMDs that contained transfluthrin improved protection against mosquito feeding in human subjects above that of permethrin-treated uniform fabric worn on the arm of the volunteer. The overall reduction in feeding was approximately 90% compared to the untreated fabric control, and about 50% reduction compared to the permethrin-treated fabric control. The devices were efficacious over course of 32 days. FMDs have the potential for a simple and cost-effective implementation for mass adoption as wearable devices integrated in fabrics as active functional materials. PMID:26415856

  1. Unimorph deformable mirror for space telescopes: design and manufacturing.

    PubMed

    Rausch, Peter; Verpoort, Sven; Wittrock, Ulrich

    2015-07-27

    Large space telescopes made of deployable and lightweight structures suffer from aberrations caused by thermal deformations, gravitational release, and alignment errors which occur during the deployment procedure. An active optics system would allow on-site correction of wave-front errors, and ease the requirements on thermal and mechanical stability of the optical train. In the course of a project funded by the European Space Agency we have developed and manufactured a unimorph deformable mirror based on piezoelectric actuation. The mirror is able to work in space environment and is designed to correct for large aberrations of low order with high surface fidelity. This paper discusses design, manufacturing and performance results of the deformable mirror. PMID:26367605

  2. MEMS Deformable Mirrors for Adaptive Optics in Astronomical Imaging

    NASA Astrophysics Data System (ADS)

    Cornelissen, S.; Bierden, P. A.; Bifano, T.

    We report on the development of micro-electromechanical (MEMS) deformable mirrors designed for ground and space-based astronomical instruments intended for imaging extra-solar planets. Three different deformable mirror designs, a 1024 element continuous membrane (32x32), a 4096 element continuous membrane (64x64), and a 331 hexagonal segmented tip-tilt-piston are being produced for the Planet Imaging Concept Testbed Using a Rocket Experiment (PICTURE) program, the Gemini Planet Imaging Instrument, and the visible nulling coronograph developed at JPL for NASA's TPF mission, respectively. The design of these polysilicon, surface-micromachined MEMS deformable mirrors builds on technology that was pioneered at Boston University and has been used extensively to correct for ocular aberrations in retinal imaging systems and for compensation of atmospheric turbulence in free-space laser communication. These light-weight, low power deformable mirrors will have an active aperture of up to 25.2mm consisting of thin silicon membrane mirror supported by an array of 1024 to 4096 electrostatic actuators exhibiting no hysteresis and sub-nanometer repeatability. The continuous membrane deformable mirrors, coated with a highly reflective metal film, will be capable of up to 4μm of stroke, have a surface finish of <10nm RMS with a fill factor of 99.8%. The segmented device will have a range of motion of 1um of piston and a 600 arc-seconds of tip/tilt simultaneously and a surface finish of 1nm RMS. The individual mirror elements in this unique device, are designed such that they will maintain their flatness throughout the range of travel. New design features and fabrication processes are combined with a proven device architecture to achieve the desired performance and high reliability. Presented in this paper are device characteristic and performance results of these devices.

  3. Unimorph deformable mirror for space telescopes: environmental testing.

    PubMed

    Rausch, Peter; Verpoort, Sven; Wittrock, Ulrich

    2016-01-25

    We have developed and manufactured a unimorph deformable mirror for space telescopes based on piezoelectric actuation. The mirror features 44 actuators, has an aperture of 50 mm, and is designed to reproduce low-order Zernike modes with a stroke of several tens of μm. We assessed the space compliance by operating the mirror in thermal vacuum, and exposing it to random and sinusoidal vibrations, as well as to ionizing irradiation. Additionally, the operational life time and the laser power handling capability were tested. The mirror was successfully operated in thermal vacuum at 100 K. We report on the conducted tests and the methods used to evaluate the mirror's performance, and discuss the compliance with the demanded requirements. PMID:26832532

  4. Plastic Deformation in Profile-Coated Elliptical KB Mirrors

    DOE PAGESBeta

    Liu, Chian; Conley, R.; Qian, J.; Kewish, C. M.; Liu, W.; Assoufid, L.; Macrander, A. T.; Ice, G. E.; Tischler, J. Z.

    2012-01-01

    Profile coating has been successfully applied to produce elliptical Kirkpatrick-Baez (KB) mirrors using both cylindrical and flat Si substrates. Previously, focusing widths of 70 nm with 15-keV monochromatic and 80 nm with white beam were achieved using a flat Si substrate. Now, precision elliptical KB mirrors with sub-nm figure errors are produced with both Au and Pt coatings on flat substrates. Recent studies of bare Si-, Au-, and Pt-coated KB mirrors under prolonged synchrotron X-ray radiation and low-temperature vacuum annealing will be discussed in terms of film stress relaxation and Si plastic deformation.

  5. Plastic deformation in profile-coated elliptical KB mirrors

    SciTech Connect

    Liu, Chian; Conley, R.; Qian, J; Kewish, C. M.; Liu, Wenjun; Assoufid, Lahsen; Macrander, Albert T.; Ice, Gene E; Tischler, Jonathan

    2012-01-01

    Profile coating has been successfully applied to produce elliptical Kirkpatrick-Baez (KB) mirrors using both cylindrical and flat Si substrates. Previously, focusing widths of 70 nm with 15-keV monochromatic and 80 nm with white beam were achieved using a flat Si substrate. Now precision elliptical KB mirrors with sub-nm figure errors are produced with both Au and Pt coatings on flat substrates. Recent studies of bare Si, Au-, and Pt-coated KB mirrors under prolonged synchrotron x-ray radiation and low-temperature vacuum annealing will be discussed in terms of film-stress relaxation and Si plastic deformation.

  6. Adaptive optics ophthalmologic systems using dual deformable mirrors

    SciTech Connect

    Jones, S; Olivier, S; Chen, D; Sadda, S; Joeres, S; Zawadzki, R; Werner, J S; Miller, D

    2007-02-01

    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.

  7. Actuation of Deformable Mirrors Using Laser Controlled Pistons

    NASA Technical Reports Server (NTRS)

    Scott, Charles E.

    2005-01-01

    Current deformable mirrors used for adaptive optics employ many actuators to adjust the mirror in order to compensate for optical irregularities. These mechanical actuators, which can number in the hundreds for a given mirror, require a significant amount of electrical wires in order to be controlled. The objective of this research is to implement a different type of actuator that can be controlled without the use of wires. The actuator developed employs a laser to quickly heat and expand the air in a closed "cell." When the air expands, it pushes a membrane that causes the mirror to move. Creating an array of these cells, and scanning them with a laser can control a deformable mirror. Testing showed that a single cell with a 5-mm diameter and 10-mm length can deflect a membrane of aluminized mylar in excess of our minimum requirement of 20 microns. These cells can now be assembled in a 5x5 matrix and attached to many small Mirrors. An electro-mechanical scanning assembly can be used to aim the laser directly onto individual cells causing the mirror at that location to move.

  8. Actuation of Deformable Mirrors Using Laser Controlled Pistons

    NASA Technical Reports Server (NTRS)

    Scott, Charles

    2005-01-01

    Current deformable mirrors used for adaptive optics employ many actuators to adjust the mirror in order to compensate for optical irregularities. These mechanical actuators, which can number in the hundreds for a given mirror, require a significant amount of electrical wires in order to be controlled. The objective of this research is to implement a different type of actuator that can be controlled without the use of wires. The actuator developed employs a laser to quickly heat and expand the air in a closed 'cell'. When the air expands, it pushes a membrane that causes the mirror to move. Creating an array of these cells, and scanning them with a laser can control a deformable mirror. Testing showed that a single cell with a 5 mm diameter and 10 mm in length can deflect a membrane of aluminized Mylar in excess of our minimum requirement of 20 microns. These cells can now be assembled in a 5 x 5 matrix and attached to many small mirrors. An electro-mechanical scanning assembly can be used to aim the laser directly onto individual cells causing the mirror at that location to move.

  9. Ferrofluid based deformable mirrors: a new approach to adaptive optics using liquid mirrors

    NASA Astrophysics Data System (ADS)

    Laird, Phil R.; Bergamasco, R.; Bérubé, Vincent; Borra, Ermanno F.; Gingras, Julie; Ritcey, Anna-Marie R.; Rioux, Myriam; Robitaille, Nathalie; Thibault, Simon; Vieira da Silva, L., Jr.; Yockell-Lelièvre, Helene

    2003-02-01

    The trend towards ever larger telescopes and more advanced adaptive optics systems is driving the need for deformable mirrors with a large number of low cost actuators. Liquid mirrors have long been recognized a potential low cost alternative to conventional solid mirrors. By using a water or oil based ferrofluid we are able to benefit from a stronger magnetic response than is found in magnetic liquid metal amalgams and avoid the difficulty of passing a uniform current through a liquid. Depositing a thin silver colloid known as a metal liquid like film (MELLF) on the ferrofluid surface solves the problem of low reflectivity of pure ferrofluids. This combination provides a liquid optical surface that can be precisely shaped in a magnetic field. We present experimental results obtained with a prototype deformable liquid mirror based on this combination.

  10. Numerical simulation of deformation and figure quality of precise mirror

    NASA Astrophysics Data System (ADS)

    Vit, Tomáš; Melich, Radek; Sandri, Paolo

    2015-01-01

    The presented paper shows results and a comparison of FEM numerical simulations and optical tests of the assembly of a precise Zerodur mirror with a mounting structure for space applications. It also shows how the curing of adhesive film can impact the optical surface, especially as regards deformations. Finally, the paper shows the results of the figure quality analysis, which are based on data from FEM simulation of optical surface deformations.

  11. Experimental and simulation study of undesirable short-period deformation in piezoelectric deformable x-ray mirrors

    NASA Astrophysics Data System (ADS)

    Nakamori, Hiroki; Matsuyama, Satoshi; Imai, Shota; Kimura, Takashi; Sano, Yasuhisa; Kohmura, Yoshiki; Tamasaku, Kenji; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto

    2012-05-01

    To construct adaptive x-ray focusing optics whose optical parameters can be varied while performing wavefront correction, ultraprecise piezoelectric deformable mirrors have been developed. We computationally and experimentally investigated undesirable short-period deformation caused by piezoelectric actuators adhered to the substrate during mirror deformation. Based on the results of finite element method analysis, shape measurements, and the observation of x-ray reflection images, a guideline is developed for designing deformable mirrors that do not have short-period deformation errors.

  12. Progress on the development of a zonal bimorph deformable mirror

    NASA Astrophysics Data System (ADS)

    Griffith, Mike S.; Laycock, Leslie C.; Archer, Nick; Myers, Richard; Doel, Peter; Birch, Rolf

    2008-07-01

    The Zonal Bimorph Deformable Mirror (ZBDM) is a new concept of adaptive mirror. It exploits the benefits normally associated with bimorph mirrors, namely simple rugged construction, low capacitance, and cost effectiveness, but in a significant departure from classical, edge supported bimorphs each element is supported from underneath. This results in a localised (zonal) response and enables the device to be scalable up to large aperture, multi-1000 element devices. Crucially, the combination of continuous support coupled with the use of flexi-circuit interconnect promotes the assembly of a high density 'tweeter' deformable mirror (DM) onto a lower density, high dynamic range 'woofer' DM to generate an integrated, dual-stage deformable mirror which can deliver both high resolution and high dynamic range simultaneously. Such a device has the potential to significantly simplify the design of astronomical adaptive optics (AO) systems. We present the progress made on the development of the ZBDM as part of a collaborative project funded by the newly formed UK Science and Technology Facilities Council.

  13. Polymer-based micro deformable mirror for adaptive optics applications

    NASA Astrophysics Data System (ADS)

    Zamkotsian, Frederic; Conedera, Veronique; Liotard, Arnaud; Schroeder, Andreas; Fabre, Norbert; Camon, Henri; Lanzoni, Patrick

    2005-01-01

    Next generation giant telescopes as well as next generation instrumentation for 10m-class telescopes relies on the availability of highly performing adaptive optical systems, for studying new fields like circumstellar disks and extrasolar planets. These systems require deformable mirrors with very challenging parameters, including number of actuators up to 250 000 and inter-actuator spacing around 500μm. MOEMS-based devices are promising for future deformable mirrors. However, only limited strokes for large driving voltages have been demonstrated. In order to overcome these limitations, we are currently developing a micro-deformable mirror based on an array of electrostatic actuators with attachment posts to a continuous mirror on top. The originality of our approach lies in the elaboration of a sacrificial layer and of a structural layer made of polymer materials, using low-temperature process. This process allows the realization of high optical quality mirrors on top of an actuator array made with various techniques. We have developed the first polymer piston-motion actuator in order to reach high strokes for low driving voltages: a 10μm thick mobile plate with four springs attached to the substrate, and with an air gap of 10μm exhibits a piston motion of 2μm for 30V. Preliminary comparison with FEM models show very good agreement and design of a complete polymer-based MDM looks possible.

  14. Deformable mirror interferometric analysis for the direct imagery of exoplanets

    NASA Astrophysics Data System (ADS)

    Mazoyer, Johan; Galicher, Raphaël.; Baudoz, Pierre; Lanzoni, Patrick; Zamkotsian, Frédéric; Rousset, Gérard

    2014-07-01

    Direct imaging of exoplanet systems requires the use of coronagraphs to reach high contrast levels (10-8 to 10-11) at small angular separations (0.100). However, the performance of these devices is drastically limited by aberrations (in phase or in amplitude, introduced either by atmosphere or by the optics). Coronagraphs must therefore be combined with extreme adaptive optic systems, composed of a focal plane wavefront sensor and of a high order deformable mirror. These adaptive optic systems must reach a residual error in the corrected wavefront of less than 0.1 nm (RMS) with a rate of 1 kHz. In addition, the surface defects of the deformable mirror, inherent from the fabrication process, must be limited in order to avoid the introduction of amplitude aberrations. An experimental high contrast bench has been developed at the Paris Observatory (LESIA). This bench includes a Boston Micromachine deformable mirror composed of 1024 actuators. For a precise analysis of its surface and performance, we characterized this mirror on the interferometric bench developed since 2004 at the Marseille Observatory (LAM). In this paper, we present this interferometric bench as well as the results of the analysis. This will include a precise surface characterization and a description of the behavior of the actuators, on a 10 by 10 actuator range (behavior of a single actuator, study of the cross-talk between neighbor actuators, influence of a stuck actuator) and on full mirror scale (general surface shape).

  15. Micro electro-mechanical heater

    DOEpatents

    Oh, Yunje; Asif, Syed Amanulla Syed; Cyrankowski, Edward; Warren, Oden Lee

    2016-04-19

    A sub-micron scale property testing apparatus including a test subject holder and heating assembly. The assembly includes a holder base configured to couple with a sub-micron mechanical testing instrument and electro-mechanical transducer assembly. The assembly further includes a test subject stage coupled with the holder base. The test subject stage is thermally isolated from the holder base. The test subject stage includes a stage subject surface configured to receive a test subject, and a stage plate bracing the stage subject surface. The stage plate is under the stage subject surface. The test subject stage further includes a heating element adjacent to the stage subject surface, the heating element is configured to generate heat at the stage subject surface.

  16. Surface Slope Metrology on Deformable Soft X-ray Mirrors

    SciTech Connect

    Yuan, Sheng; Yashchuk, Valeriy V.; Goldberg, Kenneth A.; Celestre, Rich; Church, Matthew; McKinney, Wayne R.; Morrison, Greg; Warwick, Tony

    2010-01-31

    We report on the current state of surface slope metrology on deformable mirrors for soft x-rays at the Advanced Light Source (ALS). While we are developing techniques for in situ at-wavelength tuning, we are refining methods of ex situ visible-light optical metrology to achieve sub-100-nrad accuracy. This paper reports on laboratory studies, measurements and tuning of a deformable test-KB mirror prior to its use. The test mirror was bent to a much different optical configuration than its original design, achieving a 0.38 micro-radian residual slope error. Modeling shows that in some cases, by including the image conjugate distance as an additional free parameter in the alignment, along with the two force couples, fourth-order tangential shape errors (the so-called bird shape) can be reduced or eliminated.

  17. Surface Slope Metrology on Deformable Soft X-ray Mirrors

    SciTech Connect

    Yuan, S.; Yashchuk, V.V.; Goldberg, K.A.; Celestre, R.; Church, M.; McKinney, W.R.; Morrison, G.; Warwick, T.

    2009-09-18

    We report on the current state of surface slope metrology on deformable mirrors for soft x-rays at the Advanced Light Source (ALS). While we are developing techniques for in situ at-wavelength tuning, we are refining methods of ex situvisible-light optical metrology to achieve sub-100-nrad accuracy. This paper reports on laboratory studies, measurements and tuning of a deformable test-KB mirror prior to its use. The test mirror was bent to a much different optical configuration than its original design, achieving a 0.38 micro-radian residual slope error. Modeling shows that in some cases, by including the image conjugate distance as an additional free parameter in the alignment, along with the two force couples, fourth-order tangential shape errors (the so-called bird shape) can be reduced or eliminated.

  18. Simple unimorph deformable mirrors fabricated from piezo buzzers

    NASA Astrophysics Data System (ADS)

    Pribošek, Jaka; Diaci, Janez; Sinzinger, Stefan

    2016-05-01

    This study shows how unimorph deformable mirrors can be effectively fabricated out of commercially available piezo-buzzers without any high-tech equipment. Our design involves a quad-channel mirror with monolithically integrated flexures. The mirror is controlled by a custom quad-channel high-voltage driver unit, capable of 93 Vp-p and 75 kpps performance. The system exhibits 16-bit resolution over the angular working range of  ±1.85 mrad, with 0.04 mrad V‑1 angular sensitivity and 14% hysteresis. We demonstrate the mirror performance for focus control in microscopy and high-precision laser beam steering, opening a wide variety of applications in computational imaging, confocal microscopy, optical tweezing and laser lithography.

  19. Contactless Large Deformable Mirrors: ELT AO corrector technology available now

    NASA Astrophysics Data System (ADS)

    Biasi, Roberto; Gallieni, Daniele

    2011-09-01

    We present our design of ESO E-ELT M4 deformable mirror and GMT Adaptive Secondary Mirrors unit. Both systems are based on our consolidated design of large deformable mirrors for 8-m class telescopes, successfully implemented on MMT and LBT and currently in advanced construction and testing phase for VLT and Magellan telescopes respectively. We describe the main features of the technology adopted: thin Zerodur mirror shell with contactless voice coil motors, co-located capacitive sensors to close a local position loop at each actuator, centralized control by force feedforward, embedded real time control and communication electronics. We then highlight how the same concept has been scaled up on the E-ELT M4AU and the GMT-ASM cases, adapting the technology to deal with thousands of actuators, while maintaining its intrinsic advantages: tolerance to actuators' failures, mechanical de-coupling and relaxed tolerances between correcting mirror and reference structure, large stroke, hysteresis-free behavior. For the next generation systems, we report the predicted performances based on the actual results attained on our 1-m class DMs currently in use: the LBT adaptive secondary for the GMT-ASM and the 330 actuators Demonstration Prototype for the E-ELT M4AU.

  20. HIGH-CONTRAST IMAGING VIA MODAL CONVERGENCE OF DEFORMABLE MIRROR

    SciTech Connect

    Wang Feiling

    2012-06-01

    For extremely high contrast imaging, such as direct observation of faint stellar companions, an adaptive optics system is required to produce low-halo and low-speckle regions in the focal plane. A method for deformable mirror control is proposed to achieve this goal. The method relies on a modal convergence of the deformable mirror driven by a focal-plane metric. The modal sets are derived from the Walsh functions. The Walsh-function modes serve two purposes: the expansion of the actuator displacements and the expansion of the phase functions. Taking advantage of the unique properties of the modal functions, a universal control algorithm is devised for the realization of high-contrast focal planes with and without the help of conventional coronagraphy. Numerical modeling is conducted to simulate complete imaging systems under various scenarios. It is shown that the proposed method reliably produces high-contrast focal planes using either a segmented or a membrane mirror. In the presence of random aberration the method is shown to be able to maintain high-contrast focal planes. Requiring neither retrieval of electric fields nor detailed knowledge of the deformable mirrors, this technique may allow high-contrast imaging in real time.

  1. Effects of alloying and local order in AuNi contacts for Ohmic radio frequency micro electro mechanical systems switches via multi-scale simulation

    NASA Astrophysics Data System (ADS)

    Gaddy, Benjamin E.; Kingon, Angus I.; Irving, Douglas L.

    2013-05-01

    Ohmic RF-MEMS switches hold much promise for low power wireless communication, but long-term degradation currently plagues their reliable use. Failure in these devices occurs at the contact and is complicated by the fact that the same asperities that bear the mechanical load are also important to the flow of electrical current needed for signal processing. Materials selection holds the key to overcoming the barriers that prevent widespread use. Current efforts in materials selection have been based on the material's (or alloy's) ability to resist oxidation as well as its room-temperature properties, such as hardness and electrical conductivity. No ideal solution has yet been found via this route. This may be due, in part, to the fact that the in-use changes to the local environment of the asperity are not included in the selection criteria. For example, Joule heating would be expected to raise the local temperature of the asperity and impose a non-equilibrium thermal gradient in the same region expected to respond to mechanical actuation. We propose that these conditions should be considered in the selection process, as they would be expected to alter mechanical, electrical, and chemical mechanisms in the vicinity of the surface. To this end, we simulate the actuation of an Ohmic radio frequency micro electro mechanical systems switch by using a multi-scale method to model a current-carrying asperity in contact with a polycrystalline substrate. Our method couples continuum solutions of electrical and thermal transport equations to an underlying molecular dynamics simulation. We present simulations of gold-nickel asperities and substrates in order to evaluate the influence of alloying and local order on the early stages of contact actuation. The room temperature response of these materials is compared to the response of the material when a voltage is applied. Au-Ni interactions are accounted for through modification of the existing Zhou embedded atom method

  2. Lightweight in-plane actuated deformable mirrors for space telescopes

    NASA Astrophysics Data System (ADS)

    Shepherd, Michael J.

    This research focused on lightweight, in-plane actuated, deformable mirrors, with the ultimate goal of developing a 20-meter or larger diameter light gathering aperture for space telescopes. Membrane optics is the study of these structures which may be stowed compactly and unfurled in orbit. This effort comprised four research areas: modelling, analytical solutions, surface control strategy, and scaling. Initially, experimental results were compared to theory using a 0.127 meter diameter deformable mirror testbed. The mirror was modelled using finite elements with MSC.Nastran software, where a boundary tension field was determined using laser vibrometer data. A non-linear solution technique was used to incorporate the membrane stiffening from the applied tension. Statically obtained actuator influence functions were compared to experimentally achieved data, and then a least squares approach was used as the basis for creating a quasi-static control algorithm. Experimental simultaneous tracking of Zernike tip, tilt, and defocus modes was successfully demonstrated. The analytical solutions to plate-membrane and beam-string ordinary differential equation representing the deformable mirror equations were developed. A simplified approach to modelling the axisymmetric cases was also presented. Significantly, it was shown both analytically and through numerical analysis that static actuation for a mirror with a discrete electrode pattern and a high tension-to-stiffness ratio was simply a localized piston displacement in the region of the actuator. Next, a novel static control strategy, the Modal Transformation Method, was developed for membrane mirrors. The method was implemented in finite element simulation, and shows the capability of the in-plane actuated mirror to form Zernike surfaces within an interior, or clear aperture, region using a number of statically-actuated structural modes. Lastly, the scaling problem for membrane optics was addressed. Linear modelling was

  3. A technique for the optical analysis of deformed telescope mirrors

    NASA Technical Reports Server (NTRS)

    Bolton, John F.

    1986-01-01

    The NASTRAN-ACCOS V programs' interface merges structural and optical analysis capabilities in order to characterize the performance of the NASA Goddard Space Flight Center's Solar Optical Telescope primary mirror, which has a large diameter/thickness ratio. The first step in the optical analysis is to use NASTRAN's FEM to model the primary mirror, simulating any distortions due to gravitation, thermal gradients, and coefficient of thermal expansion nonuniformities. NASTRAN outputs are then converted into an ACCOS V-acceptable form; ACCOS V generates the deformed optical surface on the basis of these inputs, and imaging qualities can be determined.

  4. Modal dynamics of magnetic-liquid deformable mirrors.

    PubMed

    Brousseau, Denis; Thibault, Simon; Borra, Ermanno F; Boivin, Simon F

    2014-08-01

    Magnetic-liquid deformable mirrors (MLDMs) were introduced by our group in 2004 and numerous developments have been made since then. The usefulness of this type of mirror in various applications has already been shown, but experimental data on their dynamics are still lacking. A complete theoretical modeling of MLDM dynamics is a complex task because it requires an approach based on magnetohydrodynamics. A purpose of this paper is to present and analyze new experimental data of the dynamics of these mirrors from open-loop step response measurements and show that a basic transfer function modeling is adequate to achieve closed-loop control. Also, experimental data on the eigenmodes dynamic is presented and a modal-based control approach is suggested. PMID:25090320

  5. Deformable mirror with combined piezoelectric and electrostatic actuators

    NASA Astrophysics Data System (ADS)

    Merkle, F.; Freischlad, K.; Reischmann, H.-L.

    1982-10-01

    An adaptive optics system with modal phase correction for reconstituting astronomical images passing through the atmosphere is described. An active mirror in a gimbal mount houses an electrostatic deformable membrane for the modal corrections. Piezoelectric actuators are attached behind the mirror for tilt correction. Wavefronts triggering the electrode detectors in the mirror also result in generation of a map of the wave-front errors. Compensating phase distributions for successive waves are calculated automatically by an expansion of the phase distortions into modes of a set of basis functions. Turbulence compensation is accomplished with Zernike polynomials if only a small number of modes is present, while Karhunen-Loeve functions serve for any number of modes. Phase aberrations are detected by diode arrays connected to amplifier tubes. Actual measurement of the wavefront phase is performed by a shearing interferometer and by use of an iterative algorithm to assay the intensity distribution of the image.

  6. Modeling for deformable mirrors and the adaptive optics optimization program

    SciTech Connect

    Henesian, M.A.; Haney, S.W.; Trenholme, J.B.; Thomas, M.

    1997-03-18

    We discuss aspects of adaptive optics optimization for large fusion laser systems such as the 192-arm National Ignition Facility (NIF) at LLNL. By way of example, we considered the discrete actuator deformable mirror and Hartmann sensor system used on the Beamlet laser. Beamlet is a single-aperture prototype of the 11-0-5 slab amplifier design for NIF, and so we expect similar optical distortion levels and deformable mirror correction requirements. We are now in the process of developing a numerically efficient object oriented C++ language implementation of our adaptive optics and wavefront sensor code, but this code is not yet operational. Results are based instead on the prototype algorithms, coded-up in an interpreted array processing computer language.

  7. Flextensional Single Crystal Piezoelectric Actuators for Membrane Deformable Mirrors

    NASA Technical Reports Server (NTRS)

    Jiang, Xiaoning; Sahul, Raffi; Hackenberger, Wesley S.

    2006-01-01

    Large aperture and light weight space telescopes requires adaptive optics with deformable mirrors capable of large amplitude aberration corrections at a broad temperature range for space applications including NASA missions such as SAFIR, TPF, Con-X, etc. The single crystal piezoelectric actuators produced at TRS offer large stroke, low hysteresis, and an excellent cryogenic strain response. Specifically, the recently developed low profile, low voltage flextensional single crystal piezoelectric actuators with dimensions of 18 x 5 x 1 mm showed stroke larger than 95 microns under 300 V. Furthermore, flextensional actuator retained approx. 40-50% of its room temperature strain at liquid Nitrogen environment. In this paper, ATILA FEM design of flextensional actuators, actuator fabrication, and characterization results will be presented for the future work on membrane deformable mirror.

  8. Performance analysis of two high actuator count MEMS deformable mirrors

    NASA Astrophysics Data System (ADS)

    Ryan, Peter J.; Cornelissen, Steven A.; Lam, Charlie V.; Bierden, Paul A.

    2013-03-01

    Two new MEMS deformable mirrors have been designed and fabricated, one having a continuous facesheet with an active aperture of 20mm and 2040 actuators and the other, a similarly sized segmented tip tilt piston DM containing 1021 elements and 3063 actuators. The surface figures, electro mechanical performances, and actuator yield of these devices, with statistical information, are reported here. The statistical distributions of these measurements directly illustrate the surface variance of Boston Micromachines deformable mirrors. Measurements of the surface figure were also performed with the elements at different actuation states. Also presented here are deviations of the surface figure under actuation versus at its rest state, the electromechanical distribution, and a dynamic analysis.

  9. Smart structures for deformable mirrors actuated by piezocomposites

    NASA Astrophysics Data System (ADS)

    Riva, M.; Di Sanzo, D.; Airoldi, A.; Sala, G.; Zerbi, F. M.

    2010-07-01

    Deformable mirrors actuated by smart structures are promising devices for next generation astronomical instrumentation. The piezo technology and in particular piezoceramics is currently among the most investigated structural materials. Fragility makes Ceramic materials extremely vulnerable to accidental breakage during bonding and embedding processes and limits the ability to comply to curved surfaces (typical of mirrors). Moreover lead-based piezoceramics typically have relevant additional masses. To overcome these limitations, we studied the applicability of composites piezoceramics actuators to smart structures with these purposes. We developed a combined Finite Element and Raytracing analysis devoted to a parametric performance predictions of a smart Piezocomposites based substrate applicable to deformable mirrors. We took in detail into account the possibility to change the focal length of the mirror keeping a satisfactory image quality. In this paper we present a specific type of Piezocomposite actuators and numerical/experimental techniques purposely developed to integrate them into smart structures. We evaluated numerical and experimental results comparing bonding and embedding of these devices.

  10. Miniature non-mechanical zoom camera using deformable MOEMS mirrors

    NASA Astrophysics Data System (ADS)

    Kaylor, Brant M.; Wilson, Christopher R.; Greenfield, Nathan J.; Roos, Peter A.; Seger, Eric M.; Moghimi, Mohammad J.; Dickensheets, David L.

    2012-03-01

    We present a miniature non-mechanical zoom camera using deformable MOEMS mirrors. Bridger Photonics, Inc. (Bridger) in collaboration with Montana State University (MSU), has developed electrostatically actuated deformable MEMS mirrors for use in compact focus control and zoom imaging systems. Applications including microscopy, endomicroscopy, robotic surgery and cell-phone cameras. In comparison to conventional systems, our MEMS-based designs require no mechanically moving parts. Both circular and elliptical membranes are now being manufactured at the wafer level and possess excellent optical surface quality (membrane flatness < λ/4). The mirror diameters range from 1 - 4 mm. For membranes with a 25 μm air gap, the membrane stroke is 10 μm. In terms of the optical design, the mirrors are considered variable power optical elements. A device with 2 mm diameter and 10 μm stroke can vary its optical power over 40 diopters or 0.04mm∧(-1). Equivalently, this corresponds to a focal length ranging from infinity to 25 mm. We have designed and demonstrated a zoom system using two MOEMS elements and exclusively commercial off-the-shelf optical components to achieve an optical zoom of 1.9x with a 15° full field of view. The total optical track length of the system is 36 mm. The design is approximately 30 mm x 30 mm x 20 mm including the optomechanical housing and image sensor. With custom optics, we anticipate achieving form factors that are compatible with incorporation into cell phones.

  11. Optical calibration and test of the VLT Deformable Secondary Mirror

    NASA Astrophysics Data System (ADS)

    Briguglio, Runa; Xompero, Marco; Riccardi, Armando; Andrighettoni, Mario; Pescoller, Dietrich; Biasi, Roberto; Gallieni, Daniele; Vernet, Elise; Kolb, Johann; Arsenault, Robin; Madec, Pierre-Yves

    2013-12-01

    The Deformable Secondary Mirror (DSM) for the VLT (ESO) represents the state-of-art of the large-format deformable mirror technology with its 1170 voice-coil actuators and its internal metrology based on actuator co-located capacitive sensors to control the shape of the 1.12m-diameter 2mm-thick convex shell. The present paper reports the results of the optical characterization of the mirror unit with the ASSIST facility located at ESO-Garching and executed in a collaborative effort by ESO, INAF-Osservatorio Astrofisico di Arcetri and the DSM manufacturing companies (Microgate s.r.l. and A.D.S. International s.r.l.). The main purposes of the tests are the optical characterization of the shell flattening residuals, the corresponding calibration of flattening commands, the optical calibration of the capacitive sensors and the optical calibration of the mirror influence functions. The results are used for the optical acceptance of the DSM and to allow the next test phase coupling the DSM with the wave-front sensor modules of the new Adaptive Optics Facility (AOF) of ESO.

  12. On-Chip High-Resolution Beam Scanner Based on Bragg Reflector Slow-Light Waveguide Amplifier and Tunable Micro-Electro-Mechanical System Vertical Cavity Surface Emitting Laser

    NASA Astrophysics Data System (ADS)

    Nakahama, Masanori; Gu, Xiaodong; Shimada, Toshikazu; Koyama, Fumio

    2012-04-01

    We propose a monolithic beam scanner consisting of a Bragg reflector slow-light waveguide amplifier and a tunable micro-electro-mechanical vertical cavity surface emitting laser. Continuous beam steering of over 30° and a narrow divergence angle of below 0.1° are predicted, which gives us a number of resolution points over 300. In addition, the modeling on saturation characteristics of a slow light amplifier shows a possibility of the maximum output power of over 10 mW.

  13. Smart structures for deformable mirrors actuated by shape memory alloy

    NASA Astrophysics Data System (ADS)

    Riva, M.; Bettini, P.; Di Landro, L.; Sala, G.; Zerbi, F. M.

    2010-07-01

    Deformable mirrors actuated by smart structures are promising devices for next generation astronomical instrumentation. Thermal activated Shape Memory Alloys are materials able to recover their original shape, after an external deformation, if heated above a characteristic temperature. If the recovery of the shape is completely or partially prevented by the presence of constraints, the material can generate recovery stress. Thanks to this feature, these materials can be positively exploited in Smart Structures if properly embedded into host materials. This paper will show the technological processes developed for an efficient use of SMA-based actuators embedded in smart structures tailored to astronomical instrumentation. In particular the analysis of the interface with the host material. Some possible modeling approaches to the actuators behavior will be addressed taking into account trade-offs between detailed analysis and overall performance prediction as a function of the computational time. We developed a combined Finite Element and Raytracing analysis devoted to a parametric performance predictions of a SMA based substrate applicable to deformable mirrors. We took in detail into account the possibility to change the focal length of the mirror keeping a satisfactory image quality. Finally a possible approach with some preliminary results for an efficient control system for the strongly non-linear SMA actuators will be presented.

  14. Deformable mirrors: design fundamentals for force actuation of continuous facesheets

    NASA Astrophysics Data System (ADS)

    Ravensbergen, S. K.; Hamelinck, R. F. H. M.; Rosielle, P. C. J. N.; Steinbuch, M.

    2009-08-01

    Adaptive Optics is established as essential technology in current and future ground based (extremely) large telescopes to compensate for atmospheric turbulence. Deformable mirrors for astronomic purposes have a high number of actuators (> 10k), a relatively large stroke (> 10μm) on a small spacing (< 10mm) and a high control bandwidth (> 100Hz). The availability of piezoelectric ceramics as an actuator principle has driven the development of many adaptive deformable mirrors towards inappropriately stiff displacement actuation. This, while the use of force actuation supersedes piezos in performance and longevity while being less costly per channel by a factor of 10-20. This paper presents a model which is independent of the actuator type used for actuation of continuous facesheet deformable mirrors, to study the design parameters such as: actuator spacing & coupling, influence function, peak-valley stroke, dynamical behavior: global & local, etc. The model is validated using finite element simulations and its parameters are used to derive design fundamentals for optimization.

  15. Polymer-based micro-deformable mirror for adaptive optics

    NASA Astrophysics Data System (ADS)

    Liotard, Arnaud; Zamkotsian, Frederic; Conedera, Veronique; Fabre, Norbert; Lanzoni, Patrick; Camon, Henri; Chazallet, Frederic

    2006-01-01

    Highly performing adaptive optical (AO) systems are mandatory for next generation giant telescopes as well as next generation instrumentation for 10m-class telescopes, for studying new fields like circumstellar disks and extra-solar planets. These systems require deformable mirrors with very challenging parameters, including number of actuators up to 250 000 and inter-actuator spacing around 500μm. MOEMS-based devices are promising for future deformable mirrors. We are currently developing a micro-deformable mirror (MDM) based on an array of electrostatic actuators with attachment posts to a continuous mirror on top. In order to reach large stroke for low driving voltage, the originality of our approach lies in the elaboration of a sacrificial layer and of a structural layer made of polymer materials. We have developed the first polymer piston-motion actuator: a 10μm thick mobile plate with four springs attached to the substrate, and with an air gap of 10μm exhibits a piston motion of 2μm for 30V, and measured resonance frequency of 6.5kHz is well suited for AO systems. The electrostatic force provides a non-linear actuation, while AO systems are based on linear matrices operations. We have successfully developed a dedicated 14-bit electronics in order to "linearize" the actuation. Actual location of the actuator versus expected location of the actuator is obtained with a standard deviation of 21 nm. Comparison with FEM models shows very good agreement, and design of a complete polymer-based MDM has been done.

  16. Control of a woofer tweeter system of deformable mirrors

    NASA Astrophysics Data System (ADS)

    Hampton, Peter J.; Conan, Rodolphe; Bradley, Colin; Agathoklis, Pan

    2006-06-01

    This paper describes the control of two deformable mirrors (DM) and a tip tilt mirror for adaptive optics. The purpose of this experimental adaptive optics system at the University of Victoria is to prove the Woofer Tweeter concept for use in instruments for the Thirty Meter Telescope (TMT) which is currently under development. The first deformable mirror is a large stroke DM (Woofer) capable of lower frequency correction in both the temporal and spatial domains. The other DM (Tweeter) is capable of the high temporal and spatial frequency corrections of the turbulence. The response speed of the Woofer is incorporated into the Tweeter controller in order to allow for appropriate offloading from the Tweeter to the Woofer. In order to determine which Tweeter shapes must compensate for the slower Woofer and which are not coupled to the Woofer, the cross correlation of the devices is determined. The method of converting the wave front sensor (WFS) measurements to control signal error is given. The transfer functions of the controller are provided, along with rejection ratio plots, bandwidths and amplitude response to system noise.

  17. MEMS deformable mirror embedded wavefront sensing and control system

    NASA Astrophysics Data System (ADS)

    Owens, Donald; Schoen, Michael; Bush, Keith

    2006-01-01

    Electrostatic Membrane Deformable Mirror (MDM) technology developed using silicon bulk micro-machining techniques offers the potential of providing low-cost, compact wavefront control systems for diverse optical system applications. Electrostatic mirror construction using bulk micro-machining allows for custom designs to satisfy wavefront control requirements for most optical systems. An electrostatic MDM consists of a thin membrane, generally with a thin metal or multi-layer high-reflectivity coating, suspended over an actuator pad array that is connected to a high-voltage driver. Voltages applied to the array elements deflect the membrane to provide an optical surface capable of correcting for measured optical aberrations in a given system. Electrostatic membrane DM designs are derived from well-known principles of membrane mechanics and electrostatics, the desired optical wavefront control requirements, and the current limitations of mirror fabrication and actuator drive electronics. MDM performance is strongly dependent on mirror diameter and air damping in meeting desired spatial and temporal frequency requirements. In this paper, we present wavefront control results from an embedded wavefront control system developed around a commercially available high-speed camera and an AgilOptics Unifi MDM driver using USB 2.0 communications and the Linux development environment. This new product, ClariFast TM, combines our previous Clarifi TM product offering into a faster more streamlined version dedicated strictly to Hartmann Wavefront sensing.

  18. Correction of an active space telescope mirror using a deformable mirror in a woofer-tweeter configuration

    NASA Astrophysics Data System (ADS)

    Allen, Matthew R.; Kim, Jae Jun; Agrawal, Brij N.

    2016-04-01

    The Naval Postgraduate School's segmented mirror telescope (SMT) was developed using prototype silicon carbide active hybrid mirror technology to demonstrate lower cost and rapid manufacture of primary mirror segments for a space telescope. The developmental mirror segments used too few actuators limiting the ability to adequately correct the surface figure error. To address the unintended shortfall of the developmental mirrors, a deformable mirror is added to the SMT and control techniques are developed. The control techniques are similar to woofer-tweeter adaptive optics, where the SMT segment represents the woofer and the deformable mirror represents the tweeter. The optical design of an SMT woofer-tweeter system is presented, and the impacts of field angle magnification on the placement and size of the deformable mirror are analyzed. A space telescope woofer-tweeter wavefront control technique is proposed using a global influence matrix and closed-loop constrained minimization controller. The control technique simultaneously manipulates the woofer and tweeter mirrors. Simulation and experimental results demonstrate a significant improvement in wavefront error of the primary mirror and the control technique shows significant wavefront error improvement compared to sequentially controlling the woofer and tweeter mirrors.

  19. Experimental investigation of the deformable mirror with bidirectional thermal actuators.

    PubMed

    Huang, Lei; Ma, Xingkun; Gong, Mali; Bian, Qi

    2015-06-29

    A deformable mirror with actuators of thermoelectric coolers (TECs) is introduced in this paper. Due to the bidirectional thermal actuation property of the TEC, both upward and downward surface control is available for the DM. The response functions of the actuators are investigated. A close-loop wavefront control experiment is performed too, where the defocus and the astigmatism were corrected. The results reveal that there is a promising prospect for the novel design to be used in corrections of static aberrations, such as in the Inertial Confinement Fusion (ICF). PMID:26191759

  20. Shaping light: MOEMS deformable mirrors for microscopes and telescopes

    NASA Astrophysics Data System (ADS)

    Bifano, Thomas

    2010-02-01

    Micromachined deformable mirrors (DMs) have enabled rapid advances in applications ranging from large telescope astronomy and free space laser communication to biological microscopy and retinal imaging over the past decade. In this talk I describe our efforts at Boston University and at Boston Micromachines Corporation to design, fabricate, and control MOEMS DMs for adaptive optics (AO) applications. Integration of the DMs in AO systems is described, along with results demonstrating unprecedented advances in resolution and contrast in microscopes and telescopes challenged by unavoidable wavefront aberrations. MEMS-DM research offers the rare opportunity to introduce technology that is both more economical and more capable than the state-of-the-art.

  1. Optimal mirror deformation for multi conjugate adaptive optics systems

    NASA Astrophysics Data System (ADS)

    Raffetseder, S.; Ramlau, R.; Yudytskiy, M.

    2016-02-01

    Multi conjugate adaptive optics (MCAO) is a system planned for all future extremely large telescopes to compensate in real-time for the optical distortions caused by atmospheric turbulence over a wide field of view. The principles of MCAO are based on two inverse problems: a stable tomographic reconstruction of the turbulence profile followed by the optimal alignment of multiple deformable mirrors (DMs), conjugated to different altitudes in the atmosphere. We present a novel method to treat the optimal mirror deformation problem for MCAO. Contrary to the standard approach where the problem is formulated over a discrete set of optimization directions we focus on the solution of the continuous optimization problem. In the paper we study the existence and uniqueness of the solution and present a Tikhonov based regularization method. This approach gives us the flexibility to apply quadrature rules for a more sophisticated discretization scheme. Using numerical simulations in the context of the European extremely large telescope we show that our method leads to a significant improvement in the reconstruction quality over the standard approach and allows to reduce the numerical burden on the computer performing the computations.

  2. Computation of Static Shapes and Voltages for Micromachined Deformable Mirrors with Nonlinear Electrostatic Actuators

    NASA Technical Reports Server (NTRS)

    Wang, P. K. C.; Hadaegh, F. Y.

    1996-01-01

    In modeling micromachined deformable mirrors with electrostatic actuators whose gap spacings are of the same order of magnitude as those of the surface deformations, it is necessary to use nonlinear models for the actuators. In this paper, we consider micromachined deformable mirrors modeled by a membrane or plate equation with nonlinear electrostatic actuator characteristics. Numerical methods for computing the mirror deformation due to given actuator voltages and the actuator voltages required for producing the desired deformations at the actuator locations are presented. The application of the proposed methods to circular deformable mirrors whose surfaces are modeled by elastic membranes is discussed in detail. Numerical results are obtained for a typical circular micromachined mirror with electrostatic actuators.

  3. Optical joint correlation using the deformable mirror device

    NASA Technical Reports Server (NTRS)

    Knopp, Jerome

    1989-01-01

    An experimental investigation of the Deformable Mirror Device (DMD) developed by Texas Instruments at Dallas for use in object identification was completed. The DMD was tested as a joint correlator. The DMD was used as a spatial light modulator on which the squared modulus of the Fourier transform of test object pairs was written. The squared modulus was phase encoded on the DMD after it had been thresholded and rewritten as a binary phase function. The thresholding was found to produce a sharp peak in the autocorrelation when the test objects were matched and no significant peak in the case of distinct objects. It was concluded that the use of the DMD as a joint correlator looks promising and further studies should be carried out.

  4. Deformable mirrors for x-ray astronomy and beyond

    NASA Astrophysics Data System (ADS)

    Ulmer, M. P.; Graham, M. E.; Vaynman, S.; Cao, J.; Takacs, P. Z.

    2011-05-01

    We discuss a technique of shape modification that can be applied to thin walled (~; 100-400 micron thickness) electroformed replicated optics or slumped glass optics to improve the near net shape of the mirror as well as the mid-frequency ripple. The process involves sputter deposition of a magnetic smart material (MSM) film onto a permanently magnetic material. The MSM material exhibits strains about 400 times stronger than ordinary ferromagnetic materials. The deformation process involves a magnetic write head which traverses the surface, and under the guidance of active metrology feedback,locally magnetizes the surface to impart strain where needed. Designs and basic concepts as applied to space borne X-ray optics will be described.

  5. Actuating the deformable mirror: a multiphysics design approach

    NASA Astrophysics Data System (ADS)

    Del Vecchio, Ciro; Biasi, Roberto; Gallieni, Daniele; Riccardi, Armando; Spairani, Roberto

    2008-07-01

    The crucial component of an Adaptive Optics unit is the actuation system of the deformable mirror. One possible implementation comprehends a linear force motor and a capacitive sensor providing the feedback measure signal. Due to the extreme accuracy required by the optics, a proper design of the actuator is essential in order to fulfill the specifications. In the device, mechanics, electrostatics, electromagnetism and thermal effects are mutually related, and they have to be properly considered in the design phase. This paper analyzes such a multiphysics behavior of the actuation system, providing an inter-disciplinary approach able to define the optimized device: a capacitive sensor measuring the displacements at the nanometer accuracy and a closed loop linear motor delivering the requested force with the lowest possible power dissipation, in order to minimize the degrading of the optical waves propagation.

  6. Silicon carbide deformable mirror with 37 actuators for adaptive optics

    NASA Astrophysics Data System (ADS)

    Ahn, Kyohoon; Rhee, Hyug-Gyo; Yang, Ho-Soon; Kihm, Hagyong

    2015-11-01

    We present a prototype of a silicon carbide (SiC) deformable mirror (DM) for high power laser applications. The DM has a continuous SiC faceplate, the diameter and the thickness of which are 100 mm and 2 mm, respectively, and 37 stack-type piezoelectric actuators arranged in a rectangular grid. Compared with the glass faceplates used for conventional DMs, SiC has a high thermal diffusivity that effectively minimizes mirror distortions due to thermal gradients. The faceplate is thick enough for possible integration with monolithic cooling channels inside the faceplate. The faceplate without cooling channels presented in this paper has a high bending stiffness compared with glass DMs, but the proposed actuator configuration has flexure supports to reduce the shear stress at the adhesive while preserving optical performances. To examine the characteristics of the SiC DM, we simulated influence functions (IFs) by using a finite element analysis and then compared these results with the IF measured by using an optical interferometer. The optical performance of the DM was verified by generating Zernike polynomial modes based on the measured IF.

  7. Control of a deformable mirror subject to structural disturbance

    NASA Astrophysics Data System (ADS)

    Allen, Matthew R.; Kim, Jae Jun; Agrawal, Brij

    2008-04-01

    Future space based deployable telescopes will be subject to non-atmospheric disturbances. Jitter and optical misalignment on a spacecraft can be caused by mechanical noise of the spacecraft, and settling after maneuvers. The introduction of optical misalignment and jitter can reduce the performance of an optical system resulting in pointing error and contributing to higher order aberrations. Adaptive optics can be used to control jitter and higher order aberrations in an optical system. In this paper, wavefront control methods for the Naval Postgraduate School adaptive optics testbed are developed. The focus is on removing structural noise from the flexible optical surface using discrete time proportional integral control with second order filters. Experiments using the adaptive optics testbed successfully demonstrate wavefront control methods, including a combined iterative feedback and gradient control technique. This control technique results in a three time improvement in RMS wavefront error over the individual controllers correcting from a biased mirror position. Second order discrete time notch filters are also used to remove induced low frequency actuator and sensor noise at 2Hz. Additionally a 2 Hz structural disturbance is simulated on a Micromachined Membrane Deformable Mirror and removed using discrete time notch filters combined with an iterative closed loop feedback controller, showing a 36 time improvement in RMS wavefront error over the iterative closed loop feedback alone.

  8. Piezoelectric deformable mirror technologies for astronomy at IOE, CAS

    NASA Astrophysics Data System (ADS)

    Guan, Chunlin; Fan, Xinlong; Zhang, Xiaojun; Zhou, Hong; Mu, Jinbo; Xue, Lixia; Wei, Kai; Xian, Hao; Rao, Changhui; Zhang, Yudong; Ling, Ning

    2014-07-01

    Institute of Optics & Electronics (IOE), Chinese Academy of Sciences (CAS) has more than 30 years' experience on piezoelectric deformable mirror (DM) technologies research and developing since early 1980s. Several DMs of IOE have been used in many different application systems. A brief history of piezoelectric DMs development in IOE and several recently achievements, and the main characters, performance and test results of the DMs for astronomy will be presented in this paper. 1) High-order DM. DM prototype with 913-element for 4m telescope has been fabricated and tested in laboratory. 2) Adaptive Secondary Mirror (ASM). A 73-element ASM prototype with 12 microns stroke for 1.8m telescope has been fabricated. It will be installed onto the 1.8m telescope with a compact adaptive optics (AO) system. 3) Small spacing DM. A 6mm spacing 127-element DM based on the same construction with the High-order DM has been used in AO system of 1m New Vacuum Solar Telescope (NVST) in Yunnan Observatories. Higher density (3mm spacing) DM based on a novel construction has being developed. In 2012, the novel DM prototype with 100-element was fabricated and tested carefully in laboratory. Beside, a 6mm spacing 151-element DM based on the novel construction has being fabricated for the solar AO system.

  9. Path Length Control in a Nulling Coronagraph with a MEMS Deformable Mirror and a Calibration Interferometer

    NASA Technical Reports Server (NTRS)

    Rao, Shanti R.; Wallacea, J. Kent; Samuele, Rocco; Chakrabarti, Supriya; Cook, Timothy; Hicks, Brian; Jung, Paul; Lane, Benjamin; Levine, B. Martin; Mendillo, Chris; Schmidtlin, Edouard; Shao, Mike; Stewart, Jason B.

    2008-01-01

    We report progress on a nulling coronagraph intended for direct imaging of extrasolar planets. White light is suppressed in an interferometer, and phase errors are measured by a second interferometer. A 1020-pixel MEMS deformable mirror in the first interferometer adjusts the path length across the pupil. A feedback control system reduces deflections of the deformable mirror to order of 1 nm rms.

  10. High-Resolution Adaptive Optics Scanning Laser Ophthalmoscope with Dual Deformable Mirrors

    SciTech Connect

    Chen, D C; Jones, S M; Silva, D A; Olivier, S S

    2006-08-11

    Adaptive optics scanning laser ophthalmoscope (AO SLO) has demonstrated superior optical quality of non-invasive view of the living retina, but with limited capability of aberration compensation. In this paper, we demonstrate that the use of dual deformable mirrors can effectively compensate large aberrations in the human retina. We used a bimorph mirror to correct large-stroke, low-order aberrations and a MEMS mirror to correct low-stroke, high-order aberration. The measured ocular RMS wavefront error of a test subject was 240 nm without AO compensation. We were able to reduce the RMS wavefront error to 90 nm in clinical settings using one deformable mirror for the phase compensation and further reduced the wavefront error to 48 nm using two deformable mirrors. Compared with that of a single-deformable-mirror SLO system, dual AO SLO offers much improved dynamic range and better correction of the wavefront aberrations. The use of large-stroke deformable mirrors provided the system with the capability of axial sectioning different layers of the retina. We have achieved diffraction-limited in-vivo retinal images of targeted retinal layers such as photoreceptor layer, blood vessel layer and nerve fiber layers with the combined phase compensation of the two deformable mirrors in the AO SLO.

  11. High-resolution adaptive optics scanning laser ophthalmoscope with multiple deformable mirrors

    DOEpatents

    Chen, Diana C.; Olivier, Scot S.; Jones; Steven M.

    2010-02-23

    An adaptive optics scanning laser ophthalmoscopes is introduced to produce non-invasive views of the human retina. The use of dual deformable mirrors improved the dynamic range for correction of the wavefront aberrations compared with the use of the MEMS mirror alone, and improved the quality of the wavefront correction compared with the use of the bimorph mirror alone. The large-stroke bimorph deformable mirror improved the capability for axial sectioning with the confocal imaging system by providing an easier way to move the focus axially through different layers of the retina.

  12. Wavefront correction with a ferrofluid deformable mirror: experimental results and recent developments

    NASA Astrophysics Data System (ADS)

    Brousseau, Denis; Borra, Ermanno F.; Thibault, Simon; Ritcey, Anna M.; Parent, Jocelyn; Seddiki, Omar; Déry, Jean-Philippe; Faucher, Luc; Vassallo, Julien; Naderian, Azadeh

    2008-07-01

    We present the research status of a deformable mirror made of a magnetic liquid whose surface is actuated by a triangular array of small current carrying coils. We demonstrate that the mirror can correct a 11 μm low order aberrated wavefront to a residual RMS wavefront error 0.05 μm. Recent developments show that these deformable mirrors can reach a frequency response of several hundred hertz. A new method for linearizing the response of these mirrors is also presented.

  13. An RF Therapy System for Breast Cancer Using Dual Deformable Mirrors — Computational Study

    NASA Astrophysics Data System (ADS)

    Arunachalam, Kavitha; Udpa, Satish S.; Udpa, Lalita

    2007-03-01

    Breast cancer is the second leading cause of cancer deaths amongst women in the United States. In the past two decades, the potential of non-ionizing high power RF waves to destroy cancerous biological tissues is actively investigated for cancer therapy. This paper presents the computational feasibility study of an alternative mode of electromagnetic radiation therapy that employs dual source and deformable mirror. The adaptive focusing capability of the deformable mirror is exploited for preferential energy deposition at the tumor site in the breast irradiated by electromagnetic radiation. The outcome of the computational study for the proposed deformable mirror-based thermal therapy for breast cancer is presented in this paper.

  14. Prototype Small Footprint Amplifier for Piezoelectric Deformable Mirrors

    NASA Astrophysics Data System (ADS)

    Caputa, Kris; Herriot, Glen; Niebergal, Joel; Zielinski, Adam

    2011-09-01

    AO subsystems of the ELT observatories will incorporate deformable mirrors with an order of magnitude larger number of piezoelectric actuators than the AO systems currently deployed. Simply scaling up the drive electronics that are presently available commercially would substantially drive up the AO cost, pose unacceptably high demands for the supply power and heat dissipation, and occupy large physical volume. We have set out to prototype a high voltage amplifier that is compact enough to allow packaging 100 amplifier channels on a single 6U Eurocard with the goal to have a DM drive channel density of 1200 per 6U VME crate. Individual amplifier circuits should be driven by a multichannel A/D converter, consume no more than 0.5W from the +/-400V power supply, be slew rate limited in hardware, and be short-circuit protected. The component cost should be an order of magnitude less than the integrated circuit high voltage amplifiers currently on the market. We started out with modeling candidate circuits in SPICE, then built physical prototypes using inexpensive off the shelf components. In this paper we present experimental results of exposing several prototype circuits to both normal operating conditions and foreseeable fault conditions. The performance is evaluated against the AO requirements for the output range and bandwidth and the DM actuator safety requirements.

  15. VLT deformable secondary mirror: integration and electromechanical tests results

    NASA Astrophysics Data System (ADS)

    Biasi, R.; Andrighettoni, M.; Angerer, G.; Mair, C.; Pescoller, D.; Lazzarini, P.; Anaclerio, E.; Mantegazza, M.; Gallieni, D.; Vernet, E.; Arsenault, R.; Madec, P.-Y.; Duhoux, P.; Riccardi, A.; Xompero, M.; Briguglio, R.; Manetti, M.; Morandini, M.

    2012-07-01

    The VLT Deformable secondary is planned to be installed on the VLT UT#4 as part of the telescope conversion into the Adaptive Optics test Facility (AOF). The adaptive unit is based on the well proven contactless, voice coil motor technology that has been already successfully implemented in the MMT, LBT and Magellan adaptive secondaries, and is considered a promising technical choice for the forthcoming ELT-generation adaptive correctors, like the E-ELT M4 and the GMT ASM. The VLT adaptive unit has been recently assembled after the completion of the manufacturing and modular test phases. In this paper, we present the most relevant aspects of the system integration and report the preliminary results of the electromechanical tests performed on the unit. This test campaign is a typical major step foreseen in all similar systems built so far: thanks to the metrology embedded in the system, that allows generating time-dependent stimuli and recording in real time the position of the controlled mirror on all actuators, typical dynamic response quality parameters like modal settling time, overshoot and following error can be acquired without employing optical measurements. In this way the system dynamic and some aspect of its thermal and long term stability can be fully characterized before starting the optical tests and calibrations.

  16. Imaging performance of elliptical-boundary varifocal mirrors in active optical systems

    NASA Astrophysics Data System (ADS)

    Lukes, Sarah Jane

    Micro-electro-mechanical systems deformable-membrane mirrors provide a means of focus control and attendant spherical aberration correction for miniaturized imaging systems. The technology has greatly advanced in the last decade, thereby extending their focal range capabilities. This dissertation describes a novel SU-8 2002 silicon-on-insulator wafer deformable mirror. A 4.000 mm x 5.657 mm mirror for 45o incident light rays achieves 22 mum stroke or 65 diopters, limited by snapdown. The mirrors show excellent optical quality while flat. Most have peak-to-valley difference of less than 150 nm and root-mean-square less than 25 nm. The process proves simple, only requiring a silicon-on-insulator wafer, SU-8 2002, and a metal layer. Xenon difluoride etches the silicon to release the mirrors. Greater than 90% of the devices survive fabrication and release. While current literature includes several aberration analyses on static mirrors, analyses that incorporate the dynamic nature of these mirrors do not exist. Optical designers may have a choice between deformable mirrors and other types of varifocal mirrors or lenses. Furthermore, a dynamic mirror at an incidence angle other than normal may be desired due to space limitations or for higher throughput (normal incidence requires a beam splitter). This dissertation presents an analysis based on the characteristic function of the system. It provides 2nd and 3rd order aberration coefficients in terms of dynamic focus range and base ray incidence angle. These afford an understanding of the significance of different types of aberrations. Root-mean-square and Strehl calculations provide insight into overall imaging performance for various conditions. I present general guidelines for maximum incidence angle and field of fiew that provide near diffraction-limited performance. Experimental verification of the MEMS mirrors at 5o and 45o incidence angles validates the analytical results. A Blu-ray optical pick-up imaging

  17. Active control of a large deformable mirror for future E-ELT

    NASA Astrophysics Data System (ADS)

    Gasmi, R.; Le Bihan, D.; Dournaux, J. L.; Sinquin, J. C.; Jagourel, P.

    2010-07-01

    Increasing dimensions of ground based telescopes and adaptive optics needs for these instruments require wide deformable mirrors with a high number of actuators to compensate the effects of the atmospheric turbulence on the wave fronts. The new dimensions and characteristics of these deformable mirrors lead to the apparition of structural vibrations, which may reduce the rejection band width of the adaptive optics control loop. The aim of this paper is the study of the dynamic behavior of a 1-meter prototype of E-ELT's deformable mirror in order to identify its eigenmodes and to propose some ways to control its vibrations. We first present the first eigenmodes of the structure determined by both finite element analysis and experimental modal analysis. Then we present the frequency response of the prototype to a tilt excitation to estimate the effects of its vibrations on the adaptive optics loop. Finally we suggest a method to control the dynamics of the deformable mirror.

  18. A monolithic deformable mirror with latchable mechanical actuation (LATCHAMAN) for space-borne telescopes

    NASA Astrophysics Data System (ADS)

    Enya, Keigo; Kataza, Hirokazu; Fukushima, Mitsuhiro; Mitsui, Kenji; Okada, Norio; Iwashita, Hikaru; Haze, Kanae; Takahashi, Aoi; Kotani, Takayuki; Yamamuro, Tomoyasu; Kobayashi, Hitomi

    2014-09-01

    We present the concept, design, fabrication, and evaluation of a new deformable mirror (DM), which is latchable, compact, and designed to be applicable for cryogenic environments. The main body of a prototype DM was fabricated from a monolithic cuboid of aluminum using wire electrical discharge machining (EDM). A flexible structure was constructed inside the block by 3-dimensionally crossed hollowing using the EDM. The prototype has 6 × 6 channels, and its volume is 27 mm × 27 mm × 30 mm. The mirror was formed on the surface of the aluminum block using a highprecision NC lathe. The surface figure of the mirror was evaluated and 34 nm rms was obtained. The evaluated surface roughness for the center and off-center areas of the mirror was 9.2 nm rms and 7.6 nm rms, respectively Screws set at the back of the block deform the mirror via springs and the internal flexible structure. We present our first demonstration of deformation of the mirror carried out at ambient temperature. The relationship between the displacement of the screws and the deformation of the mirror was evaluated. Consequently, a linear relationship was confirmed, and no significant hysteresis was found. The application of such mirrors to telescopes used for various different objectives is discussed. We conclude that a DM based on our concept can be used for wavefront correction of space-borne telescopes, especially in the infrared wavelength region.

  19. High-resolution adaptive optics scanning laser ophthalmoscope with dual deformable mirrors for large aberration correction

    SciTech Connect

    Chen, D; Jones, S M; Silva, D A; Olivier, S S

    2007-01-25

    Scanning laser ophthalmoscopes with adaptive optics (AOSLO) have been shown previously to provide a noninvasive, cellular-scale view of the living human retina. However, the clinical utility of these systems has been limited by the available deformable mirror technology. In this paper, we demonstrate that the use of dual deformable mirrors can effectively compensate large aberrations in the human retina, making the AOSLO system a viable, non-invasive, high-resolution imaging tool for clinical diagnostics. We used a bimorph deformable mirror to correct low-order aberrations with relatively large amplitudes. The bimorph mirror is manufactured by Aoptix, Inc. with 37 elements and 18 {micro}m stroke in a 10 mm aperture. We used a MEMS deformable mirror to correct high-order aberrations with lower amplitudes. The MEMS mirror is manufactured by Boston Micromachine, Inc with 144 elements and 1.5 {micro}m stroke in a 3 mm aperture. We have achieved near diffraction-limited retina images using the dual deformable mirrors to correct large aberrations up to {+-} 3D of defocus and {+-} 3D of cylindrical aberrations with test subjects. This increases the range of spectacle corrections by the AO systems by a factor of 10, which is crucial for use in the clinical environment. This ability for large phase compensation can eliminate accurate refractive error fitting for the patients, which greatly improves the system ease of use and efficiency in the clinical environment.

  20. A Piezoelectric Unimorph Deformable Mirror Concept by Wafer Transfer for Ultra Large Space Telescopes

    NASA Technical Reports Server (NTRS)

    Yang, Eui-Hyeok; Shcheglov, Kirill

    2002-01-01

    Future concepts of ultra large space telescopes include segmented silicon mirrors and inflatable polymer mirrors. Primary mirrors for these systems cannot meet optical surface figure requirements and are likely to generate over several microns of wavefront errors. In order to correct for these large wavefront errors, high stroke optical quality deformable mirrors are required. JPL has recently developed a new technology for transferring an entire wafer-level mirror membrane from one substrate to another. A thin membrane, 100 mm in diameter, has been successfully transferred without using adhesives or polymers. The measured peak-to-valley surface error of a transferred and patterned membrane (1 mm x 1 mm x 0.016 mm) is only 9 nm. The mirror element actuation principle is based on a piezoelectric unimorph. A voltage applied to the piezoelectric layer induces stress in the longitudinal direction causing the film to deform and pull on the mirror connected to it. The advantage of this approach is that the small longitudinal strains obtainable from a piezoelectric material at modest voltages are thus translated into large vertical displacements. Modeling is performed for a unimorph membrane consisting of clamped rectangular membrane with a PZT layer with variable dimensions. The membrane transfer technology is combined with the piezoelectric bimorph actuator concept to constitute a compact deformable mirror device with a large stroke actuation of a continuous mirror membrane, resulting in a compact A0 systems for use in ultra large space telescopes.

  1. Out-of-plane actuation with a sub-micron initial gap for reconfigurable terahertz micro-electro-mechanical systems metamaterials.

    PubMed

    Isozaki, Akihiro; Kan, Tetsuo; Takahashi, Hidetoshi; Matsumoto, Kiyoshi; Shimoyama, Isao

    2015-10-01

    We propose a reconfigurable terahertz (THz) metamaterial that can control the transmittance by out-of-plane actuation with changing the sub-micron gap distance between electrically coupled metamaterial elements. By using the out-of-plane actuation, it was possible to avoid contact between the coupled metamaterial elements across the small initial gap during the adjustment of the gap size. THz spectroscopy was performed during actuation, and the transmission dip frequency was confirmed to be tunable from 0.82 to 0.92 THz for one linear polarization state and from 0.80 to 0.91 THz for the other linear polarization; the two polarizations were orthogonal. The proposed approach will contribute to the development of tunable metamaterials based on structural deformations. PMID:26480137

  2. Analysis of the static deformation matching between numerical and experimental data on the voice-coil actuated deformable mirrors

    NASA Astrophysics Data System (ADS)

    Del Vecchio, Ciro; Briguglio, Runa; Riccardi, Armando; Xompero, Marco

    2014-08-01

    As any other modelling of a physical behavior, the numerical simulation of the mechanical response of an adaptive secondary mirror requires that the results match the experimental data. Such an agreement was recently demonstrated for the local mirror stiffness of the LBT and VLT Deformable Mirrors. A reliable modeling is a good tool for the extrapolation of the missing optical data (spider shadowing, edge vignetting, etc.) and a final goal method for simplifying, or even substituting, the complex optical measuring equipment required by the convex shells. In the present paper we compare the whole mirror deformation maps when a single actuator is poked, both in the optical data and in the numerical model. The limiting factors as well as a roadmap for future improvements will be identified.

  3. Temperature deformations of the mirror of a radio telescope antenna

    NASA Technical Reports Server (NTRS)

    Avdeyev, V. I.; Grach, S. A.; Kozhakhmetov, K. K.; Kostenko, F. I.

    1979-01-01

    The stress informed state of the mirror of an antenna, with a diameter of 3 m, for a radio interferometer used in space, and located in a temperature field is examined. The mirror represents a parabolic shell, consisting of 19 identical parts. The problem is based on representations of the thermoelasticity of thin shells.

  4. Space active optics: performance of a deformable mirror for in-situ wave-front correction in space telescopes

    NASA Astrophysics Data System (ADS)

    Laslandes, Marie; Hourtoule, Claire; Hugot, Emmanuel; Ferrari, Marc; Lopez, Céline; Devilliers, Christophe; Liotard, Arnaud; Chazallet, Frederic

    2012-09-01

    MADRAS (Mirror Active, Deformable and Regulated for Applications in Space) project aims at demonstrating the interest of Active Optics for space applications. We present the prototype of a 24 actuators, 100 mm diameter deformable mirror to be included in a space telescope's pupil relay to compensate for large lightweight primary mirror deformation. The mirror design has been optimized with Finite Element Analysis and its experimental performance characterized in representative conditions. The developed deformable mirror provides an efficient wave-front correction with a limited number of actuators and a design fitting space requirements.

  5. Largest in the world bimorph deformable mirror for high-power laser beam correction

    NASA Astrophysics Data System (ADS)

    Kudryashov, Alexis; Samarkin, Vadim; Aleksandrov, Alex; Borsoni, Giles; Jitsuno, Takahisa; Romanov, Pavel; Sheldakova, Julia

    2016-03-01

    The deformable mirror with the size of 410x468 mm controlled by the bimorph piezoceramic plates and multilayer piezoceramic stacks was developed. The results of the measurements of the response functions of all the actuators and of the surface shape of the deformable mirror are presented in this paper. The study of the mirror with a Fizeau interferometer and a Shack-Hartmann wavefront sensor has shown that it was possible to improve the flatness of the surface down to a residual roughness of 0.033 μm (RMS). The possibility of correction of the aberrations in high power lasers was numerically demonstrated.

  6. Hard X-ray nanofocusing using adaptive focusing optics based on piezoelectric deformable mirrors

    SciTech Connect

    Goto, Takumi; Nakamori, Hiroki; Sano, Yasuhisa; Matsuyama, Satoshi; Kimura, Takashi; Kohmura, Yoshiki; Tamasaku, Kenji; Yabashi, Makina; Ishikawa, Tetsuya

    2015-04-15

    An adaptive Kirkpatrick–Baez mirror focusing optics based on piezoelectric deformable mirrors was constructed at SPring-8 and its focusing performance characteristics were demonstrated. By adjusting the voltages applied to the deformable mirrors, the shape errors (compared to a target elliptical shape) were finely corrected on the basis of the mirror shape determined using the pencil-beam method, which is a type of at-wavelength figure metrology in the X-ray region. The mirror shapes were controlled with a peak-to-valley height accuracy of 2.5 nm. A focused beam with an intensity profile having a full width at half maximum of 110 × 65 nm (V × H) was achieved at an X-ray energy of 10 keV.

  7. Hard X-ray nanofocusing using adaptive focusing optics based on piezoelectric deformable mirrors

    NASA Astrophysics Data System (ADS)

    Goto, Takumi; Nakamori, Hiroki; Kimura, Takashi; Sano, Yasuhisa; Kohmura, Yoshiki; Tamasaku, Kenji; Yabashi, Makina; Ishikawa, Tetsuya; Yamauchi, Kazuto; Matsuyama, Satoshi

    2015-04-01

    An adaptive Kirkpatrick-Baez mirror focusing optics based on piezoelectric deformable mirrors was constructed at SPring-8 and its focusing performance characteristics were demonstrated. By adjusting the voltages applied to the deformable mirrors, the shape errors (compared to a target elliptical shape) were finely corrected on the basis of the mirror shape determined using the pencil-beam method, which is a type of at-wavelength figure metrology in the X-ray region. The mirror shapes were controlled with a peak-to-valley height accuracy of 2.5 nm. A focused beam with an intensity profile having a full width at half maximum of 110 × 65 nm (V × H) was achieved at an X-ray energy of 10 keV.

  8. Micro drilling using deformable mirror for beam shaping of ultra-short laser pulses

    NASA Astrophysics Data System (ADS)

    Smarra, Marco; Strube, Anja; Dickmann, Klaus

    2016-03-01

    Using ultra-short laser pulses for micro structuring or drilling applications reduces the thermal influence to the surrounding material. The best achievable beam profile equals a Gaussian beam. Drilling with this beam profile results in cylindrical holes. To vary the shape of the holes, the beam can either be scanned or - for single pulse and percussion drilling - manipulated by masks or lenses. A high flexible method for beam shaping can be realized by using a deformable mirror. This mirror contains a piezo-electric ceramic, which can be deformed by an electric potential. By separating the ceramic into independent controllable segments, the shape of the surface can be varied individually. Due to the closed surface of the mirror, there is no loss of intensity due to diffraction. The mirror deformation is controlled by Zernike polynomials and results e.g. in a lens behavior. In this study a deformable mirror was used to generate e.g. slits in thin steel foils by percussion drilling using ultra-short laser pulses. The influence of the cylindrical deformation to the laser beam and the resulting geometry of the generated holes was studied. It was demonstrated that due to the high update rate up to 150 Hz the mirror surface can be varied in each scan cycle, which results in a high flexible drilling process.

  9. Demonstration Of A Robust Composite Deformable Secondary Mirror With Low Surface Error

    NASA Astrophysics Data System (ADS)

    Ammons, Stephen; Coughenour, B.; Hart, M.; Romeo, R.; Martin, R.

    2011-01-01

    I discuss recent improvements in the development of carbon fiber reinforced polymer (CFRP) as a lightweight substrate for primary and deformable secondary mirrors on ground- and space-based telescopes. Weight reductions for ground-based primary mirrors can significantly affect cost: The weight and material cost of a large ground-based telescope go roughly as the primary mirror mass. CFRP composites provide several advantages as a substrate for thin-shell adaptive secondary mirrors as well, including high stiffness-to-weight ratio, low coefficient of thermal expansion (CTE), and robustness. We use an 8 cm prototype CFRP thin-shell deformable mirror to show that spatial CTE variation may be addressed with mounted actuators. I present measurements of surface quality at a range of temperatures characteristic of mountaintop observatories. The figure error of the Al-coated reflective surface under best actuator correction is 43 nm RMS, placing it into consideration for use in near-IR astronomy. The low surface error internal to the outer ring of actuators (17 nm RMS at 15 C and 33 nm RMS at -5 C) suggests that larger mirrors will have a similar figure quality under actuator correction on ground-based Adaptive Optics systems. Surface roughness is low (< 3 nm P-V) at a variety of temperatures. These experiments demonstrate CFRP's potential as a lightweight, robust substrate for thin-shell deformable secondary mirrors.

  10. Active optics experiments. II - Measurement of mirror deformation by holographic method

    NASA Astrophysics Data System (ADS)

    Itoh, Noboru; Mikami, Izumi; Miyawaki, Keizou; Sasaki, Aki; Tabata, Masao

    An active optics experiment was performed to study the feasibility of using an active correction system for the Japanese National Large Telescope (Wilson, 1986). A thin mirror was deformed with an active support mechanism and the mirror surface was measured by a holographic method. The experiment is performed for several cases of excess force distributions assigned at the supporting points. The results show good agreement with predictions from FEM analysis.

  11. Analysis of a compliant static deformable mirror for wavefront error cancellation

    NASA Astrophysics Data System (ADS)

    Penado, F. Ernesto; Clark, James H., III; Dugdale, Joel

    2011-10-01

    The Navy Prototype Optical Interferometer (NPOI) array, located near Flagstaff, Arizona, transports 12.5 cm diameter stellar radiation simultaneously from six primary collectors through a 9,000 cubic foot vacuum relay system prior to entering a specialized laboratory where further manipulations of each beam occur. The relay system redirects each 12.5 cm beam 10 times. Ground-based optical interferometry requires very high quality, ideally flat, relay mirrors. The mirrors used in the relay system have flatness deviation tolerance 32 nm peak-to-valley over the 18.3 cm clear aperture. Once mounted in the 10-element optical train, errors from each mirror tend to stack up and increase the resultant wavefront distortion for that path. This leads to reduced fringe contrast, fringe tracking, and number of observables. In a previous paper, it was shown that it is possible to mitigate the resultant wavefront distortion by using a phase-shifting interferometer combined with a single compliant static deformable mirror and control system. In that work, the mirrors tested showed a fairly uniform, concentric concavity deformation, which a single, centrally located actuator may significantly improve. In this paper, we extend the previous analysis to consider an off-center actuator acting on a mirror to counteract an asymmetric wavefront distortion resulting from the superposition of several relay mirrors. The shape applied to a single corrector mirror was determined from the resultant wavefront distortion of a 7-reflection optical relay system using phase-shifting interferometer data. Finite element analysis results indicating how resultant wavefront error from a collection of slightly deformed mirrors can be cancelled are presented and discussed.

  12. Deformation of partially pumped active mirrors for high average-power diode-pumped solid-state lasers.

    PubMed

    Albach, Daniel; LeTouzé, Geoffroy; Chanteloup, Jean-Christophe

    2011-04-25

    We discuss the deformation of a partially pumped active mirror amplifier as a free standing disk, as implemented in several laser systems. We rely on the Lucia laser project to experimentally evaluate the analytical and numerical deformation models. PMID:21643092

  13. Payload characterization for CubeSat demonstration of MEMS deformable mirrors

    NASA Astrophysics Data System (ADS)

    Marinan, Anne; Cahoy, Kerri; Webber, Matthew; Belikov, Ruslan; Bendek, Eduardo

    2014-08-01

    Coronagraphic space telescopes require wavefront control systems for high-contrast imaging applications such as exoplanet direct imaging. High-actuator-count MEMS deformable mirrors (DM) are a key element of these wavefront control systems yet have not been flown in space long enough to characterize their on-orbit performance. The MEMS Deformable Mirror CubeSat Testbed is a conceptual nanosatellite demonstration of MEMS DM and wavefront sensing technology. The testbed platform is a 3U CubeSat bus. Of the 10 x 10 x 34.05 cm (3U) available volume, a 10 x 10 x 15 cm space is reserved for the optical payload. The main purpose of the payload is to characterize and calibrate the onorbit performance of a MEMS deformable mirror over an extended period of time (months). Its design incorporates both a Shack Hartmann wavefront sensor (internal laser illumination), and a focal plane sensor (used with an external aperture to image bright stars). We baseline a 32-actuator Boston Micromachines Mini deformable mirror for this mission, though the design is flexible and can be applied to mirrors from other vendors. We present the mission design and payload architecture and discuss experiment design, requirements, and performance simulations.

  14. Deformable mirror based remote focusing for fast three-dimensional microscopy

    NASA Astrophysics Data System (ADS)

    Zurauskas, Mantas; Frade, Maria; Booth, Martin

    2016-03-01

    We present a deformable mirror based remote focusing method for three-dimensional imaging in high-resolution microscopy systems. The method relies on predefined mirror mode arrays that are obtained during initial mirror training step with a low complexity wavefront-sensing module. The imaging plane can be refocused over distances over a hundred times greater than the original depth of field of the objective lens along the optical axis at millisecond rates. We will demonstrate the combination of the remote focusing method with spatiotemporally focused two-photon excitation applied to three-dimensional imaging of biological samples.

  15. Test results for an AOA-Xinetics grazing incidence x-ray deformable mirror

    NASA Astrophysics Data System (ADS)

    Lillie, Charles; Egan, Richard; Landers, Franklin; Cavaco, Jeffrey; Ezzo, Kevin; Khounsary, Ali

    2014-09-01

    X-ray telescopes use grazing incidence mirrors to focus X-ray photons from celestial objects. To achieve the large collecting areas required to image faint sources, thousands of thin, doubly curved mirrors are arranged in nested cylindrical shells to approximate a filled aperture. These mirrors require extremely smooth surfaces with precise figures to provide well-focused beams and small image spot sizes. The Generation-X telescope proposed by SAO would have a 12-meter aperture, a 50 m2 collecting area and 0.1 arc-second spatial resolution. This resolution would be obtained by actively controlling the mirror figure with piezoelectric actuators deposited on the back of each 0.4 mm thick mirror segment. To support SAO's Generation-X study, Northrop Grumman used internal funds to look at the feasibility of using Xinetics deformable mirror technologies to meet the Generation-X requirements. We designed and fabricated two 10 x 30 cm Platinum-coated silicon mirrors with 108 surface-parallel electrostrictive Lead Magnesium Niobate (PMN) actuators bonded to the mirror substrates. These mirrors were tested at optical wavelengths by Xinetics to assess the actuator's performance, but no funds were available for X-ray tests. In 2013, after receiving an invitation to evaluate the mirror's performance at Argonne National Laboratory, the mirrors were taken out of storage, refurbished, retested at Xinetics and transported to ANL for metrology measurements with a Long Trace Profilometer, a Fizeau laser interferometer, and X-ray tests. This paper describes the development and testing of the adaptive x-ray mirrors at AOAXinetics. Marathe, et al, will present the results of the tests at Argonne.

  16. A Novel Concept for a Deformable Membrane Mirror for Correction of Large Amplitude Aberrations

    NASA Technical Reports Server (NTRS)

    Moore, Jim; Patrick, Brian

    2006-01-01

    Very large, light weight mirrors are being developed for applications in space. Due to launch mass and volume restrictions these mirrors will need to be much more flexible than traditional optics. The use of primary mirrors with these characteristics will lead to requirements for adaptive optics capable of correcting wave front errors with large amplitude relatively low spatial frequency aberrations. The use of low modulus membrane mirrors actuated with electrostatic attraction forces is a potential solution for this application. Several different electrostatic membrane mirrors are now available commercially. However, as the dynamic range requirement of the adaptive mirror is increased the separation distance between the membrane and the electrodes must increase to accommodate the required face sheet deformations. The actuation force applied to the mirror decreases inversely proportional to the square of the separation distance; thus for large dynamic ranges the voltage requirement can rapidly increase into the high voltage regime. Experimentation with mirrors operating in the KV range has shown that at the higher voltages a serious problem with electrostatic field cross coupling between actuators can occur. Voltage changes on individual actuators affect the voltage of other actuators making the system very difficult to control. A novel solution has been proposed that combines high voltage electrodes with mechanical actuation to overcome this problem. In this design an array of electrodes are mounted to a backing structure via light weight large dynamic range flextensional actuators. With this design the control input becomes the separation distance between the electrode and the mirror. The voltage on each of the actuators is set to a uniform relatively high voltage, thus the problem of cross talk between actuators is avoided and the favorable distributed load characteristic of electrostatic actuation is retained. Initial testing and modeling of this concept

  17. Trans-reflection thermal driven deformable mirror with flexible bonding in high energy laser system

    NASA Astrophysics Data System (ADS)

    Ma, Xingkun; Huang, Lei; Gong, Mali; Xue, Qiao

    2014-09-01

    Deformable mirrors used in high energy laser system suffer from problems like the stress from adhesive solidification or the relatively expensive unit price of piezoceramic actuator. The thermal driven deformable mirror (TDDM) investigated here provided a promising prospect to solve these problems. Four scenarios of TDDM were studied and compared. Results showed that the trans-reflection TDDM with flexible bonding best met the requirement in practical use. The flexible bonding excluded the stress problem in the solidification of adhesives, trans-reflection brought about enough correction range, and the choice of thermo-electric cooler as actuator could greatly bring down the cost of adaptive optics apparatus as well.

  18. Reliability of MEMS deformable mirror technology used in adaptive optics imaging systems

    NASA Astrophysics Data System (ADS)

    Hartzell, Allyson L.; Cornelissen, Steven A.; Bierden, Paul A.; Lam, Charlie V.; Davis, Daniel F.

    2010-02-01

    Deformable mirror (DM) technology based on microelectromechanical systems (MEMS) technology produced by Boston Micromachines Corporation has been demonstrated to be an enabling component in a variety of adaptive optics applications such as high contrast imaging in astronomy, multi object adaptive optics, free-space laser communication, and microscopy. Many of these applications require DMs with thousands of actuators operating at frame rates up to 10 kHz for many years requiring sufficient device reliability to avoid device failures. In this paper we present improvements in MEMS deformable mirrors for reliability along with test data and device lifetime prediction that show trillions of actuator-cycles can be achieved without failures.

  19. Zinc selenide-based large aperture photo-controlled deformable mirror.

    PubMed

    Quintavalla, Martino; Bonora, Stefano; Natali, Dario; Bianco, Andrea

    2016-06-01

    Realization of large aperture deformable mirrors with a large density of actuators is important in many applications, and photo-controlled deformable mirrors (PCDMs) represent an innovation. Herein we show that PCDMs are scalable realizing a 2-inch aperture device based on a polycrystalline zinc selenide (ZnSe) as the photoconductive substrate and a thin polymeric reflective membrane. ZnSe is electrically characterized and analyzed through a model that we previously introduced. The PCDM is then optically tested, demonstrating its capabilities in adaptive optics. PMID:27244417

  20. Secure optical communication system utilizing deformable MEMS mirrors

    NASA Astrophysics Data System (ADS)

    Ziph-Schatzberg, Leah; Bifano, Thomas; Cornelissen, Steven; Stewart, Jason; Bleier, Zvi

    2009-02-01

    An optical communication system suitable for voice, data retrieval from remote sensors and identification is described. The system design allows operation at ranges of several hundred meters. The heart of the system is a modulated MEMS mirror that is electrostatically actuated and changes between a flat reflective state and a corrugated diffractive state. A process for mass producing these mirrors at low cost was developed and is described. The mirror was incorporated as a facet in a hollow retro-reflector, allowing temporal modulation of an interrogating beam and the return of the modulated beam to the interrogator. This system thus consists of a low power, small and light communication node with large (about 60°) angular extent. The system's range and pointing are determined by the interrogator /detector/demodulator (Transceiver) unit. The transceiver is comprised of an optical channel to establish line of sight communication, an interrogating laser at 1550nm, an avalanche photo diode to detect the return signal and electronics to drive the laser and demodulate the detected signal and convert it to an audio signal. A functional prototype system was built using a modified compact optical sight as the transceiver. Voice communication in free space was demonstrated. The design and test of major components and the complete system are discussed.

  1. Simulating wavefront correction via deformable mirrors at x-ray beamlines

    NASA Astrophysics Data System (ADS)

    Pardini, Tommaso; Poyneer, Lisa A.; Plinta, Audrey; Cavaco, Jeffrey L.; Pivovaroff, Michael J.

    2012-10-01

    Deformable mirrors (DMs) have been successfully used in astronomical adaptive optics at visible and near-infrared wavelengths, greatly reducing atmospheric-induced aberrations. Building upon the extensive techniques and methods developed for these applications, we propose to extend this capability to the soft and hard x-ray regime in order to take full advantage of the beam quality characteristic of new facilities such as the National Synchrotron Light Source (NSLS-II), and the Linac Coherent Light Source (LCLS). Achieving this goal challenges both current mirror manufacturing techniques and wavefront propagation modeling. Lawrence Livermore National Laboratory (LLNL), in collaboration with Northrop Grumman AOA Xinetics Inc., is currently developing an x-ray deformable mirror to correct for wave-front aberrations introduced along the beam path of a typical x-ray beamline. To model the expected performance of such a mirror, we have developed a simulation based on the wavefront propagation code PROPER. We will present the current implementation of the software, which models actuation of a deformable mirror and evaluates its effect on wavefront correction.

  2. Space active optics: in situ compensation of lightweight primary mirrors' deformations

    NASA Astrophysics Data System (ADS)

    Laslandes, M.; Ferrari, M.; Hugot, E.; Lemaitre, G.

    2010-12-01

    The need for both high quality images and light structures is a constant concern in the conception of space telescopes. The goal here is to determine how an active optics system could be embarked on a satellite in order to correct the wave front deformations of the optical train. The optical aberrations appearing in a space environment are due to mirrors' deformations, with three main origins: the thermal variations, the weightlessness conditions and the use of large weightlighted primary mirrors. We are developing a model of deformable mirror as minimalist as possible, especially in term of number of actuators, which is able to correct the first Zernike polynomials in a specified range of amplitude and precision. Flight constraints as weight, volume and power consumption are considered. Firstly, such a system is designed according to the equations from the elasticity theory: we determine the geometrical and mechanical characteristics of the mirror, the location of the forces to be applied and the way to apply them. Then the concept is validated with a Finite Element Analysis, allowing to optimize the system by taking into account parameters absent from the theory. At the end, the mirror will be realized and characterized in a representative optical configuration.

  3. Structural design and mitigation of mirror deformations in lunar-based telescopes

    SciTech Connect

    Luz, P.L.

    1994-11-01

    Structural design and analysis of the optical systems for lunar-based telescopes is a challenging task. A driving concern of the Lunar Ultraviolet Telescope Experiment (LUTE) preliminary design study was the degradation of the LUTE optical figure due to thermal deformations, during a temperature cycle of 65 to 265 K at the reference 40 deg latitude, 0 deg longitude landing site. In addressing this task, temperature effects were characterized, and primary-mirror thermal deformations calculated for use in the optical analyses. Trade studies evaluated the qualitative performance of various design schemes. Results indicated that statically determinate mirror supports with bottom-mounted flexures created less optical disturbance under thermal loading than mirror supports at the inner or outer periphery. Another trade indicated that a telescope`s baseplate must be athermalized with respect to the mirrors by matching thermal distortion coefficients. A comparison of three materials for the primary mirror predicted that silicon carbide would be the best material for resisting thermally induced figure deformations on the moon. 15 refs.

  4. Adaptive optics with a magnetic deformable mirror: applications in the human eye

    NASA Astrophysics Data System (ADS)

    Fernandez, Enrique J.; Vabre, Laurent; Hermann, Boris; Unterhuber, Angelika; Povazay, Boris; Drexler, Wolfgang

    2006-10-01

    A novel deformable mirror using 52 independent magnetic actuators (MIRAO 52, Imagine Eyes) is presented and characterized for ophthalmic applications. The capabilities of the device to reproduce different surfaces, in particular Zernike polynomials up to the fifth order, are investigated in detail. The study of the influence functions of the deformable mirror reveals a significant linear response with the applied voltage. The correcting device also presents a high fidelity in the generation of surfaces. The ranges of production of Zernike polynomials fully cover those typically found in the human eye, even for the cases of highly aberrated eyes. Data from keratoconic eyes are confronted with the obtained ranges, showing that the deformable mirror is able to compensate for these strong aberrations. Ocular aberration correction with polychromatic light, using a near Gaussian spectrum of 130 nm full width at half maximum centered at 800 nm, in five subjects is accomplished by simultaneously using the deformable mirror and an achromatizing lens, in order to compensate for the monochromatic and chromatic aberrations, respectively. Results from living eyes, including one exhibiting 4.66 D of myopia and a near pathologic cornea with notable high order aberrations, show a practically perfect aberration correction. Benefits and applications of simultaneous monochromatic and chromatic aberration correction are finally discussed in the context of retinal imaging and vision.

  5. Optimization of electrode geometry and piezoelectric layer thickness of a deformable mirror

    NASA Astrophysics Data System (ADS)

    Kruchenko, Alexey V.; Nováková, Kateřina; Mokrý, Pavel

    2013-04-01

    Deformable mirrors are the most commonly used wavefront correctors in adaptive optics systems. Nowadays, many applications of adaptive optics to astronomical telescopes, high power laser systems, and similar fast response optical devices require large diameter deformable mirrors with a fast response time and high actuator stroke. In order to satisfy such requirements, deformable mirrors based on piezoelectric layer composite structures have become a subject of intense scientific research during last two decades. In this paper, we present an optimization of several geometric parameters of a deformable mirror that consists of a nickel reflective layer deposited on top of a thin lead zirconate titanate (PZT) piezoelectric disk. Honeycomb structure of gold electrodes is deposited on the bottom of the PZT layer. The analysis of the optimal thickness ratio between the PZT and nickel layers is performed to get the maximum actuator stroke using the finite element method. The effect of inter-electrode distance on the actuator stroke and influence function is investigated. Applicability and manufacturing issues are discussed.

  6. Interferometric nulling limits with tip-tilt-piston deformable mirrors and a pinhole spatial filter array

    NASA Astrophysics Data System (ADS)

    Hicks, Brian A.; Chakrabarti, Supriya; Cook, Timothy A.

    2015-01-01

    We explore the use of hexagonal segment tip-tilt-piston deformable mirrors alone and paired with pinhole spatial filter arrays for high-order wavefront correction of nulling interferometers used for visible light study of exoplanetary systems at 107 to 1010 contrast within regions extending ˜0.1 to 6 arc s from a parent star. A similar system has been proposed using a single-mode fiber array as an alternative to using multiple deformable mirrors to correct both phase aberrations and balance electric field amplitude, the benefit being drastically reduced component and control complexity. Performance is compared using measured deformable mirror data for hexagonal arrays consisting of a number of rings NR=2 to 18, emphasizing the trade between throughput and the additional contrast gained from suppressing wavefront errors introduced by the deformable mirror at spatial frequencies Λ≥NR that are otherwise present in the image at corresponding field locations. Taking into account effects of loss of throughput and vignetting, the nulled signal-to-noise ratio is shown to improve for filtered systems in the outer portion of the field of view. Modeled performance shows no significant change in signal-to-noise in the inner field of view.

  7. Theory and computation of three cosmic origin spectrograph aspheric gratings recorded with a multimode deformable mirror.

    PubMed

    Duban, M

    1999-03-01

    The theory of three Cosmic Origin Spectrograph holographic gratings recorded with a deformable plane mirror is presented. Their working conditions are severe, since they have to correct the strong spherical aberration and the field astigmatism of the Hubble Space Telescope. Recorded on aspherized substrates, the gratings produce images that are diffraction limited with regard to spectral resolution. PMID:18305717

  8. Concept and modeling analysis of a high fidelity multimode deformable mirror.

    PubMed

    Zhou, Chao; Li, Yun; Wang, Anding; Xing, Tingwen

    2015-06-10

    Conventional deformable mirrors (DM) cannot meet the requirement of aberration controlling for advanced lithography tools. This paper illustrates an approach using the property that deformation of a thin plate is similar to optical modes to realize a high fidelity multimode deformable mirror whose deformation has characteristics of optical aberration modes. The way to arrange actuators is also examined. In this paper, a 36-actuator deformable mirror is taken as an example to generate low-order Zernike modes. The result shows that this DM generates the fourth fringe Zernike mode (Z4) defocus, and primary aberration Z5-Z8 with an error less than 0.5%, generates the fifth-order aberration Z10-Z14, and generates the seventh-order aberration Z17-Z20 with an error less than 1.1%. The high fidelity replication of the Zernike mode indicates that the DM satisfies the demand of controlling aberrations corresponding to the first 20 Zernike modes in an advanced lithography tool. PMID:26192845

  9. Analysis investigation of supporting and restraint conditions on the surface deformation of a collimator primary mirror

    NASA Astrophysics Data System (ADS)

    Chan, Chia-Yen; You, Zhen-Ting; Huang, Bo-Kai; Chen, Yi-Cheng; Huang, Ting-Ming

    2015-09-01

    For meeting the requirements of the high-precision telescopes, the design of collimator is essential. The diameter of the collimator should be larger than that of the target for the using of alignment. Special supporting structures are demanded to reduce the deformation of gravity and to control the surface deformation induced by the mounting force when inspecting large-aperture primary mirrors. By using finite element analysis, a ZERODUR® mirror of a diameter of 620 mm will be analyzed to obtain the deformation induced by the supporting structures. Zernike polynomials will also be adopted to fit the optical surface and separate corresponding aberrations. Through the studies under different boundary conditions and supporting positions of the inner ring, it is concluded that the optical performance will be excellent under a strong enough supporter.

  10. Mirror actively deformed and regulated for applications in space: design and performance

    NASA Astrophysics Data System (ADS)

    Laslandes, Marie; Hugot, Emmanuel; Ferrari, Marc; Hourtoule, Claire; Singer, Christian; Devilliers, Christophe; Lopez, Céline; Chazallet, Frédéric

    2013-09-01

    The need for both high quality images and lightweight structures is one of the main drivers in space telescope design. An efficient wavefront control system will become mandatory in future large observatories, retaining performance while relaxing specifications in the global system's stability. We present the mirror actively deformed and regulated for applications in space project, which aims to demonstrate the applicability of active optics for future space instrumentation. It has led to the development of a 24-actuator, 90-mm-diameter active mirror, able to compensate for large lightweight primary mirror deformations in the telescope's exit pupil. The correcting system has been designed for expected wavefront errors from 3-m-class lightweight primary mirrors, while also taking into account constraints for space use. Finite element analysis allowed an optimization of the system in order to achieve a precision of correction better than 10 nm rms. A dedicated testbed has been designed to fully characterize the integrated system performance in representative operating conditions. It is composed of: a telescope simulator, an active correction loop, a point spread function imager, and a Fizeau interferometer. All conducted tests demonstrated the correcting mirror performance and has improved this technology maturity to a TRL4.

  11. The thin mirror deformation and stress distribution analysis based on different influence functions

    NASA Astrophysics Data System (ADS)

    Wang, Hongqiao; Fan, Bin; Wu, Yongqian; Liu, Haitao; Liu, Rong

    2014-08-01

    The active support technique can be applied in the fabrication of large thin meniscus mirror. It can reduce the grinding and polishing difficulty for thin mirror. Compare between two kinds of influence function, we correct the Zernike 5th, 6th, 10th and 11th mode deformation. The low-order Zernike modes which are prone to appearing during large primary mirror processing are revised with active support technology. Influence functions are expressed with Z coordinate value and Zernike coefficient of surface shape. This paper reports that respectively adopting different influence functions to solve correction forces and the correction forces compensates specific Zernike modes of mirror deformation. After comparing the PV and RMS values of amendatory residual of surface shape, we analyze the effect of different correction forces to the biggest stress on the underside of the primary mirror. We compare the two methods based on the PV and RMS values of the residual error and the Max-stress. Gain a conclusion that correction forces obtained from Z coordinate value of surface shape is superior to the one obtained from the Zernike coefficient of surface shape.

  12. Adaptive Optics: Arroyo Simulation Tool and Deformable Mirror Actuation Using Golay Cells

    NASA Technical Reports Server (NTRS)

    Lint, Adam S.

    2005-01-01

    The Arroyo C++ libraries, written by Caltech post-doc student Matthew Britton, have the ability to simulate optical systems and atmospheric signal interference. This program was chosen for use in an end-to-end simulation model of a laser communication system because it is freely distributed and has the ability to be controlled by a remote system or "smart agent." Proposed operation of this program by a smart agent has been demonstrated, and the results show it to be a suitable simulation tool. Deformable mirrors, as a part of modern adaptive optics systems, may contain thousands of tiny, independently controlled actuators used to modify the shape of the mirror. Each actuator is connected to two wires, creating a cumbersome and expensive device. Recently, an alternative actuation method that uses gas-filled tubes known as Golay cells has been explored. Golay cells, operated by infrared lasers instead of electricity, would replace the actuator system thereby creating a more compact deformable mirror. The operation of Golay cells and their ability to move a deformable mirror in excess of the required 20 microns has been demonstrated. Experimentation has shown them to be extremely sensitive to pressure and temperature, making them ideal for use in a controlled environment.

  13. Demonstration of a 17 cm robust carbon fiber deformable mirror for adaptive optics

    SciTech Connect

    Ammons, S M; Hart, M; Coughenour, B; Romeo, R; Martin, R; Rademacher, M

    2011-09-12

    Carbon-fiber reinforced polymer (CFRP) composite is an attractive material for fabrication of optics due to its high stiffness-to-weight ratio, robustness, zero coefficient of thermal expansion (CTE), and the ability to replicate multiple optics from the same mandrel. We use 8 and 17 cm prototype CFRP thin-shell deformable mirrors to show that residual CTE variation may be addressed with mounted actuators for a variety of mirror sizes. We present measurements of surface quality at a range of temperatures characteristic of mountaintop observatories. For the 8 cm piece, the figure error of the Al-coated reflective surface under best actuator correction is {approx}43 nm RMS. The 8 cm mirror has a low surface error internal to the outer ring of actuators (17 nm RMS at 20 C and 33 nm RMS at -5 C). Surface roughness is low (< 3 nm P-V) at a variety of temperatures. We present new figure quality measurements of the larger 17 cm mirror, showing that the intra-actuator figure error internal to the outer ring of actuators (38 nm RMS surface with one-third the actuator density of the 8 cm mirror) does not scale sharply with mirror diameter.

  14. Demonstration of 17 cm robust carbon fiber deformable mirror for adaptive optics

    NASA Astrophysics Data System (ADS)

    Ammons, S. Mark; Hart, Michael; Coughenour, Blake; Romeo, Robert; Martin, Robert; Rademacher, Matt

    2011-10-01

    Carbon-fiber reinforced polymer (CFRP) composite is an attractive material for fabrication of optics due to its high stiffness-to-weight ratio, robustness, zero coefficient of thermal expansion (CTE), and the ability to replicate multiple optics from the same mandrel. We use 8 and 17 cm prototype CFRP thin-shell deformable mirrors to show that residual CTE variation may be addressed with mounted actuators for a variety of mirror sizes. We present measurements of surface quality at a range of temperatures characteristic of mountaintop observatories. For the 8 cm piece, the figure error of the Al-coated reflective surface under best actuator correction is ~43 nm RMS. The 8 cm mirror has a low surface error internal to the outer ring of actuators (17 nm RMS at 20°C and 33 nm RMS at -5°C). Surface roughness is low (< 3 nm P-V) at a variety of temperatures. We present new figure quality measurements of the larger 17 cm mirror, showing that the intra-actuator figure error internal to the outer ring of actuators (38 nm RMS surface with one-third the actuator density of the 8 cm mirror) does not scale sharply with mirror diameter.

  15. Scalable stacked array piezoelectric deformable mirror for astronomy and laser processing applications

    SciTech Connect

    Wlodarczyk, Krystian L. Maier, Robert R. J.; Hand, Duncan P.; Bryce, Emma; Hutson, David; Kirk, Katherine; Schwartz, Noah; Atkinson, David; Beard, Steven; Baillie, Tom; Parr-Burman, Phil; Strachan, Mel

    2014-02-15

    A prototype of a scalable and potentially low-cost stacked array piezoelectric deformable mirror (SA-PDM) with 35 active elements is presented in this paper. This prototype is characterized by a 2 μm maximum actuator stroke, a 1.4 μm mirror sag (measured for a 14 mm × 14 mm area of the unpowered SA-PDM), and a ±200 nm hysteresis error. The initial proof of concept experiments described here show that this mirror can be successfully used for shaping a high power laser beam in order to improve laser machining performance. Various beam shapes have been obtained with the SA-PDM and examples of laser machining with the shaped beams are presented.

  16. High-aspect-ratio line focus for an x-ray laser by a deformable mirror

    SciTech Connect

    Yoon, G.; Jitsuno, T.; Kato, Y.; Nakatsuka, M.

    1997-02-01

    A high-aspect-ratio line focus is required on a plane target in x-ray laser experiments for obtaining a high gain-length product. Inherent wave-front aberrations in line-focusing optics, which consist of a cylindrical lens and a spherical lens, are discussed with respect to beam diameter. The nonuniformity of the linewidth that is due to the aberrations is also calculated by the ABCD matrix method. A deformable mirror of a continuous plate type with a diameter of 185 mm provides an adequate wave-front distribution for compensating for the wave-front aberration. The wave-front control by the deformable mirror realizes a fine linewidth of 25 {mu}m and 18.2 mm long, corresponding to the aspect ratio of 728. The linewidth is three times the diffraction limit. The intensity distribution along the line focus is also improved. {copyright} 1997 Optical Society of America

  17. High-aspect-ratio line focus for an x-ray laser by a deformable mirror.

    PubMed

    Yoon, G Y; Jitsuno, T; Kato, Y; Nakatsuka, M

    1997-02-01

    A high-aspect-ratio line focus is required on a plane target in x-ray laser experiments for obtaining a high gain-length product. Inherent wave-front aberrations in line-focusing optics, which consist of a cylindrical lens and a spherical lens, are discussed with respect to beam diameter. The nonuniformity of the linewidth that is due to the aberrations is also calculated by the ABCD matrix method. A deformable mirror of a continuous plate type with a diameter of 185 mm provides an adequate wave-front distribution for compensating for the wave-front aberration. The wave-front control by the deformable mirror realizes a fine linewidth of 25 microm and 18.2 mm long, corresponding to the aspect ratio of 728. The linewidth is three times the diffraction limit. The intensity distribution along the line focus is also improved. PMID:18250748

  18. Woofer-tweeter deformable mirror control for closed-loop adaptive optics: theory and practice

    NASA Astrophysics Data System (ADS)

    Gavel, Donald; Norton, Andrew

    2014-08-01

    Deformable mirrors with very high order correction generally have smaller dynamic range of motion than what is required to correct seeing over large aperture telescopes. As a result, systems will need to have an architecture that employs two deformable mirrors in series, one for the low-order but large excursion parts of the wavefront and one for the finer and smaller excursion components. The closed-loop control challenge is to a) keep the overall system stable, b) avoid the two mirrors using control energy to cancel each others correction, c) resolve actuator saturations stably, d) assure that on average the mirrors are each correcting their assigned region of spatial frequency space. We present the control architecture and techniques for assuring that it is linear and stable according to the above criteria. We derived the analytic forms for stability and performance and show results from simulations and on-sky testing using the new ShaneAO system on the Lick 3-meter telescope.

  19. Lightweight deformable mirrors for ground- and space-based imaging systems

    NASA Astrophysics Data System (ADS)

    Kendrew, Sarah

    2006-08-01

    The next generation of ground- and space-based astronomical observatories will generate an increased requirement for lightweight and robust deformable optics. In space ultra-lightweight actively controlled mirrors will enable a continuing increase of aperture sizes, whilst large adaptive mirrors will become increasingly standard features in the optical design of adaptive optics-optimised Extremely Large Telescopes on the ground. This thesis presents results from a project to design, manufacture and test a prototype active mirror in a nickel-carbon fibre reinforced polymer (CFRP), which has been suggested in the literature to be a promising candidate material for such applications. Extensive finite element analysis results from gravitational sag and thermal models, as well as finite element-based predictions of the central actuator influence function profile, are presented. The main problems were encountered as a result of the in-mold nickel coating process, which resulted in residual form errors, and poor design of the support structures, leading to deterioration of the mirror surface quality. No fundamental reason ruling this material out for the use of precision deformable optics was identified. The finite element analysis results show significant promise for increased use of the method in optical design, as well as in integrated optical simulations for Extremely Large Telescopes.

  20. A 1-metre Ni coated CFRP demonstrator for large deformable mirrors

    NASA Astrophysics Data System (ADS)

    Thompson, Samantha J.; Doel, Peter; Brooks, David; Strangwood, Martin

    We present results from our current project to develop an alternative substrate for large deformable mirrors, particularly with the European Extremely Large Telescope (E-ELT) in mind. Our mirror substrate consists of a carbon-fibre reinforced polymer (CFRP) core encapsulated in a thick (50µm) coating of nickel; the coating entirely covers the CFRP front, back and edges. The benefits of CFRP are: that it has high tensile strength, making it exceptionally resistant to breakage and able to withstand high inter-actuator forces; that it can be fabricated in large sections, allowing the production of a 2.6 m monolithic mirror, simplifying system control and eliminating additional diffraction/scattering introduced by segmented mirror systems; its low density (< 1800 kgm-3 for a Ni coated substrate). By the end of summer this year (2009) we aim to have constructed a 19 cm diameter fully actuated (37 piezo-stack actuators on a 29 mm triangular grid) prototype and a 1.0 m diameter substrate mounted on a static set of points to demonstrate the scalability of the technology. We discuss the processes involved in forming a Ni-CFRP mirror, the results obtained so far and a current status update.

  1. Swept source optical coherence tomography Gabor fusion splicing technique for microscopy of thick samples using a deformable mirror.

    PubMed

    Costa, Christopher; Bradu, Adrian; Rogers, John; Phelan, Pauline; Podoleanu, Adrian

    2015-01-01

    We present a swept source optical coherence tomography (OCT) system at 1060 nm equipped with a wavefront sensor at 830 nm and a deformable mirror in a closed-loop adaptive optics (AO) system. Due to the AO correction, the confocal profile of the interface optics becomes narrower than the OCT axial range, restricting the part of the B-scan (cross section) with good contrast. By actuating on the deformable mirror, the depth of the focus is changed and the system is used to demonstrate Gabor filtering in order to produce B-scan OCT images with enhanced sensitivity throughout the axial range from a Drosophila larvae. The focus adjustment is achieved by manipulating the curvature of the deformable mirror between two user-defined limits. Particularities of controlling the focus for Gabor filtering using the deformable mirror are presented. PMID:25588163

  2. Swept source optical coherence tomography Gabor fusion splicing technique for microscopy of thick samples using a deformable mirror

    NASA Astrophysics Data System (ADS)

    Costa, Christopher; Bradu, Adrian; Rogers, John; Phelan, Pauline; Podoleanu, Adrian

    2015-01-01

    We present a swept source optical coherence tomography (OCT) system at 1060 nm equipped with a wavefront sensor at 830 nm and a deformable mirror in a closed-loop adaptive optics (AO) system. Due to the AO correction, the confocal profile of the interface optics becomes narrower than the OCT axial range, restricting the part of the B-scan (cross section) with good contrast. By actuating on the deformable mirror, the depth of the focus is changed and the system is used to demonstrate Gabor filtering in order to produce B-scan OCT images with enhanced sensitivity throughout the axial range from a Drosophila larvae. The focus adjustment is achieved by manipulating the curvature of the deformable mirror between two user-defined limits. Particularities of controlling the focus for Gabor filtering using the deformable mirror are presented.

  3. Variable focal length on-and off-axis deformable concave and convex mirror and its application for thermal lens compensation.

    SciTech Connect

    Ramsey, Marc; Smith, Ian C.; Rambo, Patrick K.; Headley, Daniel Ignacio; Porter, John Larry, Jr.; Schwarz, Jens

    2005-07-01

    We have improved deformable mirror approach to allow good parabolic deformation for efficient thermal lens compensation. Our design uses an annulus to push onto the back surface of a flat mirror substrate, simply supported at the outer edge, thereby creating a parabolic deformation within the encircled area. We built an assembly using a 25.4 mm diameter, 1 mm thick mirror with a wedge of less than 10 arc seconds that was deformed with a 12 mm diameter annulus at the back of the mirror. Using a Shack-Hartman wavefront sensor we performed careful measurements to characterize the performance of the mirrors.

  4. The deformable secondary mirror of VLT: final electro-mechanical and optical acceptance test results

    NASA Astrophysics Data System (ADS)

    Briguglio, Runa; Biasi, Roberto; Xompero, Marco; Riccardi, Armando; Andrighettoni, Mario; Pescoller, Dietrich; Angerer, Gerald; Gallieni, Daniele; Vernet, Elise; Kolb, Johann; Arsenault, Robin; Madec, Pierre-Yves

    2014-07-01

    The Deformable Secondary Mirror (DSM) for the VLT ended the stand-alone electro-mechanical and optical acceptance process, entering the test phase as part of the Adaptive Optics Facility (AOF) at the ESO Headquarter (Garching). The VLT-DSM currently represents the most advanced already-built large-format deformable mirror with its 1170 voice-coil actuators and its internal metrology based on co-located capacitive sensors to control the shape of the 1.12m-diameter 2mm-thick convex shell. The present paper reports the final results of the electro-mechanical and optical characterization of the DSM executed in a collaborative effort by the DSM manufacturing companies (Microgate s.r.l. and A.D.S. International s.r.l.), INAF-Osservatorio Astrofisico di Arcetri and ESO. The electro-mechanical acceptance tests have been performed in the company premises and their main purpose was the dynamical characterization of the internal control loop response and the calibration of the system data that are needed for its optimization. The optical acceptance tests have been performed at ESO (Garching) using the ASSIST optical test facility. The main purpose of the tests are the characterization of the optical shell flattening residuals, the corresponding calibration of flattening commands, the optical calibration of the capacitive sensors and the optical calibration of the mirror influence functions.

  5. Characterization of a bimorph deformable mirror using stroboscopic phase-shifting interferometry

    PubMed Central

    Horsley, David A.; Park, Hyunkyu; Laut, Sophie P.; Werner, John S.

    2008-01-01

    The static and dynamic characteristics of a bimorph deformable mirror (DM) for use in an adaptive optics system are described. The DM is a 35-actuator device composed of two disks of lead magnesium niobate (PMN), an electrostrictive ceramic that produces a mechanical strain in response to an imposed electric field. A custom stroboscopic phase-shifting interferometer was developed to measure the deformation of the mirror in response to applied voltage. The ability of the mirror to replicate optical aberrations described by the Zernike polynomials was tested as a measure of the mirror’s static performance. The natural frequencies of the DM were measured up to 20 kHz using both stroboscopic interferometry as well as a commercial laser Doppler vibrometer (LDV). Interferometric measurements of the DM surface profile were analyzed by fitting the surface with mode-shapes predicted using classical plate theory for an elastically supported disk. The measured natural frequencies were found to be in good agreement with the predictions of the theoretical model. PMID:19122798

  6. Method of analysis for determining and correcting mirror deformation due to gravity

    NASA Astrophysics Data System (ADS)

    Clark, James H.; Ernesto Penado, F.

    2014-01-01

    The Navy Precision Optical Interferometer, located near Flagstaff, Arizona, is a ground-based interferometer that collects, transports, and modulates stellar radiation from up to six primary flat collectors, known as siderostats, through a common vacuum relay system to a combiner. In the combiner, the modulated beams are superimposed, fringes obtained, and data recorded for further analysis to produce precise star positions or stellar details. The current number of observable stellar objects for the astrometric interferometer can increase from 6000 to at least 47,000 with the addition of full-aperture 20-deg down-tilting beam compressors in each optical train. Such an aperture increase, from the current 12.5 to 35 cm, opens the sky to many additional and fainter stars. Engineering analysis of our beam compressor primary mirror shows that the maximum allowable sag, 21 nm, occurs prematurely at 2.8-deg down-tilt angle. Furthermore, at the operational down-tilt angle of 20 deg, the wavefront deformation increases to 155 nm. We present a finite element analysis technique and design modification concept to reduce tilt-induced deformation on the mirror surface. This work is a first pass to determine the feasibility for a mechanical solution path forward. From this analysis, we found that four outwardly applied 17.8-N forces on the rear surface of the mirror could reduce sag from 155 to 32 nm at 20-deg down-tilt angle.

  7. Evaluation of control laws and actuator locations for control systems applicable to deformable astronomical telescope mirrors

    NASA Technical Reports Server (NTRS)

    Ostroff, A. J.

    1973-01-01

    Some of the major difficulties associated with large orbiting astronomical telescopes are the cost of manufacturing the primary mirror to precise tolerances and the maintaining of diffraction-limited tolerances while in orbit. One successfully demonstrated approach for minimizing these problem areas is the technique of actively deforming the primary mirror by applying discrete forces to the rear of the mirror. A modal control technique, as applied to active optics, has previously been developed and analyzed. The modal control technique represents the plant to be controlled in terms of its eigenvalues and eigenfunctions which are estimated via numerical approximation techniques. The report includes an extension of previous work using the modal control technique and also describes an optimal feedback controller. The equations for both control laws are developed in state-space differential form and include such considerations as stability, controllability, and observability. These equations are general and allow the incorporation of various mode-analyzer designs; two design approaches are presented. The report also includes a technique for placing actuator and sensor locations at points on the mirror based upon the flexibility matrix of the uncontrolled or unobserved modes of the structure. The locations selected by this technique are used in the computer runs which are described. The results are based upon three different initial error distributions, two mode-analyzer designs, and both the modal and optimal control laws.

  8. A Novel Microprocessor-Controlled High-Voltage Driver for Deformable Mirrors

    NASA Astrophysics Data System (ADS)

    Heuck, H.-M.; Buske, I.; Buschmann, U.; Krause, H.; Wittrock, U.

    Genetic algorithms have found widespread use in adaptive optics. One important advantage compared to the matrix inversion method is that it is not necessary to measure the wavefront of the optical beam on which the deformable mirror acts. Instead, any signal, that is monotonic increasing with the quality of the desired wavefront, is sufficient as a feedback signal. Often, this signal derives from a power-in-the-bucket measurement in the far-field of the beam. In coherent control of chemical reactions with temporally shaped femtosecond laser pulses the signal derives from the rate at which the desired chemical is produced. In our adaptive optics experiments we use micro-machined silicon membrane mirrors with up to 59 electrostatic actuators. We have developed a microprocessor-controlled highvoltage driver for up to 60 channels because we could not find a suitable driver on the market. The driver is a fully self-contained unit that only needs input power and communicates with a personal computer via a USB interface. It is especially suited for controlling adaptive mirrors with a genetic algorithm. The driver can store up to 100 voltage patterns, apply them sequentially to the mirror, store up to 4 feedback signals for each voltage pattern, and relay these feedback signals back to the host computer. We will discuss performance issues and tradeoffs like speed, bit resolution, and number of electrodes in our presentation.

  9. MAGNETIC LIQUID DEFORMABLE MIRRORS FOR ASTRONOMICAL APPLICATIONS: ACTIVE CORRECTION OF OPTICAL ABERRATIONS FROM LOWER-GRADE OPTICS AND SUPPORT SYSTEM

    SciTech Connect

    Borra, E. F.

    2012-08-01

    Deformable mirrors are increasingly used in astronomy. However, they still are limited in stroke for active correction of high-amplitude optical aberrations. Magnetic liquid deformable mirrors (MLDMs) are a new technology that has the advantages of high-amplitude deformations and low costs. In this paper, we demonstrate extremely high strokes and interactuator strokes achievable by MLDMs which can be used in astronomical instrumentation. In particular, we consider the use of such a mirror to suggest an interesting application for the next generation of large telescopes. We present a prototype 91 actuator deformable mirror made of a magnetic liquid (ferrofluid). This mirror uses a technique that linearizes the response of such mirrors by superimposing a large and uniform magnetic field on the magnetic field produced by an array of small coils. We discuss experimental results that illustrate the performance of MLDMs. A most interesting application of MLDMs comes from the fact they could be used to correct the aberrations of large and lower optical quality primary mirrors held by simple support systems. We estimate basic parameters of the needed MLDMs, obtaining reasonable values.

  10. Time-dependent deformation of surface geometry on light weight and thermally stable CFRP mirror in humid environment

    NASA Astrophysics Data System (ADS)

    Arao, Yoshihiko; Koyanagi, Jun; Utsunomiya, Shin; Takeda, Shin-ichi; Kawada, Hiroyuki

    2010-07-01

    CFRP (Carbon Fiber Reinforced Plastics) is the ideal material for space based mirror due to its low thermal expansion, and high specific modulus. To expand the use of CFRP, we investigated the long-term stability of CFRP under humid environment. CFRP mirror was made as precise as possible by using special class of material and adopting particular design techniques. Dimensional stability of CFRP mirror was evaluated by nano-scale measurement. The factors which cause out-of-plane deformation of the mirror is discussed.

  11. Real-time open-loop control of a 1024-actuator MEMS deformable mirror

    NASA Astrophysics Data System (ADS)

    Blain, Célia; Conan, Rodolphe; Bradley, Colin; Guyon, Olivier; Gamroth, Darryl; Nash, Reston

    2010-07-01

    This article reports the progress made at the University of Victoria AO Lab, regarding the realtime open-loop control of a 1024-actuator MEMS deformable mirror (DM). The setup is an hybrid woofer-tweeter/open-loop bench. A tip-tilt mirror and a woofer DM (a 57-actuator CILAS DM) are driven in closed-loop while a 1024-actuator MEMS DM is utilized on a parallel open-loop path. Previous work shows that open-loop control providing low residual error (with frozen Kolmogorov turbulence) can be obtained without the need of DM modelling. A preliminary methodical calibration of the DM is employed instead. The MEMS electronics were upgraded to an update rate of 500 Hz and the experiment lays the groundwork for showing how these performances can also be achieved on the bench with dynamic turbulence (created with custom hot air turbulence generators). The current status of the experiment and the next milestones are presented.

  12. Low order adaptive optics on Z-Beamlet using a single actuator deformable mirror

    NASA Astrophysics Data System (ADS)

    Schwarz, Jens; Ramsey, Marc; Smith, Ian; Headley, Daniel; Porter, John

    2006-08-01

    The Z-Beamlet laser at Sandia National Laboratories can perform a full system shot every 3-4 h. This shot rate is limited by thermal aberrations that result from the flashlamp pumped Nd:phosphate amplifier slabs. The lowest order as well as the strongest aberration is of cylindrical shape. Therefore, a single actuator deformable mirror assembly for correction of cylindrical aberration was developed. Mirror performance was modeled using finite element analysis and showed good agreement with derived analytical expressions. Quantitative measurements were performed with an interferometer and thermal lens compensation was achieved in the Z-Beamlet laser system leading to an increased shot rate of one in every 2 h.

  13. Effect of the particular temperature field on a National Ignition Facility deformable mirror

    NASA Astrophysics Data System (ADS)

    Bian, Qi; Huang, Lei; Ma, Xingkun; Xue, Qiao; Gong, Mali

    2016-09-01

    The changes caused by temperature in the surface shape of a deformable mirror used at the National Ignition Facility has been investigated previously. In this paper the temperature induced surface shape under different temperature fields is further studied. We find that the changes of the peak and valley (PV) or root-mean-square (RMS) value rely on the temperature gradient as well as the difference between the mirror and the environment with a certain rule. This work analyzes these quantitative relationship, using the finite element method. Some experiments were carried out to verify the analysis results. The conclusion provides guidance to minimize the effect of the temperature field on the surface shape. Considerations about how to improve the temperature induced faceplate in actual work are suggested finally.

  14. Compensation of Gravity-Induced Structural Deformations on a Beam- Waveguide Antenna Using a Deformable Mirror

    NASA Technical Reports Server (NTRS)

    Imbriale, W. A.; Moore, M.; Rochblatt, D. J.; Veruttipong, W.

    1995-01-01

    At the NASA Deep Space Network (DSN) Goldstone Complex, a 34-meter- diameter beam-waveguide antenna, DSS-13, was constructed in 1988-1990 and has become an integral part of an advanced systems program and a test bed for technologies being developed to introduce Ka-band (32 GHz) frequencies into the DSN. A method for compensating the gravity- induced structural deformations in this large antenna is presented.

  15. Woofer-tweeter adaptive optics in very strong turbulence using a magnetic-liquid deformable mirror

    NASA Astrophysics Data System (ADS)

    Brousseau, Denis; Véran, Jean-Pierre; Thibault, Simon; Borra, Ermanno F.; F.-Boivin, Simon.

    2012-07-01

    We present progress towards the development of a woofer-tweeter adaptive optics (AO) system using the first 37 actuators of a 91-actuator magnetic-liquid deformable mirror (MLDM) and a magnetic 97-actuator DM from ALPAO. The MLDM, which has both very large single-actuator and inter-actuator strokes, but a low bandwidth, is used as woofer, whereas the high bandwidth and lower stroke ALPAO DM is used as tweeter. The ALPAO DM should improve the bandwidth of the MLDM while the MLDM will allow correction of strong aberrations.

  16. The use of a high-order MEMS deformable mirror in the Gemini Planet Imager

    SciTech Connect

    Poyneer, L A; Bauman, B; Cornelissen, S; Jones, S; Macintosh, B; Palmer, D; Isaacs, J

    2010-12-17

    We briefly review the development history of the Gemini Planet Imager's 4K Boston Micromachines MEMS deformable mirror. We discuss essential calibration steps and algorithms to control the MEMS with nanometer precision, including voltage-phase calibration and influence function characterization. We discuss the integration of the MEMS into GPI's Adaptive Optics system at Lawrence Livermore and present experimental results of 1.5 kHz closed-loop control. We detail mitigation strategies in the coronagraph to reduce the impact of abnormal actuators on final image contrast.

  17. Measurement of thermal deformation of an engine piston using a conical mirror and ESPI

    NASA Astrophysics Data System (ADS)

    Albertazzi, Armando, Jr.; Melao, Iza; Devece, Eugenio

    1998-07-01

    An experimental technique is developed to measure the radial displacement component of cylindrical surfaces using a conical mirror for normal illumination and observation. Single illumination ESPI is used to obtain fringe patterns related to the radial displacement field. Some data processing strategies are presented and discussed to properly extract the measurement data. Data reduction algorithms are developed to quantify and compensate the rigid body displacements: translations and rotations. The displacement component responsible for shape distortion (deformation) can be separated from the total displacement field. The thermal radial deformation of an aluminum engine piston with a steel sash is measured by this technique. A temperature change of about 2 degrees Celsius was applied to the engine piston by means of an electrical wire wrapped up in the first engine piston grove. The fringe patterns are processed and the results are presented as polar graphics and 3D representation. The main advantages and limitations of the developed technique are discussed.

  18. Restraint deformation and corrosion protection of gold deposited aluminum mirrors for cold optics of mid-infrared instruments

    NASA Astrophysics Data System (ADS)

    Uchiyama, Mizuho; Miyata, Takashi; Sako, Shigeyuki; Kamizuka, Takafumi; Nakamura, Tomohiko; Asano, Kentaro; Okada, Kazushi; Onaka, Takashi; Sakon, Itsuki; Kataza, Hirokazu; Sarugaku, Yuki; Kirino, Okiharu; Nakagawa, Hiroyuki; Okada, Norio; Mitsui, Kenji

    2014-07-01

    We report the restraint deformation and the corrosion protection of gold deposited aluminum mirrors for mid-infrared instruments. To evaluate the deformation of the aluminum mirrors by thermal shrinkage, monitoring measurement of the surface of a mirror has been carried out in the cooling cycles from the room temperature to 100 K. The result showed that the effect of the deformation was reduced to one fourth if the mirror was screwed with spring washers. We have explored an effective way to prevent the mirror from being galvanically corroded. A number of samples have been prepared by changing the coating conditions, such as inserting an insulation layer, making a multi-layer and overcoating water blocking layer, or carrying out precision cleaning before coating. Precision cleaning before the deposition and protecting coat with SiO over the gold layer seemed to be effective in blocking corrosion of the aluminum. The SiO over-coated mirror has survived the cooling test for the mid-infrared use and approximately 1 percent decrease in the reflectance has been detected at 6-25 microns compared to gold deposited mirror without coating.

  19. Concept, modeling, and performance prediction of a low-cost, large deformable mirror.

    PubMed

    Heimsten, Rikard; MacMynowski, Douglas G; Andersen, Torben; Owner-Petersen, Mette

    2012-02-10

    While it is attractive to integrate a deformable mirror (DM) for adaptive optics (AO) into the telescope itself rather than using relay optics within an instrument, the resulting large DM can be expensive, particularly for extremely large telescopes. A low-cost approach for building a large DM is to use voice-coil actuators connected to the back of the DM through suction cups. Use of such inexpensive voice-coil actuators leads to a poorly damped system with many structural modes within the desired bandwidth. Control of the mirror dynamics using electro-mechanical sensors is thus required for integration within an AO system. We introduce a distributed control approach, and we show that the "inner" back sensor control loop does not need to function at low frequencies, leading to significant cost reduction for the sensors. Incorporating realistic models of low-cost actuators and sensors together with an atmospheric seeing model, we demonstrate that the low-cost mirror strategy is feasible within a closed-loop AO system. PMID:22330282

  20. Measurement of a large deformable aspherical mirror using SCOTS (Software Configurable Optical Test System)

    NASA Astrophysics Data System (ADS)

    Huang, Run; Su, Peng; Horne, Todd; Brusa Zappellini, Guido; Burge, Jim H.

    2013-09-01

    The software configurable optical test system (SCOTS) is an efficient metrology technology based on reflection deflectometry that uses only an LCD screen and a camera to measure surface slope. The surface slope is determined by triangulations using the coordinates of the display screen, camera and test mirror. We present our recent SCOTS test results concentrated on high dynamic range measurements of low order aberrations. The varying astigmatism in the 91 cm diameter aspheric deformable secondary mirror for the Large Binocular Telescope (LBT) was measured with SCOTS, requiring no null corrector. The SCOTS system was designed on axis with camera and screen aligned on the optical axis of the test mirror with the help of a 6 inch pellicle beam splitter. The on-axis design gives better control of the astigmatism in the test. The high dynamic range of slope provided a measurement of astigmatism with 0.2 μm rms accuracy in the presence of 231 μm peak-to-valley (PV) aspheric departure. The simplicity of the test allowed the measurements to be performed at multiple elevation angles.

  1. Development of Robust, Light-weight, Agile Deformable Mirrors in Carbon Fiber

    NASA Astrophysics Data System (ADS)

    Hart, M.; Ammons, S. M.; Coughenour, B.; Richardson, L.,; Romeo, R.; Martin, R.

    2012-09-01

    Carbon fiber reinforced polymer (CFRP) has recently been developed to the point that surfaces of high optical quality can be routinely replicated. Building on this advance, we are developing a new generation of deformable mirrors (DMs) for adaptive optics application that extends long-standing expertise at the University of Arizona in large, optically powered DMs for astronomy. Our existing mirrors, up to 90 cm in diameter and with aspheric deformable facesheets, are deployed on a number of large astronomical telescopes. With actuator stroke of up to 50 microns and no hysteresis, they are delivering the best imaging ever seen from an astronomical AO system. Their Zerodur glass ceramic facesheets though are not well suited to non-astronomical applications. In this paper, we describe developmental work to replace the glass components of the DMs with CFRP, an attractive material for optics fabrication because of its high stiffness-to-weight ratio, strength, and very low coefficient of thermal expansion. Surface roughness arising from fiber print-through in the CFRP facesheets is low, < 3 nm PTV across a range of temperature, and the optical figure after correction of static terms by the DM actuators is on the order of 20 nm rms. After initial investment in an optical quality mandrel, replication costs of identical units in CFRP are very low, making the technology ideal for rapid mass production.

  2. Large-aperture deformable mirror correction of tiled-grating wavefront error

    NASA Astrophysics Data System (ADS)

    Kruschwitz, B. E.; Jungquist, R.; Qiao, J.; Abbey, S.; Dean, S. E.; Maywar, D. N.; Moore, M. D.; Waxer, L. J.; Wilson, M. E.

    2006-06-01

    When tiling three gratings, with each individually exhibiting astigmatism and power due to holographic errors and coating stress, the resulting wavefront aberrations contain high-frequency components as well as the fundamental frequency, which is nearly three cycles across the aperture in the tiling direction. A deformable mirror (DM) that was designed to compensate for much slower errors (e.g., those arising from distortion in amplifier disks) is being used to compensate for this tiling-induced error. This investigation studies the effectiveness of compensating only the fundamental frequency of the tiled aberration, and shows that this provides a significant improvement that is adequate for a range of expected aberrations. Limitations of the DM correction technique are also studied.

  3. X-ray metrology and performance of a 45-cm long x-ray deformable mirror.

    PubMed

    Poyneer, Lisa A; Brejnholt, Nicolai F; Hill, Randall; Jackson, Jessie; Hagler, Lisle; Celestre, Richard; Feng, Jun

    2016-05-01

    We describe experiments with a 45-cm long x-ray deformable mirror (XDM) that have been conducted in End Station 2, Beamline 5.3.1 at the Advanced Light Source. A detailed description of the hardware implementation is provided. We explain our one-dimensional Fresnel propagation code that correctly handles grazing incidence and includes a model of the XDM. This code is used to simulate and verify experimental results. Initial long trace profiler metrology of the XDM at 7.5 keV is presented. The ability to measure a large (150-nm amplitude) height change on the XDM is demonstrated. The results agree well with the simulated experiment at an error level of 1 μrad RMS. Direct imaging of the x-ray beam also shows the expected change in intensity profile at the detector. PMID:27250383

  4. X-ray metrology and performance of a 45-cm long x-ray deformable mirror

    DOE PAGESBeta

    Poyneer, Lisa A.; Brejnholt, Nicolai F.; Hill, Randall; Jackson, Jessie; Hagler, Lisle; Celestre, Richard; Feng, Jun

    2016-05-20

    We describe experiments with a 45-cm long x-ray deformable mirror (XDM) that have been conducted in End Station 2, Beamline 5.3.1 at the Advanced Light Source. A detailed description of the hardware implementation is provided. We explain our one-dimensional Fresnel propagation code that correctly handles grazing incidence and includes a model of the XDM. This code is used to simulate and verify experimental results. Initial long trace profiler metrology of the XDM at 7.5 keV is presented. The ability to measure a large (150-nm amplitude) height change on the XDM is demonstrated. The results agree well with the simulated experimentmore » at an error level of 1 μrad RMS. Lastly, direct imaging of the x-ray beam also shows the expected change in intensity profile at the detector.« less

  5. Adaptive optics vision simulator based on 35 element bimorph deformable mirror

    NASA Astrophysics Data System (ADS)

    Zhao, Lina; Dai, Yun; Xiao, Fei; Kang, Jian; Zhao, Haoxin; Bao, Hua; Zhou, Hong; Zhou, Yifeng; Zhang, Yudong

    2014-09-01

    A novel adaptive optics vision simulator (AOVS) is presented and characterized for several design features, including automated measuring and compensating eye's aberrations up to the fifth order, which fully cover aberrations typically found in the human eye, even for the cases of highly aberrated eyes. Especially, it is equipped with 35 elements bimorph deformable mirror with bigger stroke and smaller size, which could help establish near-diffraction-limited ocular optics condition. To investigate the validity of this apparatus, pilot data under different aberration correction pattern from one subjects are collected, and contrast sensitivity function (CSF), an important psychophysical function in vision, is obtained also. Results from living eyes show a practically perfect aberration correction and demonstrate the utility of this system.

  6. Extreme Adaptive Optics Testbed: Performance and Characterization of a 1024 Deformable Mirror

    SciTech Connect

    Evans, J W; Morzinski, K; Severson, S; Poyneer, L; Macintosh, B; Dillon, D; REza, L; Gavel, D; Palmer, D

    2005-10-30

    We have demonstrated that a microelectrical mechanical systems (MEMS) deformable mirror can be flattened to < 1 nm RMS within controllable spatial frequencies over a 9.2-mm aperture making it a viable option for high-contrast adaptive optics systems (also known as Extreme Adaptive Optics). The Extreme Adaptive Optics Testbed at UC Santa Cruz is being used to investigate and develop technologies for high-contrast imaging, especially wavefront control. A phase shifting diffraction interferometer (PSDI) measures wavefront errors with sub-nm precision and accuracy for metrology and wavefront control. 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. An error budget for MEMS closed loop performance will summarize MEMS characterization.

  7. Experience with wavefront sensor and deformable mirror interfaces for wide-field adaptive optics systems

    NASA Astrophysics Data System (ADS)

    Basden, A. G.; Atkinson, D.; Bharmal, N. A.; Bitenc, U.; Brangier, M.; Buey, T.; Butterley, T.; Cano, D.; Chemla, F.; Clark, P.; Cohen, M.; Conan, J.-M.; de Cos, F. J.; Dickson, C.; Dipper, N. A.; Dunlop, C. N.; Feautrier, P.; Fusco, T.; Gach, J. L.; Gendron, E.; Geng, D.; Goodsell, S. J.; Gratadour, D.; Greenaway, A. H.; Guesalaga, A.; Guzman, C. D.; Henry, D.; Holck, D.; Hubert, Z.; Huet, J. M.; Kellerer, A.; Kulcsar, C.; Laporte, P.; Le Roux, B.; Looker, N.; Longmore, A. J.; Marteaud, M.; Martin, O.; Meimon, S.; Morel, C.; Morris, T. J.; Myers, R. M.; Osborn, J.; Perret, D.; Petit, C.; Raynaud, H.; Reeves, A. P.; Rousset, G.; Sanchez Lasheras, F.; Sanchez Rodriguez, M.; Santos, J. D.; Sevin, A.; Sivo, G.; Stadler, E.; Stobie, B.; Talbot, G.; Todd, S.; Vidal, F.; Younger, E. J.

    2016-06-01

    Recent advances in adaptive optics (AO) have led to the implementation of wide field-of-view AO systems. A number of wide-field AO systems are also planned for the forthcoming Extremely Large Telescopes. Such systems have multiple wavefront sensors of different types, and usually multiple deformable mirrors (DMs). Here, we report on our experience integrating cameras and DMs with the real-time control systems of two wide-field AO systems. These are CANARY, which has been operating on-sky since 2010, and DRAGON, which is a laboratory AO real-time demonstrator instrument. We detail the issues and difficulties that arose, along with the solutions we developed. We also provide recommendations for consideration when developing future wide-field AO systems.

  8. Control of the unilluminated deformable mirror actuators in an altitude-conjugated adaptive optics system

    PubMed

    Veran

    2000-07-01

    Off-axis observations made with adaptive optics are severely limited by anisoplanatism errors. However, conjugating the deformable mirror to an optimal altitude can reduce these errors; it is then necessary to control, through extrapolation, actuators that are not measured by the wave-front sensor (unilluminated actuators). In this study various common extrapolation schemes are investigated, and an optimal method that achieves a significantly better performance is proposed. This extrapolation method involves a simple matrix multiplication and will be implemented in ALTAIR, the Gemini North Telescope adaptive optics system located on Mauna Kea, Hawaii. With this optimal method, the relative H-band Strehl reduction due to extrapolation errors is only 5%, 16%, and 30% when the angular distance between the guide source and the science target is 20, 40 and 60 arc sec, respectively. For a site such as Mauna Kea, these errors are largely outweighed by the increase in the size of the isoplanatic field. PMID:10883986

  9. Application of modern-control-design methodologies to a multi-segmented deformable-mirror system. Master's thesis

    SciTech Connect

    Vaughan, E.M.

    1991-05-23

    The multi-segmented deformable mirror system is proposed as an element for a portion of a ballistic missile defense system. The size of the mirror required for this defense function requires that the mirror be developed in segments, and then these segments should be phased together to produce one continuous, large optic. The application of multivariable control system synthesis techniques to provide closed-loop wavefront control of the deformable mirror system is the problem discussed in this thesis. The method of H at infinity control system synthesis using loop-shaping techniques was used to develop a controller that meets a robust performance specification. The number and location of sensors was treated as a design variable, and the structured singular value (mu) was used to determine the performance robustness of the deformable mirror system. Decentralized control issues are also addressed through the use of necessary conditions in an effort to determine a suitable decentralized control structure with performance similar to that of the centralized controller.

  10. Active deformation and engineering analysis of CFRP mirror of various lay-up sequences within quasi-isotropic laminates

    NASA Astrophysics Data System (ADS)

    Zeng, Chunmei; Yu, Xia; Guo, Peiji

    2014-08-01

    A regularization stiffness coefficient method was verified further to optimize lay-up sequences of quasi-isotropic laminates for carbon fiber reinforced polymer (CFRP) composite mirrors. Firstly, the deformation due to gravity of 1G and temperature difference of 20-100°C and the modal were analyzed by finite element method (FEM). Secondly, the influence of angle error of ply stacking on quasi-isotropic of bending stiffness was evaluated. Finally, an active support system of 49 actuators in circular arrangement is designed for a 500mm CFRP mirror, and its goal is to deform the spherical CFRP mirror to a parabolic. Therefore, the response functions of the actuators were gotten, and the surface form errors and stresses were calculated and analyzed. The results show that the CFRP mirrors designed by the method have a better symmetrical bending deformation under gravity and thermal load and a higher fundamental frequency, and the larger n the better symmetry (for π/n quasi-isotropic laminates); the method reduces the sensitivity to misalignment of ply orientation for symmetric bending, and the mirror's maximum von Mises stress and maximum shear stress are less compared to those laminates not optimized in lay-up sequence.

  11. Temperature sensor and display researched based on micro-deformation of beam splitting mirror in holographic system

    NASA Astrophysics Data System (ADS)

    Yang, Delong; Chen, Xiuyan; Gao, Peng; Yu, Ji; Sun, Xue; Wang, Xin

    2015-04-01

    The 45° beam splitting mirror plays a vital role on image quality in the Holographic system, in order to study the influence of environment temperature variation on the 45° beam splitting mirror in the Holographic system, finite element analysis method is used to simulate the anti-three through seven mirror deformation at 27°C, 28°C and 29°C temperature in theory. A new real-time monitoring and displaying photoelectric system for ambient temperature and beam splitting mirror distortion detection is designed to provide real-time temperature change and deformation detection , which is made up of laser speckle interferometer, chip temperature sensor, two-operational amplifier, MCU and LED indicator. And the out-plane displacement value measured in the experiment under the condition of temperature correspondingly are 406nm, 420nm and 427 nm. Finally, the relation equation of temperature and mirror deformation is established by the method of exponential equation fitting, which will provide preliminary theoretical and experimental reference for further research.

  12. Experimental study and analytical model of deformation of magnetostrictive films as applied to mirrors for x-ray space telescopes.

    PubMed

    Wang, Xiaoli; Knapp, Peter; Vaynman, S; Graham, M E; Cao, Jian; Ulmer, M P

    2014-09-20

    The desire for continuously gaining new knowledge in astronomy has pushed the frontier of engineering methods to deliver lighter, thinner, higher quality mirrors at an affordable cost for use in an x-ray observatory. To address these needs, we have been investigating the application of magnetic smart materials (MSMs) deposited as a thin film on mirror substrates. MSMs have some interesting properties that make the application of MSMs to mirror substrates a promising solution for making the next generation of x-ray telescopes. Due to the ability to hold a shape with an impressed permanent magnetic field, MSMs have the potential to be the method used to make light weight, affordable x-ray telescope mirrors. This paper presents the experimental setup for measuring the deformation of the magnetostrictive bimorph specimens under an applied magnetic field, and the analytical and numerical analysis of the deformation. As a first step in the development of tools to predict deflections, we deposited Terfenol-D on the glass substrates. We then made measurements that were compared with the results from the analytical and numerical analysis. The surface profiles of thin-film specimens were measured under an external magnetic field with white light interferometry (WLI). The analytical model provides good predictions of film deformation behavior under various magnetic field strengths. This work establishes a solid foundation for further research to analyze the full three-dimensional deformation behavior of magnetostrictive thin films. PMID:25322105

  13. Image-based calibration of a deformable mirror in wide-field microscopy

    PubMed Central

    Turaga, Diwakar

    2014-01-01

    Optical aberrations limit resolution in biological tissues, and their influence is particularly large for promising techniques like light-sheet microscopy. In principle, image quality might be improved by adaptive optics (AO), in which aberrations are corrected using a deformable mirror (DM). To implement AO in microscopy, one requires a method to measure wavefront aberrations, but the most commonly used methods have limitations for samples lacking point-source emitters. Here we implement an image-based wavefront-sensing technique, a variant of generalized phase-diverse imaging called multi-frame blind deconvolution, and exploit it to calibrate a DM in a light-sheet microscope. We describe two methods of parameterizing the influence of the DM on aberrations: a traditional Zernike expansion requiring 1,040 parameters, and a direct physical model of the DM requiring just 8 or 110 parameters. By randomizing voltages on all actuators, we show that the Zernike expansion successfully predicts wavefronts to an accuracy of approximately 30 nm (rms) even for large aberrations. We thus show that image-based wavefront sensing, which requires no additional optical equipment, allows for a simple but powerful method to calibrate a deformable optical element in a microscope setting. PMID:20390001

  14. Stroke saturation on a MEMS deformable mirror for woofer-tweeter adaptive optics

    NASA Astrophysics Data System (ADS)

    Morzinski, Katie; Macintosh, Bruce; Gavel, Donald; Dillon, Daren

    2009-03-01

    High-contrast imaging of extrasolar planet candidates around a main-sequence star has recently been realized from the ground using current adaptive optics (AO) systems. Advancing such observations will be a task for the Gemini Planet Imager, an upcoming "extreme" AO instrument. High-order "tweeter" and low-order "woofer" deformable mirrors (DMs) will supply a >90%-Strehl correction, a specialized coronagraph will suppress the stellar flux, and any planets can then be imaged in the "dark hole" region. Residual wavefront error scatters light into the DM-controlled dark hole, making planets difficult to image above the noise. It is crucial in this regard that the high-density tweeter, a micro-electrical mechanical systems (MEMS) DM, have sufficient stroke to deform to the shapes required by atmospheric turbulence. Laboratory experiments were conducted to determine the rate and circumstance of saturation, i.e. stroke insufficiency. A 1024-actuator 1.5-um-stroke MEMS device was empirically tested with software Kolmogorov-turbulence screens of r_0=10-15cm. The MEMS when solitary suffered saturation ~4% of the time. Simulating a woofer DM with ~5-10 actuators across a 5-m primary mitigated MEMS saturation occurrence to a fraction of a percent. While no adjacent actuators were saturated at opposing positions, mid-to-high-spatial-frequency stroke did saturate more frequently than expected, implying that correlations through the influence functions are important. Analytical models underpredict the stroke requirements, so empirical studies are important.

  15. Simultaneous correction of large low-order and high-order aberrations with a new deformable mirror technology

    NASA Astrophysics Data System (ADS)

    Rooms, F.; Camet, S.; Curis, J. F.

    2010-02-01

    A new technology of deformable mirror will be presented. Based on magnetic actuators, these deformable mirrors feature record strokes (more than +/- 45μm of astigmatism and focus correction) with an optimized temporal behavior. Furthermore, the development has been made in order to have a large density of actuators within a small clear aperture (typically 52 actuators within a diameter of 9.0mm). We will present the key benefits of this technology for vision science: simultaneous correction of low and high order aberrations, AO-SLO image without artifacts due to the membrane vibration, optimized control, etc. Using recent papers published by Doble, Thibos and Miller, we show the performances that can be achieved by various configurations using statistical approach. The typical distribution of wavefront aberrations (both the low order aberration (LOA) and high order aberration (HOA)) have been computed and the correction applied by the mirror. We compare two configurations of deformable mirrors (52 and 97 actuators) and highlight the influence of the number of actuators on the fitting error, the photon noise error and the effective bandwidth of correction.

  16. Application of a new high-speed magnetic deformable mirror for in-vivo retinal imaging

    NASA Astrophysics Data System (ADS)

    Balderas-Mata, Sandra E.; Jones, Steven M.; Zawadzki, Robert J.; Werner, John S.

    2011-08-01

    Nowadays in ophthalmologic practice several commercial instruments are available to image patient retinas in vivo. Many modern fundus cameras and confocal scanning laser ophthalmoscopes allow acquisition of two dimensional en face images of the retina with both back reflected as well as fluorescent light. Additionally, optical coherence tomography systems allow non-invasive probing of three-dimensional retinal morphology. For all of these instruments the available lateral resolution is limited by optical quality of the human eye used as the imaging objective. To improve lateral resolution and achieve diffraction-limited imaging, adaptive optics (AO) can be implemented with any of these imaging systems to correct both static and dynamic aberrations inherent in human eyes. Most of the wavefront correctors used previously in AO systems have limited dynamic range and an insufficient number of actuators to achieve diffraction-limited correction of most human eyes. Thus, additional corrections were necessary, either by trial lenses or additional deformable mirrors (DMs). The UC Davis AO flood-illuminated fundus camera system described in this paper has been previously used to acquire in vivo images of the photoreceptor mosaic and for psychophysical studies on normal and diseased retinas. These results were acquired using a DM manufactured by Litton ITEK (DM109), which has 109 actuators arranged in a hexagonal array below a continuous front-surface mirror. It has an approximate surface actuator stroke of +/-2μm. Here we present results with a new hi-speed magnetic DM manufactured by ALPAO (DM97, voice coil technology), which has 97 actuators and similar inter-actuator stroke (>3μm, mirror surface) but much higher low-order aberration correction (defocus stroke of at least +/-30μm) than the previous one. In this paper we report results of testing performance of the ALPAO DM for the correction of human eye aberrations. Additionally changes made to our AO flood

  17. Optical zoom lens module using MEMS deformable mirrors for portable device

    NASA Astrophysics Data System (ADS)

    Lu, Jia-Shiun; Su, Guo-Dung J.

    2012-10-01

    The thickness of the smart phones in today's market is usually below than 10 mm, and with the shrinking of the phone volume, the difficulty of its production of the camera lens has been increasing. Therefore, how to give the imaging device more functionality in the smaller space is one of the interesting research topics for today's mobile phone companies. In this paper, we proposed a thin optical zoom system which is combined of micro-electromechanical components and reflective optical architecture. By the adopting of the MEMS deformable mirrors, we can change their radius of curvature to reach the optical zoom in and zoom out. And because we used the all-reflective architecture, so this system has eliminated the considerable chromatic aberrations in the absence of lenses. In our system, the thickness of the zoom system is about 11 mm. The smallest EFL (effective focal length) is 4.61 mm at a diagonal field angle of 52° and f/# of 5.24. The longest EFL of the module is 9.22 mm at a diagonal field angle of 27.4 with f/# of 5.03.°

  18. Characterization of a MEMS deformable mirror by far field intensity evaluation

    NASA Astrophysics Data System (ADS)

    Greiner, Cherry; Finn, Susanna; Choi, Stacey; Doble, Nathan

    2013-03-01

    The performance of an adaptive optics (AO) system is typically measured using the wavefront sensor (WFS). However, another method is to use the point spread function (PSF), which is sensitive to scatter, does not act as a low pass filter and is not dependent on the WFS calibration. We decided to examine the performance of an AO system built for vision science that employed a micromechanical systems (MEMS) based deformable mirror (DM). Specifically, the MEMS DM consists of 489 actuators, resulting in 163 segments each with individual piston/tip/tilt control. Initial evaluation of the DM with a model eye included determining the ability of the DM to generate individual Zernike polynomials and evaluating the far field PSF to measure wavefront correction performance. For individual Zernike polynomial terms, the DM was found to be capable of correcting the aberration magnitudes expected from previously published human population studies.1, 2 Finally, the DM was used in an AO fundus camera to successfully acquire images of cone photoreceptors in a living human eye. This is part of ongoing work which will incorporate the MEMS DM into both an AO scanning laser ophthalmoscope (SLO) and an AO optical coherence tomography (OCT) system where the form of the PSF at the confocal pinhole/optical fiber is important for optimal imaging.

  19. Achieving Sub-Design Level Contrast for Coronagraphs with Deformable Mirrors

    NASA Astrophysics Data System (ADS)

    Eldorado Riggs, A. J.; Groff, T. D.; Carlotti, A.; Kasdin, N. J.

    2013-01-01

    Coronagraphs for space-based detection of earth-like exoplanets are normally designed assuming perfect optics. One or more deformable mirrors (DMs) are then utilized to correct for these aberrations and recover the lost contrast. We demonstrate a new, unified approach in which the coronagraph needs a design contrast only on the order of the errors in the optics. The DMs can then be used to achieve higher contrast by treating small areas of the coronagraph as amplitude errors in the system. This approach eases design and manufacturing constraints on coronagraphs and yields higher throughput designs. Our initial simulations show that a single DM conjugate to a shaped pupil coronagraph can achieve a single-sided dark hole higher in contrast than the shaped pupil is designed for. Future work will focus on simulating double-sided dark holes with two DMs non-conjugate to the pupil plane. This will enable experiments performed in the Princeton High Contrast Imaging (HCIL) Lab with our two Boston Micromachines Corp. kilo-DMs. Symmetric dark holes have already been generated at the HCIL using the Stroke Minimization algorithm and a high contrast shaped pupil in monochromatic and broadband light. Experiments with the unified shaped pupil-DM system will utilize the Kalman filter estimator recently developed in the HCIL for focal plane wavefront correction.

  20. A High-Performance Deformable Mirror with Integrated Driver ASIC for Space Based Active Optics

    NASA Astrophysics Data System (ADS)

    Shelton, Chris

    Direct imaging of exoplanets is key to fully understanding these systems through spectroscopy and astrometry. The primary impediment to direct imaging of exoplanets is the extremely high brightness ratio between the planet and its parent star. Direct imaging requires a technique for contrast suppression, which include coronagraphs, and nulling interferometers. Deformable mirrors (DMs) are essential to both of these techniques. With space missions in mind, Microscale is developing a novel DM with direct integration of DM and its electronic control functions in a single small envelope. The Application Specific Integrated Circuit (ASIC) is key to the shrinking of the electronic control functions to a size compatible with direct integration with the DM. Through a NASA SBIR project, Microscale, with JPL oversight, has successfully demonstrated a unique deformable mirror (DM) driver ASIC prototype based on an ultra-low power switch architecture. Microscale calls this the Switch-Mode ASIC, or SM-ASIC, and has characterized it for a key set of performance parameters, and has tested its operation with a variety of actuator loads, such as piezo stack and unimorph, and over a wide temperature range. These tests show the SM-ASIC's capability of supporting active optics in correcting aberrations of a telescope in space. Microscale has also developed DMs to go with the SM-ASIC driver. The latest DM version produced uses small piezo stack elements in an 8x8 array, bonded to a novel silicon facesheet structure fabricated monolithically into a polished mirror on one side and mechanical linkage posts that connect to the piezoelectric stack actuators on the other. In this Supporting Technology proposal we propose to further develop the ASIC-DM and have assembled a very capable team to do so. It will be led by JPL, which has considerable expertise with DMs used in Adaptive Optics systems, with high-contrast imaging systems for exoplanet missions, and with designing DM driver

  1. A novel deformable mirror with curvature and tip/tilt control based on the spider actuator concept

    NASA Astrophysics Data System (ADS)

    Rodriguez Sanmartin, Daniel; Button, Tim; Meggs, Carl; Michette, Alan; Pfauntsch, Slawka; James, Ady; Willis, Graham; Dunare, Camelia; Stevenson, Tom; Parkes, William

    2012-06-01

    The Smart X-Ray Optics (SXO) project comprises a UK-based consortium developing active/adaptive micro-structured optical arrays (MOAs). MOA devices are designed to focus X-rays using grazing incidence reflection through consecutive aligned arrays of microscopic channels. Adaptability is achieved using a combination of piezoelectric actuators, which bend the edges of the silicon chip, and a spider structure, which forms a series of levers connecting the edges of the chip with the active area at the centre, effectively amplifying the bend radius. The spider actuation concept, in combination with deep silicon etching stopped close to the surface, can also be used to create deformable mirrors where the curvature and tip/tilt angles of the mirror can be controlled. Finite Element Analysis (FEA) modelling, carried out for the optimization of the spider MOA device, indicates that deformable mirrors with curvature varying from flat to 5cm ROC and control over the tip/tilt angles of the mirror of +/-3mrad could be achieved. Test spider structures, manufactured using a Viscous Plastic Processing Process for the PZT piezoelectric actuators and a single wet etch step using <111> planes in a (110) silicon wafer for both the silicon channels and the spider structure, have been bent to a radius of curvature smaller than 5 cm. This paper evaluates the spider MOA's concept as a means to achieve deformable mirrors with controllable ROC and control over the tip/tilt angles. FEA modelling results are compared with obtained characterization data of prototype structures. Finally, manufacturing and integration methods and design characteristics of the device, such its scalability, are also discussed.

  2. Long-Wavelength Beam Steerer Based on a Micro-Electromechanical Mirror

    PubMed Central

    Kos, Anthony B; Gerecht, Eyal

    2013-01-01

    Commercially available mirrors for scanning long-wavelength beams are too large for high-speed imaging. There is a need for a smaller, more agile pointing apparatus to provide images in seconds, not minutes or hours. A fast long-wavelength beam steerer uses a commercial micro-electro-mechanical system (MEMS) mirror controlled by a high-performance digital signal processor (DSP). The DSP allows high-speed raster scanning of the incident radiation, which is focused to a small waist onto the 9mm2, gold-coated, MEMS mirror surface, while simultaneously acquiring an undistorted, high spatial-resolution image of an object. The beam steerer hardware, software and performance are described. The system can also serve as a miniaturized, high-performance long-wavelength beam chopper for lock-in detection. PMID:26401426

  3. Adaptive temporal and wavefront aberration correction for ultrafast lasers with a membrane deformable mirror

    NASA Astrophysics Data System (ADS)

    Sherman, Leah Bruner

    Two adaptive optic systems for correction of either temporal phase error and wavefront errors for ultrafast pulses are demonstrated. These systems consists of a computer controlled micromachined membrane deformable mirror (MMDM) and a genetic learning algorithm (GA). Nonlinear excitation such as two-photon fluorescence or second harmonic generation are used as feedback to the GA to determine the appropriate correction to apply to the mirror. Two MMDMs are used, a 30 x 8 mm, 39 actuator linear MMDM for pulse-shaping applications and a 15 mm diameter, 37 actuator wavefront MMDM. Linear pre-compensation of self-phase modulation (SPM) was experimentally demonstrated utilizing the linear MMDM in a linear pulse-shaper for ultrafast pulses. The nonlinear nature of SPM makes arbitrary polynomial compensation necessary. Pre-compensation of SPM generated in an optical fiber by a 10 fs pulse reduced the pulse from 30fs to 20fs. We demonstrates adaptive correction with the wavefront MMDM by corrected for coma and astigmatism in a reflective multiphoton scanning microscope. An f1, parabola produces a very tight focus with no aberration when it is perfectly aligned. However, when beam scanning is used for two-dimensional imaging the image is severely aberrated. The MMDM and the GA are able to find the best possible wavefront for aberration correction for each scanning position. The horizontal scanning range was increased from 60 mum without the adaptive correction to 170 mum, ≈3 times the uncorrected scanning range, and the vertical scanning range was increased by a comparable amount. This resulted in an increase in scanning area of 9 times. The wavefront MMDM was also used for adaptive correction of spherical aberration from focusing from air, deep into a water-based sample. This depth-based aberration results from an index of refraction mismatch between the sample and the immersion medium of the objective and occurs regardless of beam scanning or sample scanning. By

  4. Universal method for holographic grating recording: multimode deformable mirrors generating Clebsch-Zernike polynomials.

    PubMed

    Lemaître, G R; Duban, M

    2001-02-01

    Recording methods for making aberration-corrected holographic gratings are greatly simplified by use of a plane multimode deformable mirror (MDM) upon one of the two recording beams. It is shown that MDM compensators easily provide the superposition of many interesting active optics modes, which we have named Clebsch-Zernike modes. When we apply only a uniform loading or no loading at all onto the rear side of the MDM clear aperture, the available Clebsch-Zernike modes are made to belong to a subclass of the Zernike modes that includes the three modes of the third-order aberration theory as well as a well-defined part of the Zernike higher-order modes. Such a recording method is considered to be universal, since it does not require the use of a sophisticated optical system such as a compensator. Active optics 12-arm MDM's in the vase form have been designed from the elasticity theory. The design of six-arm MDM's is currently carried out with theoretical results. As an example of the method, the recording of three holographic gratings of the Hubble Space Telescope Cosmic Origins Spectrograph has been investigated. Substantial improvements in image quality have been found by use of a six-arm MDM as recording compensator. The result is that aberrations of much higher order can simultaneously be corrected so that the residual blur images of the spectra occupy areas approximately 10 (direction of dispersion) x 3 (cross dispersion) = 30 times smaller--also in terms of pixel number--than those obtained by our American colleagues. Therefore the active optics recording method appears to provide substantial gains in resolving power and in sensitivity: (i) For all three gratings the spectral resolution would be increased by a factor of 10, and (ii), in addition, for the two higher dispersion gratings, the limiting magnitude on the sky appears to be increased by a magnitude of approximately 1-1.2. PMID:18357020

  5. Dynamic performance of MEMS deformable mirrors for use in an active/adaptive two-photon microscope

    NASA Astrophysics Data System (ADS)

    Zhang, Christian C.; Foster, Warren B.; Downey, Ryan D.; Arrasmith, Christopher L.; Dickensheets, David L.

    2016-03-01

    Active optics can facilitate two-photon microscopic imaging deep in tissue. We are investigating fast focus control mirrors used in concert with an aberration correction mirror to control the axial position of focus and system aberrations dynamically during scanning. With an adaptive training step, sample-induced aberrations may be compensated as well. If sufficiently fast and precise, active optics may be able to compensate under-corrected imaging optics as well as sample aberrations to maintain diffraction-limited performance throughout the field of view. Toward this end we have measured a Boston Micromachines Corporation Multi-DM 140 element deformable mirror, and a Revibro Optics electrostatic 4-zone focus control mirror to characterize dynamic performance. Tests for the Multi-DM included both step response and sinusoidal frequency sweeps of specific Zernike modes. For the step response we measured 10%-90% rise times for the target Zernike amplitude, and wavefront rms error settling times. Frequency sweeps identified the 3dB bandwidth of the mirror when attempting to follow a sinusoidal amplitude trajectory for a specific Zernike mode. For five tested Zernike modes (defocus, spherical aberration, coma, astigmatism and trefoil) we find error settling times for mode amplitudes up to 400nm to be less than 52 us, and 3 dB frequencies range from 6.5 kHz to 10 kHz. The Revibro Optics mirror was tested for step response only, with error settling time of 80 μs for a large 3 um defocus step, and settling time of only 18 μs for a 400nm spherical aberration step. These response speeds are sufficient for intra-scan correction at scan rates typical of two-photon microscopy.

  6. Characterising x-ray mirror deformations with a phase measuring deflectometry system

    NASA Astrophysics Data System (ADS)

    Breunig, E.; Friedrich, P.; Proserpio, L.; Winter, A.

    2014-07-01

    MPE is developing modular x-ray mirrors for the next generation of high-energy astronomy missions. The mirror segments are based on thermally formed (a.k.a. slumped) glass sheets, with a typical thickness of 400µm. One of the major challenges is the alignment and integration of the mirror segments and the associated metrology. The optical performance of the mirror can be significantly compromised by adhesive shrinkage, gravity sag or residual stresses influenced by the properties of the mirror mounting and the integration procedure. In parallel with classic coordinate measurement techniques we utilize a deflectometry based metrology system to characterization shape errors of the mirror surfaces. A typical deflectometry setup uses a TFT display to project a sinusoidal pattern onto a specular test surface (SUT) and a camera that observes the reflected image. This reflected image contains slope information of the SUT in the form of distortions of the original displayed pattern. A phase shifting technique can be used to recover this slope information with only very few exposures and reasonable computational effort. The deflectometry system enables us to characterize bonding interfaces of slumped glass mirrors, as well as influence of temporary mounting points, handling and thermal distortions. It is also well suited to measure transient effects.

  7. Micro-electro-mechanical systems (MEMS) for enzymatic detection

    NASA Astrophysics Data System (ADS)

    Jeetender, Amritsar; Packirisamy, Muthukumaran; Stiharu, Ion G.; Balagopal, Ganesharam

    2004-08-01

    Early enzymatic identification and confirmation is essential for diagnosis and prevention as in the case of Acute Myocardial Infarction (AMI). Biochemical markers continue to be an important clinical tool for the enzymatic detection. The advent of MEMS devices can enable the use of various microstructures for the detection of enzymes. In this study, the concept of MEMS is applied for the detection of enzyme reaction, in which microcantilevers undergo changes in mechanical behavior that can be optically detected when enzyme molecules adsorb on their surface. This paper presents the static behavior of microcantilevers under Horse Radish Peroxide (HRP) enzyme reaction. The reported experimental results provide valuable information that will be useful in the development of MEMS sensors for enzymatic detection. The surface stress produced due to enzyme reactions results in the bending of cantilevers as similar to the influencing of thermal stress in the cantilevers. This paper also reports the influence of thermal gradient on the microcantilevers.

  8. Micro-electro-mechanical systems phosphoric acid fuel cell

    DOEpatents

    Sopchak, David A.; Morse, Jeffrey D.; Upadhye, Ravindra S.; Kotovsky, Jack; Graff, Robert T.

    2010-08-17

    A phosphoric acid fuel cell system comprising a porous electrolyte support, a phosphoric acid electrolyte in the porous electrolyte support, a cathode electrode contacting the phosphoric acid electrolyte, and an anode electrode contacting the phosphoric acid electrolyte.

  9. Micro-electro-mechanical systems phosphoric acid fuel cell

    DOEpatents

    Sopchak, David A.; Morse, Jeffrey D.; Upadhye, Ravindra S.; Kotovsky, Jack; Graff, Robert T.

    2010-12-21

    A phosphoric acid fuel cell system comprising a porous electrolyte support, a phosphoric acid electrolyte in the porous electrolyte support, a cathode electrode contacting the phosphoric acid electrolyte, and an anode electrode contacting the phosphoric acid electrolyte.

  10. A laser-scanning endoscope based on polysilicon micromachined mirrors with enhanced attributes

    NASA Astrophysics Data System (ADS)

    George, Markus; Albrecht, Hansjoerg; Schurr, Marc O.; Papageorgas, Panagiotis G.; Hofmann, Ulrich; Maroulis, Dimitris; Depeursinge, Christian D.; Iakkovidis, Dimitris; Theofanous, Nikiforos; Menciassi, Arianna

    2003-10-01

    A miniaturized laser scanning endoscope is presented which makes use of three lasers to illuminate a sample with a red, a green and a blue wavelength simultaneously. Scattered light from the sample is descanned and chromatically separated into the three channels for detection and postprocessing to compose a color image. The scanning subsystem consists of two micro-electro-mechanical mirrors suitable for mass production. The endoscope head can be assembled fast and at low cost. A resolution of the order of 16 lines per mm is achieved for a working distance common in endoscopy. Considerations of the system design include the operation of the mico mirrors, the filtering of reflected light by using polarization effects and a strategy to cope with color metamery. An expert system based on a neural network was found able to analyze endoscopic images to identify suspicious lesions.

  11. Large aperture deformable mirror with a transferred single-crystal silicon membrane actuated using large-stroke PZT Unimorph Actuators

    NASA Technical Reports Server (NTRS)

    Hishinumat, Yoshikazu; Yang, Eui - Hyeok (EH)

    2005-01-01

    We have demonstrated a large aperture (50 mm x 50 mm) continuous membrane deformable mirror (DM) with a large-stroke piezoelectric unimorph actuator array. The DM consists of a continuous, large aperture, silicon membrane 'transferred' in its entirety onto a 20 x 20 piezoelectric unimorph actuator array. A PZT unimorph actuator, 2.5 mm in diameter with optimized PZT/Si thickness and design showed a deflection of 5.7 [m at 20V. An assembled DM showed an operating frequency bandwidth of 30 kHz and influence function of approximately 30%.

  12. Stress polishing of thin shells for adaptive secondary mirrors. Application to the Very Large Telescope deformable secondary

    NASA Astrophysics Data System (ADS)

    Hugot, E.; Ferrari, M.; Riccardi, A.; Xompero, M.; Lemaître, G. R.; Arsenault, R.; Hubin, N.

    2011-03-01

    Context. Adaptive secondary mirrors (ASM) are, or will be, key components on all modern telescopes, providing improved seeing conditions or diffraction limited images, thanks to the high-order atmospheric turbulence correction obtained by controlling the shape of a thin mirror. Their development is a key milestone towards future extremely large telescopes (ELT) where this technology is mandatory for successful observations. Aims: The key point of actual adaptive secondaries technology is the thin glass mirror that acts as a deformable membrane, often aspheric. On 6 m - 8 m class telescopes, these are typically 1 m-class with a 2 mm thickness. The optical quality of this shell must be sufficiently good not to degrade the correction, meaning that high spatial frequency errors must be avoided. The innovative method presented here aims at generating aspherical shapes by elastic bending to reach high optical qualities. Methods: This method is called stress polishing and allows generating aspherical optics of a large amplitude with a simple spherical polishing with a full sized lap applied on a warped blank. The main advantage of this technique is the smooth optical quality obtained, free of high spatial frequency ripples as they are classically caused by subaperture toolmarks. After describing the manufacturing process we developed, our analytical calculations lead to a preliminary definition of the geometry of the blank, which allows a precise bending of the substrate. The finite element analysis (FEA) can be performed to refine this geometry by using an iterative method with a criterion based on the power spectral density of the displacement map of the optical surface. Results: Considering the specific case of the Very Large Telescope (VLT) deformable secondary mirror (DSM), extensive FEA were performed for the optimisation of the geometry. Results are showing that the warping will not introduce surface errors higher than 0.3 nm rms on the minimal spatial scale

  13. Robust Wave-front Correction in a Small Scale Adaptive Optics System Using a Membrane Deformable Mirror

    NASA Astrophysics Data System (ADS)

    Choi, Y.; Park, S.; Baik, S.; Jung, J.; Lee, S.; Yoo, J.

    A small scale laboratory adaptive optics system using a Shack-Hartmann wave-front sensor (WFS) and a membrane deformable mirror (DM) has been built for robust image acquisition. In this study, an adaptive limited control technique is adopted to maintain the long-term correction stability of an adaptive optics system. To prevent the waste of dynamic correction range for correcting small residual wave-front distortions which are inefficient to correct, the built system tries to limit wave-front correction when a similar small difference wave-front pattern is repeatedly generated. Also, the effect of mechanical distortion in an adaptive optics system is studied and a pre-recognition method for the distortion is devised to prevent low-performance system operation. A confirmation process for a balanced work assignment among deformable mirror (DM) actuators is adopted for the pre-recognition. The corrected experimental results obtained by using a built small scale adaptive optics system are described in this paper.

  14. Design and fabrication of a high precision x-ray deformable mirror

    NASA Astrophysics Data System (ADS)

    Brooks, Audrey; Wirth, Allan; Lintz, Eric; Cavaco, Jeffrey

    2014-09-01

    AOA-Xinetics has been developing techniques for shaping grazing incidence optics with surface-normal and surface-parallel electrostrictive Lead magnesium niobate (PMN) actuators bonded to mirror substrates for several years. These actuators are highly reliable; exhibit little to no hysteresis, aging or creep; and can be closely spaced to correct low and mid-spatial frequency errors in a compact package. In this paper we discuss the design and fabrication of a 45cm grazing incidence mirror fitted with 45 PMN actuators and integral strain gauges and temperature sensors that allow sub-nanometer control of the surface figure.

  15. Micromachined mirrors

    NASA Astrophysics Data System (ADS)

    Conant, Robert Alan

    This dissertation discusses the fundamental limits of scanning mirror design, focusing on the limitations due to the interaction between mechanical properties (mirror flatness and dynamic deformation), and optical properties (beam divergence and optical resolution). The performance criteria for both resonant-scanning mirrors and steady-state, beam-positioning mirrors are related to the mirror geometries, desired optical resolution, material properties, and mechanical resonant frequencies. The optical resolution of the scanning mirror is linearly dependent on the mirror length, so longer mirrors should provide higher-resolution scanners. However, when undergoing an angular acceleration mirrors exhibit dynamic deformation, which is shown to be proportional to the fifth power of the length. Two different implementations of MEMS scanning mirrors are presented: polysilicon surface-micromachined mirrors and a new design we call the Staggered Torsional Electrostatic Combdrive (STEC) micromirror. The surface-micromachined mirrors are shown to be capable of reliable operation, but they have significant performance limitations caused by the limited thickness obtainable with the LPCVD-polysilicon structures. Calculations show that surface-micromachined mirrors of thickness 1.5 mum and diameter 550 mum are only capable of scanning +/-10 degrees at 251 Hz while retaining diffraction-limited optical performance. The STEC micromirrors, designed to overcome the limitations of the surface-micromachined mirrors, are capable of much higher-speed scanning (up to 61 kHz) without performance-limiting dynamic deformation of the mirror surface. The STEC micromirror fabrication process is extended to create Tensile Optical Surface (TOS) micromirrors---mirrors with thick silicon rib support structures and thin membranes that provide the reflective surface. An application of scanning mirrors is presented: a raster-scanning video display. This demonstration uses two surface

  16. Deformable mirror based on piezoelectric actuators for the adaptive system of the Iskra-6 facility

    SciTech Connect

    Bokalo, S Yu; Zhupanov, V G; Lyakhov, D M; Mizin, P P; Smekalin, V P; Shanin, Oleg I; Shchipalkin, V I; Garanin, Sergey G; Grigorovich, S V; Koltygin, M O; Kulikov, S M; Manachinckii, A N; Ogorodnikov, A V; Smyshlyaev, S P; Sukharev, Stanislav A

    2007-08-31

    The main problem in developing high-power pulsed laser facilities (NIF, LMJ, and Iskra-6) is to provide the required quality of their output radiation. For this purpose, adaptive optical systems (AOSs) are used in all these facilities. The present research is devoted to determining the characteristics and working out the most troublesome elements of the AOS - the wavefront sensor and wide-aperture adaptive mirror for the Iskra-6 facility. (selected papers reported at the conference 'laser optics 2006')

  17. Design of a Compact, Bimorph Deformable Mirror-Based Adaptive Optics Scanning Laser Ophthalmoscope.

    PubMed

    He, Yi; Deng, Guohua; Wei, Ling; Li, Xiqi; Yang, Jinsheng; Shi, Guohua; Zhang, Yudong

    2016-01-01

    We have designed, constructed and tested an adaptive optics scanning laser ophthalmoscope (AOSLO) using a bimorph mirror. The simulated AOSLO system achieves diffraction-limited criterion through all the raster scanning fields (6.4 mm pupil, 3° × 3° on pupil). The bimorph mirror-based AOSLO corrected ocular aberrations in model eyes to less than 0.1 μm RMS wavefront error with a closed-loop bandwidth of a few Hz. Facilitated with a bimorph mirror at a stroke of ±15 μm with 35 elements and an aperture of 20 mm, the new AOSLO system has a size only half that of the first-generation AOSLO system. The significant increase in stroke allows for large ocular aberrations such as defocus in the range of ±600° and astigmatism in the range of ±200°, thereby fully exploiting the AO correcting capabilities for diseased human eyes in the future. PMID:27526166

  18. Demonstration of a robust curved carbon fiber reinforced polymer deformable mirror with low surface error

    NASA Astrophysics Data System (ADS)

    Coughenour, Blake; Ammons, S. Mark; Hart, Michael; Romeo, Robert; Martin, Robert; Rademacher, Matt; Bailey, Hop

    2010-07-01

    Carbon fiber reinforced polymer (CFRP) composites provide several advantages as a substrate for thin-shell adaptive secondary mirrors, including high stiffness-to-weight ratio and low coefficient of thermal expansion (CTE). We have addressed some of these concerns using a prototype CFRP mirror under actuation. Using 4D and Newton interferometry, we present measurements of surface quality at a range of temperatures. Under actuator relaxation at room temperature, its surface error is low (92 nm RMS) and dominated by edge curvature. This error is reduced further under best actuator correction to 43 nm RMS, placing it into consideration for use in near-IR astronomy. The low surface error internal to the outer ring of actuators - 17 nm RMS at 60°F and 33 nm RMS at 20°F - suggests that larger mirrors will have a similar figure quality under actuator correction on ground-based AO systems. Furthermore, the actuator forces required to correct the figure are small compared to the dynamic range of voice coil actuators (~0.1 N). In addition, surface roughness is characterized to address the effects of high spatial frequency errors.

  19. Pair-Wise, Deformable Mirror, Image Plane-Based Diversity Electric Field Estimation for High Contrast Coronagraphy

    NASA Technical Reports Server (NTRS)

    Give'on, Amir; Kern, Brian D.; Shaklan, Stuart

    2011-01-01

    In this paper we describe the complex electric field reconstruction from image plane intensity measurements for high contrast coronagraphic imaging. A deformable mirror (DM) surface is modied with pairs of complementary shapes to create diversity in the image plane of the science camera where the intensity of the light is measured. Along with the Electric Field Conjugation correction algorithm, this estimation method has been used in various high contrast imaging testbeds to achieve the best contrasts to date both in narrow and in broad band light. We present the basic methodology of estimation in easy to follow list of steps, present results from HCIT and raise several open quations we are confronted with using this method.

  20. Monte Carlo simulation of ELT-scale multi-object adaptive optics deformable mirror requirements and tolerances

    NASA Astrophysics Data System (ADS)

    Basden, A. G.; Bharmal, N. A.; Myers, R. M.; Morris, S. L.; Morris, T. J.

    2013-10-01

    Multi-object adaptive optics (MOAO) has been demonstrated by the CANARY instrument on the William Herschel Telescope. However, for proposed MOAO systems on the next-generation extremely large telescopes (ELTs), such as ELT Adaptive optics for GaLaxy Evolution (EAGLE), many challenges remain. Here we investigate requirements that MOAO operation places on deformable mirrors (DMs) using a full end-to-end Monte Carlo adaptive optics (AO) simulation code. By taking into consideration a prior global ground-layer (GL) correction, we show that actuator density for the MOAO DMs can be reduced with little performance loss. We note that this reduction is only possible with the addition of a GL DM, whose order is greater than or equal to that of the original MOAO mirrors. The addition of a GL DM of lesser order does not affect system performance (if tip/tilt star sharpening is ignored). We also quantify the maximum mechanical DM stroke requirements (3.5 μm desired) and provide tolerances for the DM alignment accuracy, both lateral (to within an eighth of a sub-aperture) and rotational (to within 0.2°). By presenting results over a range of laser guide star asterism diameters, we ensure that these results are equally applicable for laser tomographic AO systems. We provide the opportunity for significant cost savings to be made in the implementation of MOAO systems, resulting from the lower requirement for DM actuator density.

  1. Illustration of the use of multimode deformable plane mirrors to record high-resolution concave gratings: results for the Cosmic Origins Spectrograph gratings of the Hubble Space Telescope.

    PubMed

    Duban, M; Dohlen, K; Lemaitre, G R

    1998-11-01

    To illustrate the efficiency of using a deformable plane mirror to record holographic gratings, we have computed the three gratings for the Cosmic Origins Spectrograph. Their working conditions are severe, since they have to correct the residual spherical aberration of the Hubble Space Telescope. Nevertheless, all images obtained are largely diffraction limited with regard to the resolution. PMID:18301548

  2. Nearly diffraction-limited X-ray focusing with variable-numerical-aperture focusing optical system based on four deformable mirrors

    PubMed Central

    Matsuyama, Satoshi; Nakamori, Hiroki; Goto, Takumi; Kimura, Takashi; Khakurel, Krishna P.; Kohmura, Yoshiki; Sano, Yasuhisa; Yabashi, Makina; Ishikawa, Tetsuya; Nishino, Yoshinori; Yamauchi, Kazuto

    2016-01-01

    Unlike the electrostatic and electromagnetic lenses used in electron microscopy, most X-ray focusing optical systems have fixed optical parameters with constant numerical apertures (NAs). This lack of adaptability has significantly limited application targets. In the research described herein, we developed a variable-NA X-ray focusing system based on four deformable mirrors, two sets of Kirkpatrick–Baez-type focusing mirrors, in order to control the focusing size while keeping the position of the focus unchanged. We applied a mirror deformation procedure using optical/X-ray metrology for offline/online adjustments. We performed a focusing test at a SPring-8 beamline and confirmed that the beam size varied from 108 nm to 560 nm (165 nm to 1434 nm) in the horizontal (vertical) direction by controlling the NA while maintaining diffraction-limited conditions. PMID:27097853

  3. Nearly diffraction-limited X-ray focusing with variable-numerical-aperture focusing optical system based on four deformable mirrors

    NASA Astrophysics Data System (ADS)

    Matsuyama, Satoshi; Nakamori, Hiroki; Goto, Takumi; Kimura, Takashi; Khakurel, Krishna P.; Kohmura, Yoshiki; Sano, Yasuhisa; Yabashi, Makina; Ishikawa, Tetsuya; Nishino, Yoshinori; Yamauchi, Kazuto

    2016-04-01

    Unlike the electrostatic and electromagnetic lenses used in electron microscopy, most X-ray focusing optical systems have fixed optical parameters with constant numerical apertures (NAs). This lack of adaptability has significantly limited application targets. In the research described herein, we developed a variable-NA X-ray focusing system based on four deformable mirrors, two sets of Kirkpatrick–Baez-type focusing mirrors, in order to control the focusing size while keeping the position of the focus unchanged. We applied a mirror deformation procedure using optical/X-ray metrology for offline/online adjustments. We performed a focusing test at a SPring-8 beamline and confirmed that the beam size varied from 108 nm to 560 nm (165 nm to 1434 nm) in the horizontal (vertical) direction by controlling the NA while maintaining diffraction-limited conditions.

  4. Nearly diffraction-limited X-ray focusing with variable-numerical-aperture focusing optical system based on four deformable mirrors.

    PubMed

    Matsuyama, Satoshi; Nakamori, Hiroki; Goto, Takumi; Kimura, Takashi; Khakurel, Krishna P; Kohmura, Yoshiki; Sano, Yasuhisa; Yabashi, Makina; Ishikawa, Tetsuya; Nishino, Yoshinori; Yamauchi, Kazuto

    2016-01-01

    Unlike the electrostatic and electromagnetic lenses used in electron microscopy, most X-ray focusing optical systems have fixed optical parameters with constant numerical apertures (NAs). This lack of adaptability has significantly limited application targets. In the research described herein, we developed a variable-NA X-ray focusing system based on four deformable mirrors, two sets of Kirkpatrick-Baez-type focusing mirrors, in order to control the focusing size while keeping the position of the focus unchanged. We applied a mirror deformation procedure using optical/X-ray metrology for offline/online adjustments. We performed a focusing test at a SPring-8 beamline and confirmed that the beam size varied from 108 nm to 560 nm (165 nm to 1434 nm) in the horizontal (vertical) direction by controlling the NA while maintaining diffraction-limited conditions. PMID:27097853

  5. Development of an ELT XAO testbed using a Mach-Zehnder wavefront sensor: calibration of the deformable mirror

    NASA Astrophysics Data System (ADS)

    Delacroix, Christian; Langlois, Maud P.; Loupias, Magali; Thiébaut, Eric; Adjali, Louisa; Leger, Jonathan; Tallon, Michel

    2015-09-01

    Extreme adaptive optics (XAO) encounters severe difficulties to cope with the high speed (<1kHz), high accuracy and high order requirements for future extremely large telescopes. An innovative high order adaptive optics system using a self-referenced Mach-Zehnder wavefront sensor (MZWFS) allows counteracting these limitations. This sensor estimates very accurately the wavefront phase at small spatial scale by measuring intensity differences between two outputs, with a λ/4 path length difference between its two legs, but is limited in dynamic range due to phase ambiguity. During the past few years, such an XAO system has been studied by our team in the framework of 8-meter class telescopes. In this work, we report on our latest results with the XAO testbed recently installed in our lab, and dedicated to high contrast imaging with 30m-class telescopes (such as the E-ELT or the TMT). After reminding the principle of a MZWFS and describing the optical layout of our experiment, we will show the results of the assessment of the woofer-tweeter phase correctors, i.e., a Boston Micromachine continuous membrane deformable mirror (DM) and a Boulder Nonlinear Systems liquid crystal spatial light modulator (SLM). In particular, we will detail the calibration of the DM using Zygo interferometer metrology. Our method consists in the precise measurement of the membrane deformation while applying a constant deformation to 9 out of 140 actuators at the same time. By varying the poke voltage across the DM operating range, we propose a simple but efficient way of modeling the DM influence function using a Gaussian model. Finally, we show the DM flattening on the MZWFS allowing to compensate for low order aberrations. This work is carried out in synergy with the validation of fast iterative wavefront reconstruction algorithms, and the optimal treatment of phase ambiguities in order to mitigate the dynamical range limitation of such an MZWFS.

  6. Technological progress of a ferrofluid deformable mirror with tunable nominal optical power for high-contrast imaging

    NASA Astrophysics Data System (ADS)

    Lemmer, Aaron J.; Groff, Tyler D.; Kasdin, N. Jeremy; Echeverri, Daniel; Cleff, Isabel R.

    2015-09-01

    The success of a space-borne direct-imaging mission pursuing earth-sized exoplanets in the habitable zone hinges on the ability to achieve high contrast over a maximum field of view. Coronagraphic instruments designed to address this challenge suffer from optical aberrations and rely on focal-plane wavefront control to suppress the resulting speckles and widen the search area. Even small-featured quasi-static speckles--which may obscure or be confused with a planet--must be suppressed to the order of 10-10 over the search region, placing extreme demands on the deformable mirrors (DMs) used to implement the closed-loop control, both in wavefront requirements and actuation resolution. The ideal DM for focal-plane wavefront control has high surface quality and is capable of high-precision, low-stroke actuation. Conventional mirror technologies such as MEMS DMs, with heritage in ground-based adaptive optics instruments that correct for dynamic atmosphere-induced aberrations, are nominally at and provide high-stroke, high-resolution control but at a cost of precision and surface quality. We present a new technology currently under development at Princeton, which features a ferrofluid-supported optical surface with local magnetic actuation. The actuation is transferred to the optical surface through a liquid medium which continuously supports it, decoupling the nominal surface profile from the actuator configuration and eliminating quilting. Additionally, the device carries tunable nominal optical power via regulation of the ferrofluid pressure, permitting a degree of high-fidelity low-order wavefront control impossible with current instrumentation. We report on the continuing technological growth of the prototype device, including progress with actuation, metrology, and modeling of the DM response.

  7. Enantiomeric switching of chiral metamaterial for terahertz polarization modulation employing vertically deformable MEMS spirals

    NASA Astrophysics Data System (ADS)

    Kan, Tetsuo; Isozaki, Akihiro; Kanda, Natsuki; Nemoto, Natsuki; Konishi, Kuniaki; Takahashi, Hidetoshi; Kuwata-Gonokami, Makoto; Matsumoto, Kiyoshi; Shimoyama, Isao

    2015-10-01

    Active modulation of the polarization states of terahertz light is indispensable for polarization-sensitive spectroscopy, having important applications such as non-contact Hall measurements, vibrational circular dichroism measurements and anisotropy imaging. In the terahertz region, the lack of a polarization modulator similar to a photoelastic modulator in the visible range hampers expansion of such spectroscopy. A terahertz chiral metamaterial has a huge optical activity unavailable in nature; nevertheless, its modulation is still challenging. Here we demonstrate a handedness-switchable chiral metamaterial for polarization modulation employing vertically deformable Micro Electro Mechanical Systems. Vertical deformation of a planar spiral by a pneumatic force creates a three-dimensional spiral. Enantiomeric switching is realized by selecting the deformation direction, where the polarity of the optical activity is altered while maintaining the spectral shape. A polarization rotation as high as 28° is experimentally observed, thus providing a practical and compact polarization modulator for the terahertz range.

  8. Enantiomeric switching of chiral metamaterial for terahertz polarization modulation employing vertically deformable MEMS spirals

    PubMed Central

    Kan, Tetsuo; Isozaki, Akihiro; Kanda, Natsuki; Nemoto, Natsuki; Konishi, Kuniaki; Takahashi, Hidetoshi; Kuwata-Gonokami, Makoto; Matsumoto, Kiyoshi; Shimoyama, Isao

    2015-01-01

    Active modulation of the polarization states of terahertz light is indispensable for polarization-sensitive spectroscopy, having important applications such as non-contact Hall measurements, vibrational circular dichroism measurements and anisotropy imaging. In the terahertz region, the lack of a polarization modulator similar to a photoelastic modulator in the visible range hampers expansion of such spectroscopy. A terahertz chiral metamaterial has a huge optical activity unavailable in nature; nevertheless, its modulation is still challenging. Here we demonstrate a handedness-switchable chiral metamaterial for polarization modulation employing vertically deformable Micro Electro Mechanical Systems. Vertical deformation of a planar spiral by a pneumatic force creates a three-dimensional spiral. Enantiomeric switching is realized by selecting the deformation direction, where the polarity of the optical activity is altered while maintaining the spectral shape. A polarization rotation as high as 28° is experimentally observed, thus providing a practical and compact polarization modulator for the terahertz range. PMID:26423346

  9. Adaptive non-collinear autocorrelation of few-cycle pulses with an angular tunable bi-mirror

    NASA Astrophysics Data System (ADS)

    Treffer, A.; Brunne, J.; Bock, M.; König, S.; Wallrabe, U.; Grunwald, R.

    2016-02-01

    Adaptive autocorrelation with an angular tunable micro-electro-mechanical system is reported. A piezo-actuated Fresnel bi-mirror structure was applied to measure the second order autocorrelation of near-infrared few-cycle laser pulses in a non-collinear setup at tunable superposition angles. Because of enabling measurements with variable scaling and minimizing the influence of distortions by adaptive self-reconstruction, the approach extends the capability of autocorrelators. Flexible scaling and robustness against localized amplitude obscurations are demonstrated. The adaptive reconstruction of temporal frequency information by the Fourier analysis of autocorrelation data is shown. Experimental results and numerical simulations of the beam propagation and interference are compared for variable angles.

  10. Deformation analysis of MEMS structures by modified digital moiré methods

    NASA Astrophysics Data System (ADS)

    Liu, Zhanwei; Lou, Xinhao; Gao, Jianxin

    2010-11-01

    Quantitative deformation analysis of micro-fabricated electromechanical systems is of importance for the design and functional control of microsystems. In this paper, two modified digital moiré processing methods, Gaussian blurring algorithm combined with digital phase shifting and geometrical phase analysis (GPA) technique based on digital moiré method, are developed to quantitatively analyse the deformation behaviour of micro-electro-mechanical system (MEMS) structures. Measuring principles and experimental procedures of the two methods are described in detail. A digital moiré fringe pattern is generated by superimposing a specimen grating etched directly on a microstructure surface with a digital reference grating (DRG). Most of the grating noise is removed from the digital moiré fringes, which enables the phase distribution of the moiré fringes to be obtained directly. Strain measurement result of a MEMS structure demonstrates the feasibility of the two methods.

  11. Design of the Apache-Point Observatory 3.5-METER Telescope - Part Two - Deformation Analysis of the Primary Mirror

    NASA Astrophysics Data System (ADS)

    Siegmund, W. A.; Mannery, E. J.; Radochia, J.; Gillett, P. E.

    1986-01-01

    The authors have calculated the deflection of the surface of a 3.5 meter diameter borosilicate mirror using the finite element method. The mirror is a 0.46 m thick honeycomb structure with 25 mm thick face plates and 13 mm ribs. The cell spacing is 0.192 m and is regular except near the inner and outer perimeters. Axial support for the mirror will be provided by 48 air pistons. The effects of thickness variations in fabrication of the mirror are presented and are small for the magnitudes of the variations expected. Several thermal load cases are described.

  12. TOPICAL REVIEW Elasto-capillarity: deforming an elastic structure with a liquid droplet

    NASA Astrophysics Data System (ADS)

    Roman, B.; Bico, J.

    2010-12-01

    Although negligible at macroscopic scales, capillary forces become dominant as the sub-millimetric scales of micro-electro-mechanical systems (MEMS) are considered. We review various situations, not limited to micro-technologies, where capillary forces are able to deform elastic structures. In particular, we define the different length scales that are relevant for 'elasto-capillary' problems. We focus on the case of slender structures (lamellae, rods and sheets) and describe the size of a bundle of wet hair, the condition for a flexible rod to pierce a liquid interface or the fate of a liquid droplet deposited on a flexible thin sheet. These results can be generalized to similar situations involving adhesion or fracture energy, which widens the scope of possible applications from biological systems, to stiction issues in micro-fabrication processes, the manufacturing of 3D microstructures or the formation of blisters in thin film coatings.

  13. The actuator design and the experimental tests of a new technology large deformable mirror for visible wavelengths adaptive optics

    NASA Astrophysics Data System (ADS)

    Del Vecchio, Ciro; Agapito, Guido; Arcidiacono, Carmelo; Carbonaro, Luca; Marignetti, Fabrizio; De Santis, Enzo; Biliotti, Valdemaro; Riccardi, Armando

    2012-07-01

    Recently, Adaptive Secondary Mirrors showed excellent on-sky results in the Near Infrared wavelengths. They currently provide 30mm inter-actuator spacing and about 1 kHz bandwidth. Pushing these devices to be operated at visible wavelengths is a challenging task. Compared to the current systems, working in the infrared, the more demanding requirements are the higher spatial resolution and the greater correction bandwidth. In fact, the turbulence scale is shorter and the parameter variation is faster. Typically, the former is not larger than 25 mm (projected on the secondary mirror) and the latter is 2 kHz, therefore the actuator has to be more slender and faster than the current ones. With a soft magnetic composite core, a dual-stator and a single-mover, VRALA, the actuator discussed in this paper, attains unprecedented performances with a negligible thermal impact. Pre-shaping the current required to deliver a given stroke greatly simplifies the control system, whose output supplies the current generator. As the inductance depends on the mover position, the electronics of this generator, provided with an inductance measure circuit, works also as a displacement sensor, supplying the control system with an accurate feed-back signal. A preliminary prototype, built according to the several FEA thermo-magnetic analyses, has undergone some preliminary laboratory tests. The results of these checks, matching the design results in terms of power and force, show that the the magnetic design addresses the severe specifications.

  14. Controllable Mirror Devices

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A deformable Mirror Device (DMD) is a type of spatial light modulator in which mirrors fabricated monolithically on a silicon chip are deformed, or tilted, under electronic control to change the direction of light that falls upon the mirror. NASA and Texas Instruments (TI) have worked to develop this technology, which has subsequently been commercialized by TI. Initial application is the DMD 2000 Travel Information Printer for high speed, high volume printing of airline tickets and boarding passes. Other possible applications range from real-time object tracking to advanced industrial machine vision systems.

  15. Full-system laboratory testing of the F/15 deformable secondary mirror for the new MMT adaptive optics system

    NASA Astrophysics Data System (ADS)

    Mcguire, Patrick C.; Lloyd-Hart, Michael; Angel, J. Roger P.; Angeli, George Z.; Johnson, Robert L.; Fitz-Patrick, Bruce C.; Davison, Warren B.; Sarlot, Roland J.; Bresloff, Cynthia J.; Hughes, John M.; Miller, Stephen M.; Schaller, Skip; Wildi, Francois P.; Kenworthy, Matthew A.; Cordova, Richard M.; Rademacher, Matthew J.; Rascon, Mario H.; Burge, James H.; Stamper, Brian L.; Zhao, Chunyu; Salinari, Piero; del Vecchio, Ciro; Riccardi, Armando; Brusa, Guido; Biasi, Roberto; Andrighettoni, Mario; Gallieni, Daniele; Franchini, Claudio; Sandler, David G.; Barrett, Todd K.

    1999-09-01

    We will present a system to perform closed-loop optical tests of the 64 cm diameter, 336 actuator adaptive secondary made at the Steward Observatory Mirror Laboratory. Testing will include Shack-Hartmann wavefront sensing and modal correction of static and dynamic aberrated wavefronts. The test optical system is designed so that experiments can be made with both the focal plane instrument and secondary installed in their normal configuration at the MMT, or with the same 9 m spacing in a laboratory test tower. The convex secondary will be illuminated at normal incidence through two 70 cm diameter lenses mounted just below. The artificial, aberrated star is projected from near the wavefront sensor in the Cassegrain focus assembly. Computer generated holograms correct for spherical aberration in the really optics at the test wavelengths of 0.594 and 1.5 micrometers . Atmospheric turbulence is reproduced by two spinning transmission plates imprinted with Kolmogorov turbulence. The Shimmulator will give us the opportunity to test fully the adaptive optics system before installation at the new MMT, hence saving much precious telescope time.

  16. Advanced Adaptive Optics Technology Development

    SciTech Connect

    Olivier, S

    2001-09-18

    The NSF Center for Adaptive Optics (CfAO) is supporting research on advanced adaptive optics technologies. CfAO research activities include development and characterization of micro-electro-mechanical systems (MEMS) deformable mirror (DM) technology, as well as development and characterization of high-resolution adaptive optics systems using liquid crystal (LC) spatial light modulator (SLM) technology. This paper presents an overview of the CfAO advanced adaptive optics technology development activities including current status and future plans.

  17. Micro-electro-mechanical system-based digitally controlled optical beam profiler

    NASA Astrophysics Data System (ADS)

    Sumriddetchkajorn, Sarun; Riza, Nabeel A.

    2002-06-01

    An optical beam profiler is introduced that uses a two-dimensional (2-D) small-tilt micromirror device. Its key features include fast speed, digital control, low polarization sensitivity, and wavelength independence. The use of this 2-D multipixel device opens up the important possibility of realizing several beam profile measurement concepts, such as a moving knife edge, a scanning slit, a moving pinhole, a variable aperture, and a 2-D photodiode array. The experimental proof of the optical beam profiler concept using a 2-D digital micromirror device to simulate the 2-D moving knife edge indicates a small measurement error of 0.19% compared with the expected number based on a Gaussian beam-propagation analysis. Other 2-D pixel arrays such as a liquid-crystal-based 90deg polarization rotator sandwiched between crossed polarizers can also be exploited for the optical beam whose polarization direction is known.

  18. Micro-electro-mechanical flapping wing technology for micro air vehicles

    NASA Astrophysics Data System (ADS)

    Hall, Asha J.; Riddick, Jaret C.

    2012-04-01

    Army combat operations have placed a high premium on reconnaissance missions for Unmanned Aerial Vehicles (UAVs) and Micro Air Vehicles (MAVs) (less than 15 cm in dimension and less than 20 g in mass). One approach for accomplishing this mission is to develop a biologically inspired flapping wing insect that can maneuver into confined areas and possess hovering capabilities. Analysis of insect flight indicates that in addition to the bending excitation (flapping), simultaneous excitation of the twisting degree-of-freedom (pitching) is required to manipulate the control surface adequately. Traditionally, bimorph piezoelectric PZT (Pb(Zr0.55Ti0.45)O3) actuators have been used in many applications to excite the bending degree-of-freedom. In laminated or layered structures, bend-twist coupling is governed by the existence of at least one anisotropic layer not aligned with the primary plate axes. By adding a layer of off-axis PZT segments to a PZT bimorph actuator, thereby producing a layered structure to be referred to as a functionally- modified bimorph, bend-twist coupling may be introduced to the flexural response of the layered PZT. Furthermore, by selectively charging off-axis layers in specific combinations with the bimorph, the response of the functionally-modified bimorph may be tailored yielding a biaxial actuator to actively control the flapping wing response. The present study presents an experimental investigation of both traditional bimorph and functionally-modified PZT bimorph designs intended for active bend-twist actuation of cm-scale flapping wing devices.

  19. Applications of ferrofluids in Micro Electro Mechanical Systems (MEMS) and micropumps

    NASA Astrophysics Data System (ADS)

    Jain, V. K.; Pant, R. P.; Vinod Kumar, .

    2008-12-01

    The micro-pump is one of the most promising micro-flow devices. At micro-level electronically controlled pumping of any fluid by a mechanical pump is not so easy and reliable. In the realm of nano-tech materials, ferrofluids have unique properties in both liquids and solids and have potential applications for MEMS/NEMS devices. This paper presents two new types of concepts, a micro-flowmeter based on a micro-turbine made using MEMS technology and the other is a micro-pump based on ferrofluidic actuation. In our first device an optical photovoltaic sensor has also been integrated with this device, and the micro-turbine rotates with a speed of 50000 rpm. We have fabricated a ferrofluid-based glass micro-pump of size 20 × 20 × 10 mm^{3}, in which micro actuation is electrically controlled by NdFeB (N50) permanent magnets (diameter 5 × 3 mm, B_{r} = 1400 mT, coercive field H_c=840 ,kA/m) with a ferrofluid bearing. The device is able to pump the fluid at the rate of 10 μ L/actuation. Figs 3, Refs 19.

  20. STEAM: a software tool based on empirical analysis for micro electro mechanical systems

    NASA Astrophysics Data System (ADS)

    Devasia, Archana; Pasupuleti, Ajay; Sahin, Ferat

    2006-03-01

    In this research a generalized software framework that enables accurate computer aided design of MEMS devices is developed. The proposed simulation engine utilizes a novel material property estimation technique that generates effective material properties at the microscopic level. The material property models were developed based on empirical analysis and the behavior extraction of standard test structures. A literature review is provided on the physical phenomena that govern the mechanical behavior of thin films materials. This survey indicates that the present day models operate under a wide range of assumptions that may not be applicable to the micro-world. Thus, this methodology is foreseen to be an essential tool for MEMS designers as it would develop empirical models that relate the loading parameters, material properties, and the geometry of the microstructures with its performance characteristics. This process involves learning the relationship between the above parameters using non-parametric learning algorithms such as radial basis function networks and genetic algorithms. The proposed simulation engine has a graphical user interface (GUI) which is very adaptable, flexible, and transparent. The GUI is able to encompass all parameters associated with the determination of the desired material property so as to create models that provide an accurate estimation of the desired property. This technique was verified by fabricating and simulating bilayer cantilevers consisting of aluminum and glass (TEOS oxide) in our previous work. The results obtained were found to be very encouraging.

  1. Failure analysis of radio frequency (rf) micro-electro-mechanical systems (MEMS)

    NASA Astrophysics Data System (ADS)

    Walraven, Jeremy A.; Cole, Edward I., Jr.; Sloan, Lynn R.; Hietala, Susan L.; Tigges, Chris P.; Dyck, Christopher W.

    2001-10-01

    MEMS are rapidly emerging as critical components in the telecommunications industry. This enabling technology is currently being implemented in a variety of product and engineering applications. MEMS are currently being used as optical switches to reroute light, tunable filters, and mechanical resonators. Radio frequency (RF) MEMS must be compatible with current Gallium Arsenide (GaAs) microwave integrated circuit (MMIC) processing technologies for maximum integration levels. The RF MEMS switch discussed in this paper was fabricated using various layers of polyimide, silicon oxynitride (SiON), gold, and aluminum monolithically fabricated on a GaAs substrate. Fig. 1 shows a metal contacting series switch. This switch consists of gold signal lines (transmission lines), and contact metallization. SiON was deposited to form the fixed-fixed beam, and aluminum was deposited to form the top actuation electrode. To ensure product performance and reliability, RF MEMS switches are tested at both the wafer and package levels. Various processing irregularities may pass the visual inspection but fail electrical testing. This paper will focus on the failure mechanisms found in the first generation of RF MEMS developed at Sandia National Laboratories. Various tools and techniques such as scanning electron microscopy (SEM), resistive contrast imaging (RCI), focused ion beam (FIB), and thermally-induced voltage alteration (TIVA) have been employed to diagnose the failure mechanisms. The analysis performed using these tools and techniques led to corrective actions implemented in the next generation of RF MEMS metal contacting series switches.

  2. Microwave and Millimeter-Wave Micro-Electro-Mechanical (MEMS) Systems

    NASA Astrophysics Data System (ADS)

    Rebeiz, Gabriel M.

    2002-03-01

    The talk will describe the recent advances in RF MEMS from the physics and microwave perspective. RF MEMS are very small micromechanical devices (micron or nm size) which are used as high-Q resonators, very low-loss switches, and high-Q variable capacitors at RF to mm-wave frequencies. RF MEMS is well understood from a circuit perspective, and many state-of-the-art circuits employing a large number of MEMS switches and varactors have now been demonstrated. However, there are several areas related to the dynamic mechanical analysis of MEMS devices, contact physics, and reliability which are not well understood. The talk will summarize the recent challenges in RF MEMS, especially when they are taken to the nm scale.

  3. Micro-electro-mechanical system (MEMS) component research and development for army missile applications

    NASA Astrophysics Data System (ADS)

    Hudson, Tracy D.; McMillen, Deanna K.; Ashley, Paul R.; Ruffin, Paul B.; Baeder, Janet

    1999-07-01

    The US Army Aviation and Missile Command Missile Research, Development and Engineering Center has identified MEMS as an emerging technology with high potential for fulfilling the mission of future missiles. The technology holds the promise of reducing the size, weight, cost, and power requirements for performing existing functions in Army missile systems, as well las providing opportunities for new computing, sensing, and actuation functions that cannot be achieved with conventional electromechanical technology. MEMS will enable the Army's next generation of smaller and lighter missiles. The military market drives the thrust for development of miniature sensor with applications such as: competent and smart munitions, aircraft and missile autopilots, tactical missile guidance, fire control system, platform stabilization, smart structures with embedded inertial sensors, missile system health monitoring, missile and ground-based radar, radio frequency seekers, aerodynamic flow control, IR imagers, and multiple intelligent small projectiles. Current efforts at AMCOM include the development of MEMS-based inertial components to include accelerometers with wide dynamic range, tactical grade gyros with high rate range, and miniature three-axis inertial measurement unit with common interface electronics. Performance requirements of such components will be presented in terms of current and future Army missile systems. Additional MEMS based efforts under investigation at AMCOM include missile storage health monitoring, RF MEMS components, encoders for actuators, and aerodynamic flow control will also be discussed.

  4. Of magnetic imaging system experiments and micro electro-mechanical systems "of mise and MEMS"

    NASA Astrophysics Data System (ADS)

    Patterson, William C.

    Magnetic fields can occur over an extremely broad range of amplitudes, and spatial and temporal scales. Practical scientific and engineering systems have fields ranging in strength from pico-tesla to hundreds of tesla. Furthermore, spatial variations can range in scale from nanometers to tens of meters, and temporal variations can range from picoseconds to hours. Due to these large variations, many different devices and methods have been previously designed for measuring and mapping magnetic fields. The primary application area for the systems developed here is magnetic microsystems. Such systems make use of one or more microscale electromagnets, soft magnets, and/or permanent magnets for sensors, actuators, inductors, electronics, biomedical devices, etc. A single magnet dimension may range from one mum to hundreds of mum, and the overall area of interest may span over distances of millimeters to centimeters. To map the stray fields from such structures, a field measurement tool must be capable of measuring fields ranging from mT to T, while mapping over distances of millimeters with a spatial resolution of approximately one mum. This current study is focused only on static fields, but time-varying fields are of great interest and could be addressed in further research. This research focuses on the development of two tools that meet the requirements of microscale magnetic measurements. The first tool is based on an optical method and excels at extremely rapid measurements of large spatial regions. The second tool is a raster based system that focuses on high magnetic and spatial accuracy. The optical system quantitatively maps the stray magnetic fields of microscale magnetic structures with field resolution down to 50 muT and spatial resolution down to 4 mum. The system uses a magneto-optical indicator film (MOIF) in conjunction with an upright reflective polarizing light microscope to generate optical images of the magnetic field perpendicular to the image plane. A novel single-light-path construction and discrete multi-image polarimetry processing method are used to extract quantitative areal field measurements from the optical images. The integrated system, including the equipment, image analysis software, and experimental methods are described. MOIFs with three different magnetic field ranges are calibrated, and the entire system is validated by measurement of the field patterns from two calibration samples. The final specifications for the MOIF system are: a spacial resolution of 4.2, 6.2, 20.1 mum for each respective MOIF type, a magnetic range of +/-230 mT with the use of the largest saturation MOIF film, magnetic resolution of +/-0.05, +/-0.5, +/-1 mT for each respective MOIF type, and quantification of a 2660 x 2128 mum area within tens of seconds. The raster system, or scanning Hall probe microscope (SHPM), also quantitatively maps the stray magnetic fields of microscale magnetic structures, with field range of +/-1 T and spatial resolution down to 1.6+/-0.1 mum. The system uses a micro Hall sensor to accurately measure the magnetic field perpendicular to the sample surface. The micro Hall sensor is integrated onto the edge of a quartz tuning fork to accurately detect sensor-to-sample contact, allowing precise control of the measurement height. The sample is raster scanned beneath the sensor with a 3-axis stage system for measurement of a spatial magnetic map. The SHPM components completed during the design and construction are: a raster scan system and enclosure, a Novel AC spinning Gaussmeter, a micro Hall probe integrated on a distance-sensing quartz tuning fork, and a self-oscillating excitation circuit for height control. The final specifications for the SHPM system are: raster scan spatial resolution of 0.3 mum, an average sampling speed of one sample per 0.7 seconds, magnetic active area spacial resolution for the smallest active area Hall sensor (nominally one mum) of 1.6+/-0.1 mum, magnetic sensitivity of the 5, 10 mum Hall probes were 0.47+/-0.006, and 0.420+/-009 VT-1A-1 , respectively, although the

  5. Development of Characterization Tools for Reliability Testing of MicroElectroMechanical System Actuators

    SciTech Connect

    Allen, James J.; Eaton, William P.; Smith, Norman F.; Tanner, Danelle M.

    1999-07-26

    Characterization tools have been developed to study the performance characteristics and reliability of surface micromachined actuators. These tools include (1) the ability to electrically stimulate or stress the actuator, (2) the capability to visually inspect the devices in operation, (3) a method for capturing operational information, and (4) a method to extract performance characteristics from the operational information. Additionally, a novel test structure has been developed to measure electrostatic forces developed by a comb drive actuator.

  6. Micro-electro-mechanical bandpass filters for signal processing by standard CMOS process

    NASA Astrophysics Data System (ADS)

    Huang, Tsungwei; Chang, Peizen; Lee, ChiYuan; Xiao, Fuyuan

    2000-06-01

    This investigation fabricates a laminated-suspension microelectromechanical filter by a fully compatible CMOS process. Experimentally, due to the top metal layer begin used as the etch-resistant mask during the subsequent dry etching. Therefore, this study performs maskless etching with plasma and obtains excellent result including high selectivity and full release of the structure. Additionally, the MEMS filter can be driven by applying low-voltage of around 5 volts and a measured center frequency of around 13.1kHz and a quality factor of around 1871 were obtained for a single-comb resonator operate din air. The filter proposed herein has a monolithic integration capability with the relative electric circuits.

  7. Novel Micro ElectroMechanical Systems (MEMS) Packaging for the Skin of the Satellite

    NASA Technical Reports Server (NTRS)

    Darrin, M. Ann; Osiander, Robert; Lehtonen, John; Farrar, Dawnielle; Douglas, Donya; Swanson, Ted

    2004-01-01

    This paper includes a discussion of the novel packaging techniques that are needed to place MEMS based thermal control devices on the skin of various satellites, eliminating the concern associated with potential particulates &om integration and test or the launch environment. Protection of this MEMS based thermal device is achieved using a novel polymer that is both IR transmissive and electrically conductive. This polymer was originally developed and qualified for space flight application by NASA at the Langley Research Center. The polymer material, commercially known as CPI, is coated with a thin layer of ITO and sandwiched between two window-like frames. The packaging of the MEMS based radiator assembly offers the benefits of micro-scale devices in a chip on board fashion, with the level of protection generally found in packaged parts.

  8. Surface Micro-Machining: Progress Towards Micro-Electro Mechanical Systems

    NASA Technical Reports Server (NTRS)

    Doscher, James

    1995-01-01

    Surface micromachining is a technique for building electromechanical systems in silicon. A number of electromechanical systems have been implemented in miniature using the fundamental structural building blocks of tensile and non-tensile springs, differential capacitance sensing cells, and electrostatic drive. The integration of complicated mechanical structures and electrical circuits onto a single chip is expected to improve reliability and testability of systems. Reduction in interconnect wiring, the increased use of automation, and the inherent reliability of integrated circuits will all contribute to increased reliability of systems.

  9. Virtual Mirrors

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2010-01-01

    The multiple-reflection photograph in Fig. 1 was taken in an elevator on board the cruise ship Norwegian Jade in March 2008. Three of the four walls of the elevator were mirrored, allowing me to see the combination of two standard arrangements of plane mirrors: two mirrors set at 90 degrees to each other and two parallel mirrors. Optical phenomena…

  10. A nano-scale mirror-like surface of Ti–6Al–4V attained by chemical mechanical polishing

    NASA Astrophysics Data System (ADS)

    Chenliang, Liang; Weili, Liu; Shasha, Li; Hui, Kong; Zefang, Zhang; Zhitang, Song

    2016-05-01

    Metal Ti and its alloys have been widely utilized in the fields of aviation, medical science, and micro-electro-mechanical systems, for its excellent specific strength, resistance to corrosion, and biological compatibility. As the application of Ti moves to the micro or nano scale, however, traditional methods of planarization have shown their short slabs. Thus, we introduce the method of chemical mechanical polishing (CMP) to provide a new way for the nano-scale planarization method of Ti alloys. We obtain a mirror-like surface, whose flatness is of nano-scale, via the CMP method. We test the basic mechanical behavior of Ti–6Al–4V (Ti64) in the CMP process, and optimize the composition of CMP slurry. Furthermore, the possible reactions that may take place in the CMP process have been studied by electrochemical methods combined with x-ray photoelectron spectroscopy (XPS). An equivalent circuit has been built to interpret the dynamic of oxidation. Finally, a model has been established to explain the synergy of chemical and mechanical effects in the CMP of Ti–6Al–4V. Project supported by the National Major Scientific and Technological Special Project during the Twelfth Five-year Plan Period of China (Grant No. 2009ZX02030-1), the National Natural Science Foundation of China (Grant No. 51205387), the Support by Science and Technology Commission of Shanghai City, China (Grant No. 11nm0500300), and the Science and Technology Commission of Shanghai City, China (Grant No. 14XD1425300).

  11. Mirror mount

    DOEpatents

    Kuklo, Thomas C.; Bender, Donald A.

    1994-01-01

    A unique lens or mirror mount having adjustable constraints at two key locations to allow for "X" and "Y" tilts of the mirror only. The device uses two pair of flexures of a type such that the pivots of the mirror gimble are rigidly fixed in all planes allowing the device to have zero stacking tolerance and zero wear over time.

  12. Einstein's Mirror

    ERIC Educational Resources Information Center

    Gjurchinovski, Aleksandar; Skeparovski, Aleksandar

    2008-01-01

    Reflection of light from a plane mirror in uniform rectilinear motion is a century-old problem, intimately related to the foundations of special relativity. The problem was first investigated by Einstein in his famous 1905 paper by using the Lorentz transformations to switch from the mirror's rest frame to the frame where the mirror moves at a…

  13. Discrete control of linear distributed systems with application to the deformable primary mirror of a large orbiting telescope. Ph.D. Thesis - Rhode Island Univ.

    NASA Technical Reports Server (NTRS)

    Creedon, J. F.

    1970-01-01

    The results are presented of a detailed study of the discrete control of linear distributed systems with specific application to the design of a practical controller for a plant representative of a telescope primary mirror for an orbiting astronomical observatory. The problem of controlling the distributed plant is treated by employing modal techniques to represent variations in the optical figure. Distortion of the mirror surface, which arises primarily from thermal gradients, is countered by actuators working against a backing structure to apply a corrective force distribution to the controlled surface. Each displacement actuator is in series with a spring attached to the mirror by means of a pad intentionally introduced to restrict the excitation of high-order modes. Control is exerted over a finite number of the most significant modes.

  14. Chiral mirrors

    SciTech Connect

    Plum, Eric; Zheludev, Nikolay I.

    2015-06-01

    Mirrors are used in telescopes, microscopes, photo cameras, lasers, satellite dishes, and everywhere else, where redirection of electromagnetic radiation is required making them arguably the most important optical component. While conventional isotropic mirrors will reflect linear polarizations without change, the handedness of circularly polarized waves is reversed upon reflection. Here, we demonstrate a type of mirror reflecting one circular polarization without changing its handedness, while absorbing the other. The polarization-preserving mirror consists of a planar metasurface with a subwavelength pattern that cannot be superimposed with its mirror image without being lifted out of its plane, and a conventional mirror spaced by a fraction of the wavelength from the metasurface. Such mirrors enable circularly polarized lasers and Fabry-Pérot cavities with enhanced tunability, gyroscopic applications, polarization-sensitive detectors of electromagnetic waves, and can be used to enhance spectroscopies of chiral media.

  15. Mirror mount

    DOEpatents

    Kuklo, T.C.; Bender, D.A.

    1994-10-04

    A unique lens or mirror mount having adjustable constraints at two key locations to allow for ''X'' and ''Y'' tilts of the mirror only is disclosed. The device uses two pair of flexures of a type such that the pivots of the mirror gimble are rigidly fixed in all planes allowing the device to have zero stacking tolerance and zero wear over time. 4 figs.

  16. The design and simulation of single detector MIR spectrometer based on MEMS scanning mirror

    NASA Astrophysics Data System (ADS)

    Zhang, Zhong-wei; Wen, Zhi-yu; Zeng, Tian-ling; Wei, Kang-lin

    2011-08-01

    Infrared (IR) spectrometers are very important optical equipments that can be used in industry, science, medicine, agriculture, biology and food safety etc., and the market is growing. However, most traditional IR spectrometers, such as Fourier transform spectrometer (FTS) that based on Michelson interferometer principle and scanning monochromator that based on grating scanning, are expensive, relative large volume, and stationary, which can't meet the requirements of specific application such as rapidity, special environment and some special samples. To overcome these drawbacks, innovatory technology-micro electro mechanical systems (MEMS) technology was used in micro IR spectrometers in the past few years. And several prototypes and products that based on several operational principles have been emerged. In this paper, a novel IR micro spectrometer which based on MEMS technology and used single element detector was presented over a wide spectral range (from 2500nm to 5000nm) in the mid infrared (MIR) wavelength regime, and the optical system of it was designed on the basis of traditional scanning monochromator principle. In the optical system, there is a highlighted characteristic that dual spherical focus mirror was used to focus the diffraction light of the diffraction grating, which improved the spectral resolution of the optical system. Finally, using Zemax optical software, three torsion angle locations were selected to simulate the optical system of the spectrometer with the slit's size 0.1mm×1mm. The simulation result indicated that in the whole wavelength range the spectral resolution of the optical system was less than 30nm, and a high accuracy MIR spectrometer with compact volume will be realized in future hopefully.

  17. Membrane Mirrors With Bimorph Shape Actuators

    NASA Technical Reports Server (NTRS)

    Yang, Eui-Hyeok

    2003-01-01

    Deformable mirrors of a proposed type would be equipped with relatively-large-stroke microscopic piezoelectric actuators that would be used to maintain their reflective surfaces in precise shapes. These mirrors would be members of the class of MEMS-DM (for microelectromechanical system deformable mirror) devices, which offer potential for a precise optical control in adaptive-optics applications in such diverse fields as astronomy and vision science. The proposed mirror would be fabricated, in part, by use of a membrane-transfer technique. The actuator design would contain bimorph-type piezoelectric actuators.

  18. Magic Mirrors

    ERIC Educational Resources Information Center

    Mills, Allan

    2011-01-01

    "Magic mirrors" were so named because, when they were positioned to throw a reflected patch of sunlight on a nearby wall, this area contained an outline of a design cast on the back of the (bronze) mirror. Investigations begun in the 19th century showed that this was a response to heavy localized pressures exerted on the face of the thin mirror…

  19. Slumped mirrors

    NASA Astrophysics Data System (ADS)

    Pteancu, Mircea; Dragan, Dorin; Dragan, Olivier; Miron, Andrei; Stanescu, Octavian

    2008-02-01

    The authors discusse the construction of slumped mirrors, their fabrication and testing (polishing and lapping). An important topic of the discussion is thermal fabrication of mirrors by using of matrixes. One of the authors of the entry is combining astronomy and aquariums construction.

  20. Einstein's Mirror

    NASA Astrophysics Data System (ADS)

    Gjurchinovski, Aleksandar; Skeparovski, Aleksandar

    2008-10-01

    Reflection of light from a plane mirror in uniform rectilinear motion is a century-old problem, intimately related to the foundations of special relativity.1-4 The problem was first investigated by Einstein in his famous 1905 paper by using the Lorentz transformations to switch from the mirror's rest frame to the frame where the mirror moves at a constant velocity.5 Einstein showed an intriguing fact that the usual law of reflection would not hold in the case of a uniformly moving mirror, that is, the angles of incidence and reflection of the light would not equal each other. Later on, it has been shown that the law of reflection at a moving mirror can be obtained in various alternative ways,6-10 but none of them seems suitable for bringing this interesting subject into the high school classroom.

  1. The thermal analysis of the Hard X-ray Telescope (HXT) and the investigation of the deformation of the mirror foil due to temperature change

    NASA Astrophysics Data System (ADS)

    Ito, Keitaro; Ogi, Keiji; Awaki, Hisamitsu; Kosaka, Tatsuro; Yamamoto, Yasufumi

    2010-07-01

    The thin film technology called "depth-graded multi-layer" is used to manufacture reflector foils, which are inserted in a hard X-ray telescope. When the temperature of the foil changes from the temperature at which the foil was produced; thermal deformation is induced due to difference of linear coefficient of expansion of its constituents. The deformation causes performance of X-ray image formation to deteriorate. Therefore, it is absolutely imperative to estimate the amount of deformation quantitatively and to establish a method of temperature control for the foil under the thermal environment on orbit. We used the hard X-ray telescope, which is part of the currently-projected the ASTRO-H X-ray satellite, as an example for investigation. The effective method of the HXT thermal control was examined with the thermal analytical software, "Thermal Desktop". The deformation of the foil when the temperature was changed by 1 degree C was predicted by a finite element analysis (FEA). The thermal desktop analysis shows that the overall foil temperature in orbit can be close to the temperature at which the foils were produced (~22degree C) by the newly developed thermal control method. The FEM analysis shows that the prediction of the foil deformation due to a temperature change of 1 degree C is about 8 μm.

  2. Mirror, Mirror on the Wall...?

    ERIC Educational Resources Information Center

    Pflaster, Gail

    1979-01-01

    The study determined the value of using a mirror for speech teaching by recording manner, place, voicing, and blend errors produced by 27 hearing-impaired children (5-13 years old) while imitating consonant-vowel syllables under three conditions (audition alone, audition plus direct vision, and audition plus vision using a mirror). (Author)

  3. Optical properties of relativistic plasma mirrors

    PubMed Central

    Vincenti, H.; Monchocé, S.; Kahaly, S.; Bonnaud, G.; Martin, Ph.; Quéré, F.

    2014-01-01

    The advent of ultrahigh-power femtosecond lasers creates a need for an entirely new class of optical components based on plasmas. The most promising of these are known as plasma mirrors, formed when an intense femtosecond laser ionizes a solid surface. These mirrors specularly reflect the main part of a laser pulse and can be used as active optical elements to manipulate its temporal and spatial properties. Unfortunately, the considerable pressures exerted by the laser can deform the mirror surface, unfavourably affecting the reflected beam and complicating, or even preventing, the use of plasma mirrors at ultrahigh intensities. Here we derive a simple analytical model of the basic physics involved in laser-induced deformation of a plasma mirror. We validate this model numerically and experimentally, and use it to show how such deformation might be mitigated by appropriate control of the laser phase. PMID:24614748

  4. Optical properties of relativistic plasma mirrors.

    PubMed

    Vincenti, H; Monchocé, S; Kahaly, S; Bonnaud, G; Martin, Ph; Quéré, F

    2014-01-01

    The advent of ultrahigh-power femtosecond lasers creates a need for an entirely new class of optical components based on plasmas. The most promising of these are known as plasma mirrors, formed when an intense femtosecond laser ionizes a solid surface. These mirrors specularly reflect the main part of a laser pulse and can be used as active optical elements to manipulate its temporal and spatial properties. Unfortunately, the considerable pressures exerted by the laser can deform the mirror surface, unfavourably affecting the reflected beam and complicating, or even preventing, the use of plasma mirrors at ultrahigh intensities. Here we derive a simple analytical model of the basic physics involved in laser-induced deformation of a plasma mirror. We validate this model numerically and experimentally, and use it to show how such deformation might be mitigated by appropriate control of the laser phase. PMID:24614748

  5. Novel unimorph adaptive mirrors for astronomy applications

    NASA Astrophysics Data System (ADS)

    Rausch, Peter; Verpoort, Sven; Wittrock, Ulrich

    2012-07-01

    We have developed a new type of unimorph deformable mirror for the correction of low-order Zernike modes. The mirror features a clear aperture of 50 mm combined with large peak-to-valley amplitudes of up to 35 μm. Newly developed fabrication processes allow the use of prefabricated, coated, super-polished glass substrates. The mirror's unique features suggest the use in several astronomical applications like the compensation of atmospheric aberrations seen by laser beacons and the use in woofer-tweeter systems. Additionally, the design enables an efficient correction of the inevitable wave-front error imposed by the floppy structure of primary mirrors in future large space telescopes. We have modeled the mirror by using analytical as well as finite element models. We will present design, key features and manufacturing steps of the deformable mirror.

  6. Mirror mount

    DOEpatents

    Humpal, H.H.

    1987-11-10

    A mirror mount is provided that allows free pitch, yaw and roll motion of the mirror while keeping the location of a point on the surface of the mirror fixed in the rest frame of reference of the mount. Yaw movement is provided by two yaw cylinders that are bearing mounted to provide rotation. Pitch and roll motion is provided by a spherically annular shell that is air bearing mounted to move between a clamp and an upper pedestal bearing. The centers of curvature of the spherical surfaces of the shell lie upon the point. Pitch motion and roll motion are separately and independently imparted to mirror by a pair of pitch paddles and a pair of roll paddles that are independently and separately moved by control rods driven by motors. 5 figs.

  7. Mirror mount

    DOEpatents

    Humpal, H.H.

    1986-03-21

    A mirror mount is provided that allows free pitch, yaw and roll motion of the mirror while keeping the location of a point on the surface of the mirror fixed in the rest frame of reference of the mount. Yaw movement is provided by two yaw cylinders that are bearing mounted to provide rotation. Pitch and roll motion is provided by a spherically annular shell that is air bearing mounted to move between a clamp and an upper pedestal bearing. The centers of curvature of the spherical surfaces of the shell lie upon the point. Pitch motion and roll motion are separately and independently imparted to mirror by a pair of pitch paddles and a pair of roll paddles that are independently and separately moved by control rods driven by motors.

  8. Mirror mount

    DOEpatents

    Humpal, Harold H.

    1987-01-01

    A mirror mount (10) is provided that allows free pitch, yaw and roll motion of the mirror (28) while keeping the location of a point (56) on the surface of the mirror (28) fixed in the rest frame of reference of the mount (10). Yaw movement is provided by two yaw cylinders (30,32) that are bearing (52) mounted to provide rotation. Pitch and roll motion is provided by a spherically annular shell (42) that is air bearing (72,74) mounted to move between a clamp (60) and an upper pedestal bearing (44). The centers of curvature of the spherical surfaces of the shell (42) lie upon the point (56). Pitch motion and roll motion are separately and independently imparted to mirror (28) by a pair of pitch paddles (34) and a pair of roll paddles (36) that are independently and separately moved by control rods (76,80) driven by motors (78,82).

  9. Morphing of Segmented Bimorph Mirrors

    NASA Astrophysics Data System (ADS)

    Rodrigues, Gonçalo; Bastaits, Renaud; Preumont, André

    2010-08-01

    Atmospheric turbulence compensation for the next generation of terrestrial telescopes (30-40 m diameter) will require deformable mirrors of increasing size and a number of actuators reaching several thousands. However, the mere extrapolation of existing designs leads to complicated and extremely expensive mirrors. This article discusses an alternative solution based on the use of segmented identical hexagonal bimorph mirrors. This allows to indefinitely increase the degree of correction while maintaining the first mechanical resonance at the level of a single segment, and shows an increase in price only proportional to the number of segments. Extensive simulations using random turbulent screens show that the segmentation produces only moderate reductions of the Strehl number, compared to a monolithic bimorph mirror with the same number of actuators (S = 0.86 instead of S = 0.89 in this study).

  10. Thermal analysis of a 4m honeycomb telescope primary mirror

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Xian, Hao

    2012-09-01

    Thermal characteristics of a 4m class honeycomb telescope primary mirror are presented. A 3 dimensional finite elements model of the primary mirror with the varying ambient air temperature as the boundary conditions is used for the numerical simulations. Every night's air temperature profile has been detected in 2009 in Gaomeigu observatory site. Four typical nights' air temperature profiles in different seasons are chose as the boundary conditions in finite element simulation. Temperature difference between primary mirror's optical surface and ambient air is studied, as well as the axial temperature difference inner the mirror blank and radial temperature difference on the optical surface. Primary mirror seeing phenomenon results from the temperature difference between primary mirror's optical surface and the ambient air is discussed. Thermal deformations due to temperature gradient of the primary mirror are analyzed by the finite element model. Axial thermal deformations on the optical surface are discussed in detail. Thermal deformation would induce the optical surface of primary mirror to distort from the normal shape, and lead to large observation image quality degradation. Primary mirror seeing with the turbulence near the optical surface would introduce wavefront aberration and deteriorate the final observation image. In order to reduce mirror seeing and thermal deformation, it is necessary to design a thermal control system for primary mirror. The thermal and structural analysis result will be valuable in designing primary mirror's thermal control system.

  11. Mirror Technology

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Under a NASA contract, MI-CVD developed a process for producing bulk silicon carbide by means of a chemical vapor deposition process. The technology allows growth of a high purity material with superior mechanical/thermal properties and high polishability - ideal for mirror applications. The company employed the technology to develop three research mirrors for NASA Langley and is now marketing it as CVD SILICON CARBIDE. Its advantages include light weight, thermal stability and high reflectivity. The material has nuclear research facility applications and is of interest to industrial users of high power lasers.

  12. Support Technique of Giant Sector-Shaped Segmented Mirror Telescope

    NASA Astrophysics Data System (ADS)

    Sun, Shou-Xiong; Wang, Guo-Min

    2008-06-01

    Based on the segment mirror request of a giant telescope, comparing hexagonal segments with sector-shaped segments, the difference is found. The finite element method was used to analyze the sector-segment mirror deformation under the gravity. The principal aim is to optimize the numbers of the support points and the array of the support. Three schemes, models with 18, 24, and 27 points, are compared by calculating the mirror deformation under the gravity. According to the calculation, the model with 27 points is the best one under which the mirror surface deformation is less than 10 nm, which meets the specification. Then, the mirror surface deformation was calculated under the gravity with the optimized axial support and the lateral support in the central diaphragm when the primary mirror points to three different directions: horizontal, vertical and 45°. The calculation results show that all the shape changes in the sector-shaped submirror are less than 10 nm.

  13. Conicoid Mirrors

    ERIC Educational Resources Information Center

    Castano, Diego J.; Hawkins, Lawrence C.

    2011-01-01

    The first-order equation relating object and image location for a mirror of arbitrary conic-sectional shape is derived. It is also shown that the parabolic reflecting surface is the only one free of aberration and only in the limiting case of distant sources. (Contains 3 figures.)

  14. Mirror Support

    NASA Technical Reports Server (NTRS)

    Baron, Richard L. (Inventor)

    2013-01-01

    Disclosed herein is a method of making a mirror support comprising a composite, the composite comprising a plurality of carbon nanotubes, wherein at least two of the plurality of carbon nanotubes are bonded to each other through a bridging moiety bound to each of the two carbon nanotubes, and a laminate comprising the composite.

  15. MEMS practice: from the lab to the telescope

    NASA Astrophysics Data System (ADS)

    Morzinski, Katie M.; Norton, Andrew P.; Evans, Julia W.; Reza, Layra; Severson, Scott A.; Dillon, Daren; Reinig, Marc; Gavel, Donald T.; Cornelissen, Steven; Macintosh, Bruce A.; Max, Claire E.

    2012-03-01

    Micro-electro-mechanical systems (MEMS) technology can provide for deformable mirrors (DMs) with excellent performance within a favorable economy of scale. Large MEMS-based astronomical adaptive optics (AO) systems such as the Gemini Planet Imager are coming on-line soon. As MEMS DM end-users, we discuss our decade of practice with the micromirrors, from inspecting and characterizing devices to evaluating their performance in the lab. We also show MEMS wavefront correction on-sky with the "Villages" AO system on a 1-m telescope, including open-loop control and visible-light imaging. Our work demonstrates the maturity of MEMS technology for astronomical adaptive optics.

  16. Topology optimization design of a space mirror

    NASA Astrophysics Data System (ADS)

    Liu, Jiazhen; Jiang, Bo

    2015-11-01

    As key components of the optical system of the space optical remote sensor, Space mirrors' surface accuracy had a direct impact that couldn't be ignored of the imaging quality of the remote sensor. In the future, large-diameter mirror would become an important trend in the development of space optical technology. However, a sharp increase in the mirror diameter would cause the deformation of the mirror and increase the thermal deformation caused by temperature variations. A reasonable lightweight structure designed to ensure the optical performance of the system to meet the requirements was required. As a new type of lightweight approach, topology optimization technology was an important direction of the current space optical remote sensing technology research. The lightweight design of rectangular mirror was studied. the variable density method of topology optimization was used. The mirror type precision of the mirror assemblies was obtained in different conditions. PV value was less than λ/10 and RMS value was less than λ/50(λ = 632.8nm). The results show that the entire The mirror assemblies can achieve a sufficiently high static rigidity, dynamic stiffness and thermal stability and has the capability of sufficient resistance to external environmental interference . Key words: topology optimization, space mirror, lightweight, space optical remote sensor

  17. Acceleration of dormant storage effects to address the reliability of silicon surface micromachined Micro-Electro-Mechanical Systems (MEMS).

    SciTech Connect

    Cox, James V.; Candelaria, Sam A.; Dugger, Michael Thomas; Duesterhaus, Michelle Ann; Tanner, Danelle Mary; Timpe, Shannon J.; Ohlhausen, James Anthony; Skousen, Troy J.; Jenkins, Mark W.; Jokiel, Bernhard, Jr.; Walraven, Jeremy Allen; Parson, Ted Blair

    2006-06-01

    Qualification of microsystems for weapon applications is critically dependent on our ability to build confidence in their performance, by predicting the evolution of their behavior over time in the stockpile. The objective of this work was to accelerate aging mechanisms operative in surface micromachined silicon microelectromechanical systems (MEMS) with contacting surfaces that are stored for many years prior to use, to determine the effects of aging on reliability, and relate those effects to changes in the behavior of interfaces. Hence the main focus was on 'dormant' storage effects on the reliability of devices having mechanical contacts, the first time they must move. A large number ({approx}1000) of modules containing prototype devices and diagnostic structures were packaged using the best available processes for simple electromechanical devices. The packaging processes evolved during the project to better protect surfaces from exposure to contaminants and water vapor. Packages were subjected to accelerated aging and stress tests to explore dormancy and operational environment effects on reliability and performance. Functional tests and quantitative measurements of adhesion and friction demonstrated that the main failure mechanism during dormant storage is change in adhesion and friction, precipitated by loss of the fluorinated monolayer applied after fabrication. The data indicate that damage to the monolayer can occur at water vapor concentrations as low as 500 ppm inside the package. The most common type of failure was attributed to surfaces that were in direct contact during aging. The application of quantitative methods for monolayer lubricant analysis showed that even though the coverage of vapor-deposited monolayers is generally very uniform, even on hidden surfaces, locations of intimate contact can be significantly depleted in initial concentration of lubricating molecules. These areas represent defects in the film prone to adsorption of water or contaminants that can cause movable structures to adhere. These analysis methods also indicated significant variability in the coverage of lubricating molecules from one coating process to another, even for identical processing conditions. The variability was due to residual molecules left in the deposition chamber after incomplete cleaning. The coating process was modified to result in improved uniformity and total coverage. Still, a direct correlation was found between the resulting static friction behavior of MEMS interfaces, and the absolute monolayer coverage. While experimental results indicated that many devices would fail to start after aging, the modeling approach used here predicted that all the devices should start. Adhesion modeling based upon values of adhesion energy from cantilever beams is therefore inadequate. Material deposition that bridged gaps was observed in some devices, and potentially inhibits start-up more than the adhesion model indicates. Advances were made in our ability to model MEMS devices, but additional combined experimental-modeling studies will be needed to advance the work to a point of providing predictive capability. The methodology developed here should prove useful in future assessments of device aging, however. Namely, it consisted of measuring interface properties, determining how they change with time, developing a model of device behavior incorporating interface behavior, and then using the age-aware interface behavior model to predict device function.

  18. Growth of cubic silicon carbide on oxide using polysilicon as a seed layer for micro-electro-mechanical machine applications

    NASA Astrophysics Data System (ADS)

    Frewin, C. L.; Locke, C.; Wang, J.; Spagnol, P.; Saddow, S. E.

    2009-08-01

    The growth of highly oriented 3C-SiC directly on an oxide release layer, composed of a 20-nm-thick poly-Si seed layer and a 550-nm-thick thermally deposited oxide on a (1 1 1)Si substrate, was investigated as an alternative to using silicon-on-insulator (SOI) substrates for freestanding SiC films for MEMS applications. The resulting SiC film was characterized by X-ray diffraction (XRD) with the X-ray rocking curve of the (1 1 1) diffraction peak displaying a FWHM of 0.115° (414″), which was better than that for 3C-SiC films grown directly on (1 1 1)Si during the same deposition process. However, the XRD peak amplitude for the 3C-SiC film on the poly-Si seed layer was much less than for the (1 1 1)Si control substrate, due to slight in-plane misorientations in the film. Surprisingly, the film was solely composed of (1 1 1) 3C-SiC grains and possessed no 3C-SiC grains oriented along the <3 1 1> and <1 1 0> directions which were the original directions of the poly-Si seed layer. With this new process, MEMS structures such as cantilevers and membranes can be easily released leaving behind high-quality 3C-SiC structures.

  19. Efficient reduced order modeling for system simulation of micro-electro-mechanical systems (MEMS) from FEM models

    NASA Astrophysics Data System (ADS)

    Affour, Bachar; Nachtergaele, Philippe; Spirkovitch, Stevan; Ostergaard, Dale; Gyimesi, Miklos P.

    2000-04-01

    System designers need access to high-fidelity behavioral models in order to simulate system of MEMS, electronics and packaging. Therefore, the need exists to create behavioral models that provide accurate harmonic and time-domain solutions in a fast and efficient manner. In the MEMSCAP MEMS design suite, the EDD family of tools enables the generation of non-linear dynamic behavioral models from models with a hierarchically lower level of abstraction or measured data. In this paper, we report on a new module of EDD, the ANSYS ModelBuilder, which is embedded in the ANSYS Multi-physics tool set. The module reduces the dimensionality of FEM models built in ANSYS and writes them in popular modeling languages such as HDL-A, SPICE, VHDL-AMS and Verilog-A. We illustrate the capabilities of our new tool by utilizing it to develop two system level examples and compare the results to the full 3D descriptions.

  20. Detection of sub-ppm traces of aqueous heavy-metal ions using micro-electro-mechanical beam resonators

    NASA Astrophysics Data System (ADS)

    Rahafrooz, Amir; Pourkamali, Siavash

    2009-11-01

    Capacitive silicon micro-mechanical resonators have been utilized in this work as ultra-sensitive mass sensors for the detection of trace amounts of copper ions in water samples. The approach is based on the reduction of aqueous metal ions by the silicon in a resonant structure and consequently deposition of a very thin metal layer on the resonator surface changing its resonant frequency. Measurements demonstrate successful detection of sub-ppm concentrations of copper(II) ions in water. Relatively large frequency shifts (hundreds of ppm) have been measured for resonators exposed to copper concentrations as low as 4 µM (0.26 ppm). An analytical model for the resonant frequency of the resulting complex beams has been derived and used to calculate the thickness of the deposited copper layer based on the measured frequency shifts. The model shows that the measured frequency shifts correspond to only a few atomic layers of copper (as thin as ~7 Å) deposited on the resonator surfaces. This corresponds to a mass sensitivity of more than 4000 Hz µg-1 cm-2 which is much larger than the highest mass sensitivities measured for quartz crystal microbalances.

  1. Applicability of Time-Averaged Holography for Micro-Electro-Mechanical System Performing Non-Linear Oscillations

    PubMed Central

    Palevicius, Paulius; Ragulskis, Minvydas; Palevicius, Arvydas; Ostasevicius, Vytautas

    2014-01-01

    Optical investigation of movable microsystem components using time-averaged holography is investigated in this paper. It is shown that even a harmonic excitation of a non-linear microsystem may result in an unpredictable chaotic motion. Analytical results between parameters of the chaotic oscillations and the formation of time-averaged fringes provide a deeper insight into computational and experimental interpretation of time-averaged MEMS holograms. PMID:24451467

  2. Mirror, Mirror, on the Wall.

    ERIC Educational Resources Information Center

    Flowers, Jim; Rose, M. Annette

    1998-01-01

    Students use tables of anthropometric data, their own measurements, underlying principles of physics, and math to solve a problem. The problem is to determine the height of a wall mirror, and where to mount it, so that 90% of the clientele can view their entire length without stretching or bending. (Author)

  3. Focus tunable mirrors made by ionic polymer-metal composite

    NASA Astrophysics Data System (ADS)

    Li, Chung-Min; Su, Guo-Dung

    2014-09-01

    In order to meet modern requirement, electronic products are made smaller and thinner. We used deformable mirrors (DMs) in optical systems that can make camera modules thinner and lighter in electronic products. An Ionic-Polymer Metal Composite (IPMC) plays the critical role in our design of deformable mirrors. It has good bending feature and can be driven by low voltage (usually less than 5 volts). Other technologies such as liquid lenses, MEMS deformable mirrors, and liquid crystal lens, all need higher voltage to reach similar optical power of IPMC. After fabrication of IPMC deformable mirrors, we used PDMS on one surface to improve the surface roughness before reflective metal is deposited. Key characteristics of IPMC deformable mirror are demonstrated in the paper. By coating a silver layer on the smoothed IPMC surface, the reflection is up to 90%. From simulation results, the zoom ratio of this module can be expected 1.8 times. Experimentally, the deformable mirror can be changed from flat to 65 diopters (m-1) by only 3 volts. In this paper, we demonstrated a reflective optical zoom module with three mirrors and two deformable mirrors.

  4. Mirror monochromator

    SciTech Connect

    Mankos, Marian; Shadman, Khashayar

    2014-12-02

    In this SBIR project, Electron Optica, Inc. (EOI) is developing a mirror electron monochromator (MirrorChrom) attachment to new and retrofitted electron microscopes (EMs) for improving the energy resolution of the EM from the characteristic range of 0.2-0.5 eV to the range of 10-50 meV. This improvement will enhance the characterization of materials by imaging and spectroscopy. In particular, the monochromator will refine the energy spectra characterizing materials, as obtained from transmission EMs [TEMs] fitted with electron spectrometers, and it will increase the spatial resolution of the images of materials taken with scanning EMs (SEMs) operated at low voltages. EOI’s MirrorChrom technology utilizes a magnetic prism to simultaneously deflect the electron beam off the axis of the microscope column by 90° and disperse the electrons in proportional to their energies into a module with an electron mirror and a knife-edge. The knife-edge cuts off the tails of the energy distribution to reduce the energy spread of the electrons that are reflected, and subsequently deflected, back into the microscope column. The knife-edge is less prone to contamination, and thereby charging, than the conventional slits used in existing monochromators, which improves the reliability and stability of the module. The overall design of the MirrorChrom exploits the symmetry inherent in reversing the electron trajectory in order to maintain the beam brightness – a parameter that impacts how well the electron beam can be focused downstream onto a sample. During phase I, EOI drafted a set of candidate monochromator architectures and evaluated the trade-offs between energy resolution and beam current to achieve the optimum design for three particular applications with market potential: increasing the spatial resolution of low voltage SEMs, increasing the energy resolution of low voltage TEMs (beam energy of 5-20 keV), and increasing the energy resolution of conventional TEMs (beam

  5. Toward a large lightweight mirror for AO: development of a 1m Ni coated CFRP mirror

    NASA Astrophysics Data System (ADS)

    Thompson, S. J.; Doel, A. P.; Brooks, D.; Strangwood, M.

    2008-07-01

    We present our recent developments towards the construction of a large, thin, single-piece mirror for adaptive optics (AO). Our current research program aims to have completed fabrication and testing of a 1m diameter, nickel coated carbon-fibre reinforced cyanate ester resin mirror by the last quarter of 2009. This composite mirror material is being developed to provide a lightweight and robust alternative to thin glass shell mirrors, with the challenge of future large deformable mirrors such as the 2.5m M4 on the E-ELT in mind. A detailed analysis of the material properties of test mirror samples is being performed at the University of Birmingham (UK), the first results of which are discussed and presented here. We discuss the project progress achieved so far, including fabrication of the 1m flat moulds for the replication process, manufacturing and testing methods for 20 cm diameter sample mirrors and system simulations.

  6. Mirror systems

    SciTech Connect

    Howells, M.R.

    1985-12-01

    The physics of VUV and x-ray reflection is reviewed. The main functions of mirrors in synchrotron beamlines are stated briefly and include deflection, filtration, power absorption, formation of a real image of the source, focusing, and collimation. Methods of fabrication of optical surfaces are described. Types of imperfections are discussed, including, aberrations, surface figure inaccuracy, roughness, and degradation due to use. Calculation of the photon beam thermal load, including computer modelling, is considered. 50 refs., 7 figs. (LEW)

  7. Chinese "Magic" Mirrors.

    ERIC Educational Resources Information Center

    Swinson, Derek B.

    1992-01-01

    Chinese "magic" mirrors are made from bronze with the front side a mirror and the reverse side a molded image. When light is reflected from the mirror,the image on the reverse side appears. Discusses reflections of conventional mirrors, possible explanations for the magic mirror phenomenon, and applications of the phenomenon to semiconductor…

  8. Position sensors for segmented mirror

    NASA Astrophysics Data System (ADS)

    Rozière, Didier; Buous, Sébastien; Courteville, Alain

    2004-09-01

    There are currently several projects for giant telescopes with segmented mirrors under way. These future telescopes will have their primary mirror made of several thousand segments. The main advantage of segmentation is that it enables the active control of the whole mirror, so as to suppress the deformations of the support structure due to the wind, gravity, thermal inhomogeneities etc. ..., thus getting the best possible stigmatism. However, providing active control of segmented mirrors requires numerous accurate edges sensors. It is acknowledged that capacitance-based technology nowadays offers the best metrological performances-to-cost ratio. As the leader in capacitive technology, FOGALE nanotech offers an original concept which reduces the cost of instrumentation, sensors and electronics, while keeping a very high level of performances with a manufacturing process completely industrialised. We present here the sensors developed for the Segment Alignment Measurement System (SAMS) of the Southern African Large Telescope (SALT). This patented solution represents an important improvement in terms of cost, to market the Position Sensors for Segmented Mirrors of ELTs, whilst maintaining a very high performance level. We present here the concept, the laboratory qualification, and the first trials on the 7 central segments of SALT. The laboratory results are good, and we are now working on the on-site implementation to improve the immunity of the sensors to environment.

  9. Isospin symmetry in mirror α decays

    NASA Astrophysics Data System (ADS)

    Timofeyuk, N. K.; Descouvemont, P.; Johnson, R. C.

    2007-03-01

    We show that a consequence of isospin symmetry, recently discovered in mirror conjugated one-nucleon decays, can be extended to mirror-conjugated α-particle decays, both virtual and real. For virtual α decays of bound mirror pairs this symmetry manifests itself as a relation between the asymptotic normalization coefficients (ANCs) of α-particle overlap integrals. This relation is given by a simple analytical formula that involves α-particle separation energies and charges of residual nuclei. For bound-unbound mirror pairs, the ANC of a bound nucleus is related to the α width of the mirror unbound level. For unbound mirror pairs we get a new analytical formula that relates the widths of mirror resonances. We test the validity of these analytical formulas against the predictions of a two-body potential and of a many-body microscopic cluster model for several mirror states in Li7-Be7, B11-C11, and F19-Ne19 isotopes. We show that these analytical formulas are valid in many cases but that some deviations can be expected for isotopes with strongly deformed and easily excited cores. In general, the results from microscopic model are not very sensitive to model assumptions and can be used to predict unknown astrophysically relevant cross sections using known information about mirror systems.

  10. Large thin adaptive x-ray mirrors

    NASA Astrophysics Data System (ADS)

    Doel, Peter; Atkins, Carolyn; Thompson, Samantha; Brooks, David; Yao, Jun; Feldman, Charlotte; Willingale, Richard; Button, Tim; Zhang, Dou; James, Ady

    2007-09-01

    This paper describes the progress made in a proof of concept study and recent results of a research program into large active x-ray mirrors that is part of the UK Smart X-ray Optics project. The ultimate aim is to apply the techniques of active/adaptive optics to the next generation of nested shell astronomical X-ray space telescopes. A variety of deformable mirror technologies are currently available, the most promising of which for active X-ray mirrors are probably unimorph and bimorph piezoelectric mirrors. In this type of mirror one or more sheets of piezoelectric material are bonded to or coated with a passive reflective layer. On the back or between the piezoceramic layer/layers are series of electrodes. Application of an electric field causes the piezoelectric material to undergo local deformation thus changing the mirror shape. Starting in 2005 a proof of concept active mirror research program has been undertaken. This work included modelling and development of actively controlled thin shell mirrors. Finite element models of piezo-electric actuated mirrors have been developed and verified against experimental test systems. This has included the modelling and test of piezo-electric hexagonal unimorph segments. Various actuator types and low shrinkage conductive bonding methods have been investigated and laboratory tests of the use of piezo-electric actuators to adjust the form of an XMM-Newton space telescope engineering model mirror shell have been conducted and show that movement of the optics at the required level is achievable. Promising technological approaches have been identified including moulded piezo-ceramics and piezo-electrics fibre bundles.

  11. Double arch mirror study

    NASA Technical Reports Server (NTRS)

    Vukobratovich, D.; Hillman, D.

    1983-01-01

    The development of a method of mounting light weight glass mirrors for astronomical telescopes compatible with the goals of the Shuttle Infrared Telescope Facility (SIRTF) was investigated. A 20 in. diameter double arch lightweight mirror previously fabricated was modified to use a new mount configuration. This mount concept was developed and fabricated. The mounting concept of the double mounting mirror is outlined. The modifications made to the mirror, fabrication of the mirror mount, and room temperature testing of the mirror and mount and the extension of the mirror and mount concept to a full size (40 in. diameter) primary mirror for SIRTF are discussed.

  12. Floating mirror mount

    SciTech Connect

    Koop, D.E.

    1989-01-03

    This patent describes a floating mirror mount for a mirror of a laser is described consisting of: a mirror having a front surface and a back surface, a keeper encircling the mirror and having a peripheral flange engaging the front surface of the mirror when the mirror is not installed in a laser, a retainer positioned rearwardly of the back surface of the mirror and connected to the keeper and having a spring seating surface, spring means engageable with the spring seating surface of the retainer for exerting a resilient biasing force on the mirror, and fastening means for connecting the retainer to the mirror positioning structure of the laser on installation of the mirror mount in the laser.

  13. Silicon Membrane Mirrors with Electrostatic Shape Actuators

    NASA Technical Reports Server (NTRS)

    Yang, Eui-Hyeok

    2003-01-01

    Efforts are under way to develop deformable mirrors equipped with microscopic electrostatic actuators that would be used to maintain their reflective surfaces in precise shapes required for their intended applications. Unlike actuators that depend on properties of materials (e.g., piezoelectric and electrostrictive actuators), electrostatic actuators are effective over a wide temperature range. A mirror of the present type would be denoted a MEMSDM (for microelectromechanical system deformable mirror). The reflective surface of such a mirror would be formed on a single-crystal silicon membrane that would be attached by posts to a silicon actuator membrane that would, in turn, be attached by posts to a rigid silicon base (see figure). The actuator membrane would serve as the upper electrode of a capacitor. Multiple lower electrodes, each occupying a conveniently small fraction of the total area, would be formed on an electrically insulating oxide layer on the base, thereby defining a multiplicity of actuator pixels. The actuator membrane would be corrugated in a pattern that would impart mechanical compliance needed for relaxation of operational and fabrication-induced stresses and to minimize the degree of nonlinearity of deformations. The compliance afforded by the corrugations would also help to minimize the undesired coupling of deformations between adjacent pixels (a practical goal being to keep the influence coefficient between adjacent pixels below 10 percent).

  14. Quality evaluation of spaceborne SiC mirrors (I): analytical examination of the effects on mirror accuracy by variation in the thermal expansion property of the mirror surface.

    PubMed

    Kotani, Masaki; Imai, Tadashi; Katayama, Haruyoshi; Yui, Yukari; Tange, Yoshio; Kaneda, Hidehiro; Nakagawa, Takao; Enya, Keigo

    2013-07-10

    The Japan Aerospace Exploration Agency has studied a large-scale lightweight mirror constructed of reaction-bonded silicon carbide-based material as a key technology in future astronomical and earth observation missions. The authors selected silicon carbide as the promising candidate due to excellent characteristics of specific stiffness and thermal stability. One of the most important technical issues for large-scale ceramic components is the uniformity of the material's property, depending on part and processing. It might influence mirror accuracy due to uneven thermal deformation. The authors conducted systematic case studies for the conditions of CTE by finite element analysis to know the typical influence of material property nonuniformity on mirror accuracy and consequently derived a comprehensive empirical equation for the series of CTE's main factors. In addition, the authors computationally reproduced the mirror accuracy profile of a small prototype mirror shown in cryogenic testing and hereby verified wide-range practical computational evaluation technology of mirror accuracy. PMID:23852191

  15. Kinematic high bandwidth mirror mount

    DOEpatents

    Kuklo, T.C.

    1995-03-21

    An adjustable mirror mount system for a mirror is disclosed comprising a mirror support having a planar surface thereon, a mirror frame containing a mirror and having a planar surface behind the mirror facing the planar surface of the mirror support and parallel to the reflecting surface of the mirror and mounted pivotally to the mirror support at a point central to the frame, a first adjustment means between the mirror support and the mirror frame spaced from the central pivot mount for adjusting the movement of the mirror along one axis lying in the plane of the planar surface of the mirror frame; and a second adjustment means between the mirror support and the mirror frame spaced from the central pivot mount for adjusting the movement of the mirror along a second axis lying in the plane of the planar surface of the mirror frame and perpendicular to the first axis. 7 figures.

  16. Kinematic high bandwidth mirror mount

    DOEpatents

    Kuklo, Thomas C.

    1995-01-01

    An adjustable mirror mount system for a mirror is disclosed comprising a mirror support having a planar surface thereon, a mirror frame containing a mirror and having a planar surface behind the mirror facing the planar surface of the mirror support and parallel to the reflecting surface of the mirror and mounted pivotally to the mirror support at a point central to the frame, a first adjustment means between the mirror support and the mirror frame spaced from the central pivot mount for adjusting the movement of the mirror along one axis lying in the plane of the planar surface of the mirror frame; and a second adjustment means between the mirror support and the mirror frame spaced from the central pivot mount for adjusting the movement of the mirror along a second axis lying in the plane of the planar surface of the mirror frame and perpendicular to the first axis.

  17. Topological Mirror Superconductivity

    NASA Astrophysics Data System (ADS)

    Zhang, Fan; Kane, C. L.; Mele, E. J.

    2013-08-01

    We demonstrate the existence of topological superconductors (SCs) protected by mirror and time-reversal symmetries. D-dimensional (D=1, 2, 3) crystalline SCs are characterized by 2D-1 independent integer topological invariants, which take the form of mirror Berry phases. These invariants determine the distribution of Majorana modes on a mirror symmetric boundary. The parity of total mirror Berry phase is the Z2 index of a class DIII SC, implying that a DIII topological SC with a mirror line must also be a topological mirror SC but not vice versa and that a DIII SC with a mirror plane is always time-reversal trivial but can be mirror topological. We introduce representative models and suggest experimental signatures in feasible systems. Advances in quantum computing, the case for nodal SCs, the case for class D, and topological SCs protected by rotational symmetries are pointed out.

  18. Light, Color, and Mirrors.

    ERIC Educational Resources Information Center

    Tiburzi, Brian; Tamborino, Laurie; Parker, Gordon A.

    2000-01-01

    Describes an exercise in which students can use flashlights, mirrors, and colored paper to discover scientific principles regarding optics. Addresses the concepts of angles of incidence and reflection, colored vs. white light, and mirror images. (WRM)

  19. Attractive characteristics of mirrors

    NASA Astrophysics Data System (ADS)

    Post, R. F.; Ryutov, D. D.

    1994-12-01

    A summary of the attractive characteristics of mirror devices is presented. Recent progress in development of axisymmetric mirror devices is described. Potentialities of mirrors as a basis for D(3)He fusion power generators and high-flux neutron sources for fusion material tests are discussed.

  20. Anastigmatic three-mirror telescope

    NASA Technical Reports Server (NTRS)

    Korsch, D. G. (Inventor)

    1978-01-01

    A three-mirror telescope for extraterrestrial observations is described. An ellipsoidal primary mirror, a hyperbolic secondary mirror, and an ellipsoidal tertiary mirror, produce an image in a conveniently located finite plane for viewing.

  1. Indium Second-Surface Mirrors

    NASA Technical Reports Server (NTRS)

    Bouquet, F. L.; Hasegawa, T.

    1982-01-01

    Second-surface mirrors are formed by vapor deposition of indium onto glass. Mirrors have reflectances comparable to those of ordinary silver or aluminized mirrors and are expected to show superior corrosion resistance. Mirrors may be used in solar concentrators.

  2. Rollable Thin-Shell Nanolaminate Mirrors

    NASA Technical Reports Server (NTRS)

    Hickey, Gregory; Lih, Shyh-Shiuh; Barbee, Troy, Jr.

    2003-01-01

    A class of lightweight, deployable, thin-shell, curved mirrors with built-in precise-shape-control actuators is being developed for high-resolution scientific imaging. This technology incorporates a combination of advanced design concepts in actuation and membrane optics that, heretofore, have been considered as separate innovations. These mirrors are conceived to be stowed compactly in a launch shroud and transported aboard spacecraft, then deployed in outer space to required precise shapes at much larger dimensions (diameters of the order of meters or tens of meters). A typical shell rollable mirror structure would include: (1) a flexible single- or multiple-layer face sheet that would include an integrated reflective surface layer that would constitute the mirror; (2) structural supports in the form of stiffeners made of a shape-memory alloy (SMA); and (3) piezoelectric actuators. The actuators, together with an electronic control subsystem, would implement a concept of hierarchical distributed control, in which (1) the SMA actuators would be used for global shape control and would generate the large deformations needed for the deployment process and (2) the piezoelectric actuators would generate smaller deformations and would be used primarily to effect fine local control of the shape of the mirror.

  3. Stress analysis of spherical-mirror panels

    SciTech Connect

    Parks, V J; Sanford, R J

    1982-04-01

    An experimental analysis is reported of the stresses that occur in elastically deformed, spherically curved glass mirrors for solar energy applications. Bending and membrance stresses generated in forming the glass and the effects of springback are analyzed. In addition, thermal stresses caused by focusing the sun's rays on a small region of the mirrors are analyzed. Methods used in the analysis included the use of grids, photoelasticity, and strain gages. Results of the analysis are compared with a theoretical analysis performed by Shelltech Associates in a parallel effort.

  4. Modeling and structural analysis of honeycomb structure mirror

    NASA Astrophysics Data System (ADS)

    Li, Yeping

    2012-09-01

    In development of large-scale astronomical telescopes, some promising new technology and method such as honeycomb structure mirrors and silicon carbide mirrors are applied for primary mirrors. Especially in space telescopes, the mirror lightweight design is becoming the key technology and honeycomb structure mirrors are normally required more and more to reduce the cost and increase the feasibility of the telescopes system. In this paper, a parameter FEA model of a two meters honeycomb structure mirror has been built, by using the engineering analysis software ANSYS. Through this model, the structural analysis, thermal deformation analysis and the simulation active correction of low-order frequency aberration by the finite element method have been presented.

  5. Mirror Technology Roadmap for NASA's Exoplanet Exploration Program

    NASA Technical Reports Server (NTRS)

    Lawson, Peter R.; Shaklan, Stuart B.; Balasubramanian, K.

    2011-01-01

    There are several possible approaches to designing exoplanet missions: (1) Coronagraphs (2) Interferometers (3) Starshades Wavefront sensing and control is the central concern, not mirror size (1) Starlight suppression with deformable mirrors (2) Thermal and structural stability (3) Metrology for sensing and control Diffraction-limited optical primary mirrors 4-m or larger are needed to detect Earthlike planets (1) Surface figure similar to HST required (2) Smaller primary mirrors can be used with aggressive coronagraph designs, but the stability tolerances become the driving concern (3) Stability tolerances of coronagraphs are greatly reduced when larger primaries are used in conjunction with 8th-order masks Long term vision for large telescope development includes space-based segmented-mirror telescopes using actively-controlled glass segments or silicon carbide hybrid-mirror designs

  6. Final Results of the Ball AMSD Beryllium Mirror

    NASA Technical Reports Server (NTRS)

    Chaney, David M.

    2004-01-01

    The 1.4-meter semi-rigid, beryllium Advanced Mirror System Demonstrator (AMSD) mirror completed initial cryogenic testing at Marshall's X-ray Calibration Facility (XRCF) in August of 2003. Results of this testing show the mirror to have very low cryogenic surface deformation and possess exceptional figure stability. Subsequent to this cryogenic testing beryllium was selected as the material of choice for the James Webb Space Telescope (JWST) multi-segment primary mirror. Therefore, the AMSD mirror was sent back to SSG-Tinsley for additional ambient polishing to JWST requirements. The mirror was successfully polished to less than 22nm rms of low frequency error. Those additional results are presented with comparisons to the JWST requirements.

  7. Water Cooled Mirror Design

    SciTech Connect

    Dale, Gregory E.; Holloway, Michael Andrew; Pulliam, Elias Noel

    2015-03-30

    This design is intended to replace the current mirror setup being used for the NorthStar Moly 99 project in order to monitor the target coupon. The existing setup has limited movement for camera alignment and is difficult to align properly. This proposed conceptual design for a water cooled mirror will allow for greater thermal transfer between the mirror and the water block. It will also improve positioning of the mirror by using flexible vacuum hosing and a ball head joint capable of a wide range of motion. Incorporating this design into the target monitoring system will provide more efficient cooling of the mirror which will improve the amount of diffraction caused by the heating of the mirror. The process of aligning the mirror for accurate position will be greatly improved by increasing the range of motion by offering six degrees of freedom.

  8. Primary mirror alignment and assembly for a multispectral space telescope

    NASA Astrophysics Data System (ADS)

    Lin, Wei-Cheng; Chang, Shenq-Tsong; Chang, Sheng-Hsiung; Chang, Chen-Peng; Lin, Yu-Chuan; Huang, Po-Hsuan; Tsay, Ho-Lin; Chin, Chi-Chieh; Pan, Hsu-Pin; Huang, Ting-Ming

    2013-10-01

    For a currently developing multispectral space Cassegrain telescope, the primary mirror with 450 mm clear aperture is made of Zerodur and lightweighted at a ratio about 50 % to meet both thermal and mass requirement. For this mirror, it is critical to reduce the astigmatism caused from the gravity effect, bonding process and the deformation from the mounting to the main structure of the telescope (main plate). In this article, the primary mirror alignment, MGSE, assembly process and the optical performance test for the primary mirror assembly are presented. The mechanical shim is the interface between the iso-static mount and main plate. It is used to compensate the manufacture errors of components and differences of local co-planarity errors to prevent the stress while iso-static mount (ISM) is screwed to main plate. After primary mirror assembly, an optical performance test method called bench test with novel algorithm is used to analyze the astigmatism caused from the gravity effect and the deformation from the mounting or supporter. In an effort to achieve the requirement for the tolerance in primary mirror assembly, the astigmatism caused from the gravity and deformation by the mounting force could be less than P-V 0.02λ at 633 nm. The consequence of these demonstrations indicates that the designed mechanical ground supported equipment (MGSE) for the alignment and assembly processes meet the critical requirements for primary mirror assembly of the telescope.

  9. Applications of MEMS in segmented mirror space telescopes

    NASA Astrophysics Data System (ADS)

    Agrawal, Brij; Kubby, Joel

    2011-03-01

    Development of space telescopes, such as the Hubble Space Telescope and the James Webb Telescope has been very challenging in terms of cost, schedule, and performance. For several future space missions, larger aperture and lightweight deployable mirrors, in the range of 10-20 meters in diameter with high surface accuracy, are required. In order to achieve lightweight, reduce cost for development and provide performance robustness, actuated hybrid mirror (AHM) technology is under development. The Naval Postgraduate School (NPS) recently received a 3-meter diameter space telescope testbed with six segments that uses an AHM technology. This paper will discuss the work performed at NPS on the surface control of the primary mirror using adaptive optics. This paper will also discuss how we can use a MEMS deformable mirror to improve the performance of the NPS segmented mirror telescope. The high-stroke, high-order actuated MEMS deformable mirror will correct the residual alignment and surface errors that are not corrected by the actuators on the mirrors. The mirror will use electrostatic actuation to eliminate the need for power to hold its position and will be capable of open-loop, go-to positioning.

  10. LOXT mirror design study

    NASA Technical Reports Server (NTRS)

    Vanspeybroeck, L.; Antrim, W.; Boyd, D.; Giacconi, R.; Sinnamon, G.; Stille, F.

    1972-01-01

    The final report for the large orbiting X-ray telescope (LOXT) high resolution mirror design study is presented. The following tasks were performed: (1) Generation of a reference and alternate preliminary design for the LOXT high resolution mirror assembly, which will meet the LOXT scientific requirements, and are within the present state of the art of materials and fabrication techniques. (2) Measurement, in X-rays, of the scattering properties of a variety of optical flats, embodying materials, coatings, and polishing techniques which might be applicable to the flight configuration LOXT high resolution mirror. (3) Preparation of a procurement specification for a paraboloid test mirror of the size of the innermost paraboloid of the high resolution mirror assembly, including the design requirements for the reference design evolved from this preliminary design study. The results of the engineering and scientific analysis and the conclusions drawn are presented. The procurement specification for the test mirror is included.

  11. Erected mirror optical switch

    DOEpatents

    Allen, James J.

    2005-06-07

    A microelectromechanical (MEM) optical switching apparatus is disclosed that is based on an erectable mirror which is formed on a rotatable stage using surface micromachining. An electrostatic actuator is also formed on the substrate to rotate the stage and mirror with a high angular precision. The mirror can be erected manually after fabrication of the device and used to redirect an incident light beam at an arbitrary angel and to maintain this state in the absence of any applied electrical power. A 1.times.N optical switch can be formed using a single rotatable mirror. In some embodiments of the present invention, a plurality of rotatable mirrors can be configured so that the stages and mirrors rotate in unison when driven by a single micromotor thereby forming a 2.times.2 optical switch which can be used to switch a pair of incident light beams, or as a building block to form a higher-order optical switch.

  12. Mesmerising mirror neurons.

    PubMed

    Heyes, Cecilia

    2010-06-01

    Mirror neurons have been hailed as the key to understanding social cognition. I argue that three currents of thought-relating to evolution, atomism and telepathy-have magnified the perceived importance of mirror neurons. When they are understood to be a product of associative learning, rather than an adaptation for social cognition, mirror neurons are no longer mesmerising, but they continue to raise important questions about both the psychology of science and the neural bases of social cognition. PMID:20167276

  13. Dynamic focus-tracking MEMS scanning micromirror with low actuation voltages for endoscopic imaging

    PubMed Central

    Strathman, Matthew; Liu, Yunbo; Li, Xingde; Lin, Lih Y.

    2013-01-01

    We demonstrate a 3-D scanning micromirror device that combines 2-D beam scanning with focus control in the same device using micro-electro-mechanical-systems (MEMS) technology. 2-D beam scanning is achieved with a biaxial gimbal structure and focus control is obtained with a deformable mirror membrane surface. The micromirror with 800 micrometer diameter is designed to be sufficiently compact and efficient so that it can be incorporated into an endoscopic imaging probe in the future. The design, fabrication and characterization of the device are described in this paper. Using the focus-tracking MEMS scanning mirror, we achieved an optical scanning range of >16 degrees with <40 V actuation voltage at resonance and a tunable focal length between infinity and 25 mm with <100V applied bias. PMID:24104304

  14. Dynamic focus-tracking MEMS scanning micromirror with low actuation voltages for endoscopic imaging.

    PubMed

    Strathman, Matthew; Liu, Yunbo; Li, Xingde; Lin, Lih Y

    2013-10-01

    We demonstrate a 3-D scanning micromirror device that combines 2-D beam scanning with focus control in the same device using micro-electro-mechanical-systems (MEMS) technology. 2-D beam scanning is achieved with a biaxial gimbal structure and focus control is obtained with a deformable mirror membrane surface. The micromirror with 800 micrometer diameter is designed to be sufficiently compact and efficient so that it can be incorporated into an endoscopic imaging probe in the future. The design, fabrication and characterization of the device are described in this paper. Using the focus-tracking MEMS scanning mirror, we achieved an optical scanning range of >16 degrees with <40 V actuation voltage at resonance and a tunable focal length between infinity and 25 mm with <100V applied bias. PMID:24104304

  15. Nanoscale Deformable Optics

    NASA Technical Reports Server (NTRS)

    Strauss, Karl F.; Sheldon, Douglas J.

    2011-01-01

    Several missions and instruments in the conceptual design phase rely on the technique of interferometry to create detectable fringe patterns. The intimate emplacement of reflective material upon electron device cells based upon chalcogenide material technology permits high-speed, predictable deformation of the reflective surface to a subnanometer or finer resolution with a very high degree of accuracy. In this innovation, a layer of reflective material is deposited upon a wafer containing (perhaps in the millions) chalcogenic memory cells with the reflective material becoming the front surface of a mirror and the chalcogenic material becoming a means of selectively deforming the mirror by the application of heat to the chalcogenic material. By doing so, the mirror surface can deform anywhere from nil to nanometers in spots the size of a modern day memory cell, thereby permitting realtime tuning of mirror focus and reflectivity to mitigate aberrations caused elsewhere in the optical system. Modern foundry methods permit the design and manufacture of individual memory cells having an area of or equal to the Feature (F) size of the design (assume 65 nm). Fabrication rules and restraints generally require the instantiation of one memory cell to another no closer than 1.5 F, or, for this innovation, 90 nm from its neighbor in any direction. Chalcogenide is a semiconducting glass compound consisting of a combination of chalcogen ions, the ratios of which vary according to properties desired. It has been shown that the application of heat to cells of chalcogenic material cause a large alteration in resistance to the range of 4 orders of magnitude. It is this effect upon which chalcogenidebased commercial memories rely. Upon removal of the heat source, the chalcogenide rapidly cools and remains frozen in the excited state. It has also been shown that the chalcogenide expands in volume because of the applied heat, meaning that the coefficient of expansion of chalcogenic

  16. Optical Performance Modeling of FUSE Telescope Mirror

    NASA Technical Reports Server (NTRS)

    Saha, Timo T.; Ohl, Raymond G.; Friedman, Scott D.; Moos, H. Warren

    2000-01-01

    We describe the Metrology Data Processor (METDAT), the Optical Surface Analysis Code (OSAC), and their application to the image evaluation of the Far Ultraviolet Spectroscopic Explorer (FUSE) mirrors. The FUSE instrument - designed and developed by the Johns Hopkins University and launched in June 1999 is an astrophysics satellite which provides high resolution spectra (lambda/Delta(lambda) = 20,000 - 25,000) in the wavelength region from 90.5 to 118.7 nm The FUSE instrument is comprised of four co-aligned, normal incidence, off-axis parabolic mirrors, four Rowland circle spectrograph channels with holographic gratings, and delay line microchannel plate detectors. The OSAC code provides a comprehensive analysis of optical system performance, including the effects of optical surface misalignments, low spatial frequency deformations described by discrete polynomial terms, mid- and high-spatial frequency deformations (surface roughness), and diffraction due to the finite size of the aperture. Both normal incidence (traditionally infrared, visible, and near ultraviolet mirror systems) and grazing incidence (x-ray mirror systems) systems can be analyzed. The code also properly accounts for reflectance losses on the mirror surfaces. Low frequency surface errors are described in OSAC by using Zernike polynomials for normal incidence mirrors and Legendre-Fourier polynomials for grazing incidence mirrors. The scatter analysis of the mirror is based on scalar scatter theory. The program accepts simple autocovariance (ACV) function models or power spectral density (PSD) models derived from mirror surface metrology data as input to the scatter calculation. The end product of the program is a user-defined pixel array containing the system Point Spread Function (PSF). The METDAT routine is used in conjunction with the OSAC program. This code reads in laboratory metrology data in a normalized format. The code then fits the data using Zernike polynomials for normal incidence

  17. Castable Amorphous Metal Mirrors and Mirror Assemblies

    NASA Technical Reports Server (NTRS)

    Hofmann, Douglas C.; Davis, Gregory L.; Agnes, Gregory S.; Shapiro, Andrew A.

    2013-01-01

    A revolutionary way to produce a mirror and mirror assembly is to cast the entire part at once from a metal alloy that combines all of the desired features into the final part: optical smoothness, curvature, flexures, tabs, isogrids, low CTE, and toughness. In this work, it has been demonstrated that castable mirrors are possible using bulk metallic glasses (BMGs, also called amorphous metals) and BMG matrix composites (BMGMCs). These novel alloys have all of the desired mechanical and thermal properties to fabricate an entire mirror assembly without machining, bonding, brazing, welding, or epoxy. BMGs are multi-component metal alloys that have been cooled in such a manner as to avoid crystallization leading to an amorphous (non-crystalline) microstructure. This lack of crystal structure and the fact that these alloys are glasses, leads to a wide assortment of mechanical and thermal properties that are unlike those observed in crystalline metals. Among these are high yield strength, carbide-like hardness, low melting temperatures (making them castable like aluminum), a thermoplastic processing region (for improving smoothness), low stiffness, high strength-to-weight ratios, relatively low CTE, density similar to titanium alloys, high elasticity and ultra-smooth cast parts (as low as 0.2-nm surface roughness has been demonstrated in cast BMGs). BMGMCs are composite alloys that consist of a BMG matrix with crystalline dendrites embedded throughout. BMGMCs are used to overcome the typically brittle failure observed in monolithic BMGs by adding a soft phase that arrests the formation of cracks in the BMG matrix. In some cases, BMGMCs offer superior castability, toughness, and fatigue resistance, if not as good a surface finish as BMGs. This work has demonstrated that BMGs and BMGMCs can be cast into prototype mirrors and mirror assemblies without difficulty.

  18. System Estimates Radius of Curvature of a Segmented Mirror

    NASA Technical Reports Server (NTRS)

    Rakoczy, John

    2008-01-01

    A system that estimates the global radius of curvature (GRoC) of a segmented telescope mirror has been developed for use as one of the subsystems of a larger system that exerts precise control over the displacements of the mirror segments. This GRoC-estimating system, when integrated into the overall control system along with a mirror-segment- actuation subsystem and edge sensors (sensors that measure displacements at selected points on the edges of the segments), makes it possible to control the GROC mirror-deformation mode, to which mode contemporary edge sensors are insufficiently sensitive. This system thus makes it possible to control the GRoC of the mirror with sufficient precision to obtain the best possible image quality and/or to impose a required wavefront correction on incoming or outgoing light. In its mathematical aspect, the system utilizes all the information available from the edge-sensor subsystem in a unique manner that yields estimates of all the states of the segmented mirror. The system does this by exploiting a special set of mirror boundary conditions and mirror influence functions in such a way as to sense displacements in degrees of freedom that would otherwise be unobservable by means of an edge-sensor subsystem, all without need to augment the edge-sensor system with additional metrological hardware. Moreover, the accuracy of the estimates increases with the number of mirror segments.

  19. Stable mirror mount

    DOEpatents

    Cutburth, Ronald W.

    1990-01-01

    An improved mirror mount assembly is disclosed. The mirror mount assembly provides a post assembly slidable in a Y-axis orientation and a nut plate assembly slidable in an X-axis orientation and a device for simultaneously locking the post assembly and the key assembly in a fixed position.

  20. Stable mirror mount

    DOEpatents

    Cutburth, R.W.

    1983-11-04

    An improved mirror mount assembly is disclosed. The mirror mount assembly provides a post assembly slidable in a Y-axis orientation and a nut plate assembly slidable in an X-axis orientation and means for simultaneously locking said post assembly and said key assembly in a fixed position.

  1. Bronze rainbow hologram mirrors

    NASA Astrophysics Data System (ADS)

    Dawson, P.

    2006-02-01

    This project draws on holographic embossing techniques, ancient artistic conventions of bronze mirror design and modelling and casting processes to accomplish portraiture of reflection. Laser scanning, 3D computer graphics and holographic imaging are employed to enable a permanent 3D static holographic image to appear integrated with the real-time moving reflection of a viewer's face in a polished bronze disc. The disc and the figure which holds it (caryatid) are cast in bronze from a lost wax model, a technique which has been used for millennia to make personal mirrors. The Caryatid form of bronze mirror which went through many permutations in ancient Egyptian, Greece and Rome shows a plethora of expressive figure poses ranging from sleek nudes to highly embellished multifigure arrangements. The prototype of this series was made for Australian choreographer Graeme Murphy, Artistic Director of the Sydney Dance Company. Each subsequent mirror will be unique in figure and holographic imagery as arranged between artist and subject. Conceptually this project references both the modern experience of viewing mirrors retrieved from ancient tombs, which due to deterioration of the surface no longer reflect, and the functioning of Chinese Magic mirrors, which have the ability to project a predetermined image. Inspired by the metaphorical potential of these mirrors, which do not reflect the immediate reality of the viewer, this bronze hologram mirror series enables each viewer to reflect upon himself or herself observing simultaneously the holographic image and their own partially obliterated reflection.

  2. The secondary mirror concept for the European Extremely Large Telescope

    NASA Astrophysics Data System (ADS)

    Mueller, Michael; Cayrel, Marc; Bonnet, Henri; Ciattaglia, Emanuela; Esselborn, Michael; Koch, Franz; Kurlandczyk, Herve; Pettazzi, Lorenzo; Rakich, Andrew; Sedghi, Babak

    2014-07-01

    The E-ELT is an active and adaptive 39-m telescope, with an anastigmat optical solution (5 mirrors including two flats), currently being developed by the European Southern Observatory (ESO). The convex 4-metre-class secondary mirror (M2) is a thin Zerodur meniscus passively supported by an 18 point axial whiffletree. A warping harness system allows to correct low order deformations of the M2 Mirror. Laterally the mirror is supported on 12 points along the periphery by pneumatic jacks. Due to its high optical sensitivity and the telescope gravity deflections, the M2 unit needs to allow repositioning the mirror during observation. Considering its exposed position 30m above the primary, the M2 unit has to provide good wind rejection. The M2 concept is described and major performance characteristics are presented.

  3. Tandem mirror plasma confinement apparatus

    DOEpatents

    Fowler, T. Kenneth

    1978-11-14

    Apparatus and method for confining a plasma in a center mirror cell by use of two end mirror cells as positively charged end stoppers to minimize leakage of positive particles from the ends of the center mirror cell.

  4. Space Mirror Alignment System

    NASA Technical Reports Server (NTRS)

    Jau, Bruno M.; McKinney, Colin; Smythe, Robert F.; Palmer, Dean L.

    2011-01-01

    An optical alignment mirror mechanism (AMM) has been developed with angular positioning accuracy of +/-0.2 arcsec. This requires the mirror s linear positioning actuators to have positioning resolutions of +/-112 nm to enable the mirror to meet the angular tip/tilt accuracy requirement. Demonstrated capabilities are 0.1 arc-sec angular mirror positioning accuracy, which translates into linear positioning resolutions at the actuator of 50 nm. The mechanism consists of a structure with sets of cross-directional flexures that enable the mirror s tip and tilt motion, a mirror with its kinematic mount, and two linear actuators. An actuator comprises a brushless DC motor, a linear ball screw, and a piezoelectric brake that holds the mirror s position while the unit is unpowered. An interferometric linear position sensor senses the actuator s position. The AMMs were developed for an Astrometric Beam Combiner (ABC) optical bench, which is part of an interferometer development. Custom electronics were also developed to accommodate the presence of multiple AMMs within the ABC and provide a compact, all-in-one solution to power and control the AMMs.

  5. Mirror plasma apparatus

    DOEpatents

    Moir, Ralph W.

    1981-01-01

    A mirror plasma apparatus which utilizes shielding by arc discharge to form a blanket plasma and lithium walls to reduce neutron damage to the wall of the apparatus. An embodiment involves a rotating liquid lithium blanket for a tandem mirror plasma apparatus wherein the first wall of the central mirror cell is made of liquid lithium which is spun with angular velocity great enough to keep the liquid lithium against the first material wall, a blanket plasma preventing the lithium vapor from contaminating the plasma.

  6. NIF small mirror mount

    SciTech Connect

    McCarville, T

    1999-07-01

    A number of small mirror mounts have been identified that meet the stringent stability, wave front, and cleanliness standards of the NIF. These requirements are similar to those required in other performance critical optical design applications. Future design teams would conserve time and effort if recognized standards were established for mirror mount design and performance characteristics. Standards for stability, physical features, wave front distortion, and cleanliness would simplify the qualification process considerably. At this point such standards are not difficult to define, as the technical support work has been performed repeatedly by mirror mount consumers and suppliers.

  7. Design, fabrication and testing of active carbon shell mirrors for space telescope applications

    NASA Astrophysics Data System (ADS)

    Steeves, John; Laslandes, Marie; Pellegrino, Sergio; Redding, David; Bradford, Samuel Case; Wallace, James Kent; Barbee, Troy

    2014-07-01

    A novel active mirror concept based on carbon fiber reinforced polymer (CFRP) materials is presented. A nanolaminate facesheet, active piezoelectric layer and printed electronics are implemented in order to provide the reflective surface, actuation capabilities and electrical wiring for the mirror. Mirrors of this design are extremely thin (500-850 µm), lightweight (~ 2 kg/m2) and have large actuation capabilities (~ 100 µm peak- to-valley deformation per channel). Replication techniques along with simple bonding/transferring processes are implemented eliminating the need for grinding and polishing steps. An outline of the overall design, component materials and fabrication processes is presented. A method to size the active layer for a given mirror design, along with simulation predictions on the correction capabilities of the mirror are also outlined. A custom metrology system used to capture the highly deformable nature of the mirrors is demonstrated along with preliminary prototype measurements.

  8. The adaptive secondary mirror for the 6.5 conversion of the Multiple Mirror Telescope

    NASA Astrophysics Data System (ADS)

    Riccardi, Armando; Brusa, Guido; Del Vecchio, Ciro; Baisi, Roberto; Andrighettoni, M.; Gallieni, Daneile; Zocchi, F.; Lloyd-Hart, Michael; Martin, Hubert M.; Wildi, François

    We present the laboratory results performed by the non-conventional secondary mirror that will be used as corrector for the adaptive optics system of the 6.5m conversion of MMT. The design of the unit consists of a 2mm-thick 642mm-diameter convex deformable mirror whose figure is controlled by 336 electro-magnetic force actuators, a thick shell used as position reference and an aluminum shell as actuator support and cooling. The actuator forces are controlled using feed-forward and de-centralized closed loop compensation thanks to the 40kHz feedback signals from the 336 capacitive position sensors. The digital real-time control and the unit monitoring is obtained using custom-made on-board electronics based on 168 DSPs. This paper will report on extensive static and dynamical measurements aimed at characterize the mirror response function, that shows a proper atmospheric turbulence compensation.

  9. Development of GMT fast steering secondary mirror assembly

    NASA Astrophysics Data System (ADS)

    Cho, Myung; Corredor, Andrew; Dribusch, Christoph; Park, Won Hyun; Muller, Gary; Johns, Matt; Hull, Charlie; Kern, Jonathan; Kim, Young-Soo

    2014-07-01

    The Giant Magellan Telescope (GMT) is one of Extremely large telescopes, which is 25m in diameter featured with two Gregorian secondary mirrors, an adaptive secondary mirror (ASM) and a fast-steering secondary mirror (FSM). The FSM is 3.2 m in diameter and built as seven 1.1 m diameter circular segments conjugated 1:1 to the seven 8.4m segments of the primary. The guiding philosophy in the design of the FSM segment mirror is to minimize development and fabrication risks ensuring a set of secondary mirrors are available on schedule for telescope commissioning and early operations in a seeing limited mode. Each FSM segment contains a tip-tilt capability for fine co-alignment of the telescope subapertures and fast guiding to attenuate telescope wind shake and mount control jitter, thus optimizing the seeing limited performance of the telescope. The final design of the FSM mirror and support system configuration was optimized using finite element analyses and optical performance analyses. The optical surface deformations, image qualities, and structure functions for the gravity print-through cases, thermal gradient effects, and dynamic performances were evaluated. The results indicated that the GMT FSM mirror and its support system will favorably meet the optical performance goals for residual surface error and the FSM surface figure accuracy requirement defined by encircled energy (EE80) in the focal plane. The mirror cell assembly analysis indicated an excellent dynamic stiffness which will support the goal of tip-tilt operation.

  10. Composite Material Mirror Testing

    NASA Technical Reports Server (NTRS)

    2000-01-01

    In this photograph, the composite material mirror is tested in the X-Ray Calibration Facility at the Marshall Space Flight Center for the James Webb Space Telescope (JWST). The mirror test conducted was to check the ability to accurately model and predict the cryogenic performance of complex mirror systems, and the characterization of cryogenic dampening properties of beryllium. The JWST, a next generation successor to the Hubble Space Telescope (HST), was named in honor of James W. Webb, NASA's second administrator, who led NASA in the early days of the fledgling Aerospace Agency. Scheduled for launch in 2010 aboard an expendable launch vehicle, the JWST will be able to look deeper into the universe than the HST because of the increased light-collecting power of its larger mirror and the extraordinary sensitivity of its instrument to infrared light.

  11. JWST Mirror Installation

    NASA Video Gallery

    The first six of 18 hexagonal shaped segments that will form NASA’s James Webb Space Telescope’s primary mirror for space observations were readied this week to begin final cryogenic testing at...

  12. The Athena Mirror

    NASA Astrophysics Data System (ADS)

    Wille, Eric

    2016-07-01

    The Athena mission (Advanced Telescope for High Energy Astrophysics) requires lightweight X-ray Wolter optics with a high angular resolution and large effective area. For achieving an effective area of 2 m^2 (at 1 keV) and an angular resolution of below 5 arcsec, the Silicon Pore Optics technology was developed by ESA together with a consortium of European industry. Silicon Pore Optics are made of commercial Si wafers using process technology adapted from the semiconductor industry. We present the current design of the Athena mirror concentrating on the technology development status of the Silicon Pore Optics, ranging from the manufacturing of single mirror plates towards complete focusing mirror modules and their integration into the mirror structure.

  13. The Rotating Mirror.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1981-01-01

    Discusses theory of the rotating mirror, its use in measuring the velocity of the electrical signal in wires, and the velocity of light. Concludes with a description of the manometric flame apparatus developed for analyzing sound waves. (SK)

  14. Mirror Technology Roadmap

    NASA Technical Reports Server (NTRS)

    Stahl, H. Phil

    2006-01-01

    NASA's Mirror Technology Roadmap identifies specific capabilities requiring significant advances in optical fabrication and testing to enable the next generation of large-aperture space telescopes for astronomy and Earth science missions ranging from x-ray to infrared.

  15. The Development of a Dual-Warhead Impact System for Dynamic Linearity Measurement of a High-g Micro-Electro-Mechanical-Systems (MEMS) Accelerometer.

    PubMed

    Shi, Yunbo; Yang, Zhicai; Ma, Zongmin; Cao, Huiliang; Kou, Zhiwei; Zhi, Dan; Chen, Yanxiang; Feng, Hengzhen; Liu, Jun

    2016-01-01

    Despite its extreme significance, dynamic linearity measurement for high-g accelerometers has not been discussed experimentally in previous research. In this study, we developed a novel method using a dual-warhead Hopkinson bar to measure the dynamic linearity of a high-g acceleration sensor with a laser interference impact experiment. First, we theoretically determined that dynamic linearity is a performance indicator that can be used to assess the quality merits of high-g accelerometers and is the basis of the frequency response. We also found that the dynamic linearity of the dual-warhead Hopkinson bar without an accelerometer is 2.5% experimentally. Further, we verify that dynamic linearity of the accelerometer is 3.88% after calibrating the Hopkinson bar with the accelerometer. The results confirm the reliability and feasibility of measuring dynamic linearity for high-g accelerometers using this method. PMID:27338383

  16. The Development of a Dual-Warhead Impact System for Dynamic Linearity Measurement of a High-g Micro-Electro-Mechanical-Systems (MEMS) Accelerometer

    PubMed Central

    Shi, Yunbo; Yang, Zhicai; Ma, Zongmin; Cao, Huiliang; Kou, Zhiwei; Zhi, Dan; Chen, Yanxiang; Feng, Hengzhen; Liu, Jun

    2016-01-01

    Despite its extreme significance, dynamic linearity measurement for high-g accelerometers has not been discussed experimentally in previous research. In this study, we developed a novel method using a dual-warhead Hopkinson bar to measure the dynamic linearity of a high-g acceleration sensor with a laser interference impact experiment. First, we theoretically determined that dynamic linearity is a performance indicator that can be used to assess the quality merits of high-g accelerometers and is the basis of the frequency response. We also found that the dynamic linearity of the dual-warhead Hopkinson bar without an accelerometer is 2.5% experimentally. Further, we verify that dynamic linearity of the accelerometer is 3.88% after calibrating the Hopkinson bar with the accelerometer. The results confirm the reliability and feasibility of measuring dynamic linearity for high-g accelerometers using this method. PMID:27338383

  17. Towards a better mirror

    NASA Technical Reports Server (NTRS)

    Hoffer, David

    1987-01-01

    Telesat's Getaway Special competition was designed to promote interest in space among high school students in Canada. The winning entry proposed the manufacture of mirrors in microgravity and to compare the optical properties of these mirrors with similar ones made on Earth. Telesat engineers designed and built the experiment which flew on the Atlantic shuttle on November 27, 1985. This paper outlines the design evolution, its implementation, the manufacture and test of the GAS and the results of the experiment.

  18. Haglund's Deformity

    MedlinePlus

    ... Is Haglund’s Deformity? Haglund’s deformity is a bony enlargement on the back of the heel. The soft ... the Achilles tendon becomes irritated when the bony enlargement rubs against shoes. This often leads to painful ...

  19. Notes on moving mirrors

    SciTech Connect

    Obadia, N.; Parentani, R.

    2001-08-15

    The Davies-Fulling (DF) model describes the scattering of a massless field by a noninertial mirror in two dimensions. In this paper, we generalize this model in two different ways. First, we consider partially reflecting mirrors. We show that the Bogoliubov coefficients relating inertial modes can be expressed in terms of the reflection factor and the transformation from inertial modes to modes at rest with respect to the mirror. In this perspective, the DF model is simply the limiting case when the reflection factor is unity for all frequencies. In the second part, we introduce an alternative model which is based on self-interactions described by an action principle. When the coupling is constant, this model can be solved exactly and gives rise to a partially reflecting mirror. The usefulness of this dynamical model lies in the possibility of switching off the coupling between the mirror and field. This allows us to obtain regularized expressions for the fluxes in situations where they are singular when using the DF model. Two examples are considered. The first concerns the flux induced by the disappearance of the reflection condition, a situation which bears some analogies with the end of the evaporation of a black hole. The second case concerns the flux emitted by a uniformly accelerated mirror.

  20. Madelung Deformity.

    PubMed

    Kozin, Scott H; Zlotolow, Dan A

    2015-10-01

    Madelung deformity of the wrist is more common in females and is often associated with Leri Weill dyschondrosteosis, a mesomelic form of dwarfism. Patients with Madelung deformity often report wrist deformity resulting from the prominence of the relatively long ulna. The typical Madelung deformity is associated with a Vickers ligament that creates a tether across the volar-ulnar radial physis that restricts growth across this segment. The distal radius deforms in the coronal (increasing radial inclination) and the sagittal (increasing volar tilt) planes. There is lunate subsidence and the proximal carpal row adapts to the deformity by forming an upside-down pyramid shape or triangle. Treatment depends on the age at presentation, degree of deformity, and magnitude of symptoms. Mild asymptomatic deformity warrants a period of nonsurgical management with serial x-ray examinations because the natural history is unpredictable. Many patients never require surgical intervention. Progressive deformity in the young child with considerable growth potential remaining requires release of Vickers ligament and radial physiolysis to prevent ongoing deterioration Concomitant ulnar epiphysiodesis may be necessary. Advanced asymptomatic deformity in older children with an unacceptable-appearing wrist or symptomatic deformity are indications for surgery. A dome osteotomy of the radius allows 3-dimensional correction of the deformity. Positive radiographic and clinical results after dome osteotomy have been reported. PMID:26341718

  1. Freeform mirror based optical systems for FAME

    NASA Astrophysics Data System (ADS)

    Agócs, Tibor; Kroes, Gabby; Venema, Lars; Hugot, Emmanuel; Schnetler, Hermine; Jaskó, Attila

    2014-07-01

    In this paper we present the design of freeform mirror based optical systems that have the potential to be used in future astronomical instrumentation in the era of extremely large ground based telescopes. Firstly we describe the optical requirements followed by a summary of the optimization methodology used to design the freeform surface. The intention is to create optical architectures, which not only have the numerous advantages of freeform based systems (increased optical performance and/or reduction of mass and volume), but also can be manufactured and tested with today's manufacturing techniques and technologies. The team plans to build a demonstrator based on one of the optical design examples presented in this paper. The demonstrator will be built and tested as part of the OPTICON FP7 Freeform Active Mirror Experiment (FAME) project. A hydroforming technique developed as part of the previous OPTICON FP7 project will be used to produce an accurate, compact and stable freeform mirror. The manufacturing issues normally experienced in the production of freeform mirrors are solved through the hydroforming of thin polished substrates, which then will be supported with an active array structure. The active array will be used to compensate for residual manufacturing errors, thermo-elastic deformation and gravity-induced errors.

  2. Study on 400-1500nm reflecting coatings on lightweight mirrors

    NASA Astrophysics Data System (ADS)

    Zhang, Yao-ping; Xu, Hong

    2007-12-01

    Image-stabilization systems are widely used during astronomical image integration because of their large gain of image quality and relatively simple control system. Probably the simplest system is the one that tilts a mirror to correct angular variations caused by atmospheric fluctuations, vibration tilt of the telescope, or angular errors of internal components. Lightweight (structured) mirrors based on piezoelectric actuators are of important part of these systems. The coating of lightweight (structured) mirrors and the associated support systems involves the prediction of the magnitude and nature of the elastic deformation of mirror surface due to mechanical and thermal residual stress during coating. The clamping ways are firstly analyzed in this paper, and the finite element method of structural analysis makes it possible to include conveniently the deformation and stress of a lightweight mirror in consideration of effects of thermal gradients and mechanical loads during coating. Two models with different clamping ways are set up by using FEA soft. The distribution of deformation and stress of lightweight mirror caused by thermal residual stress is analyzed. The coated lightweight mirror is measured by interferometer and the result shows the calculated and measured results have good compatibility. Based on the results of these studies, we select a better clamping way to coating the lightweight mirror. The lightweight mirror for astronomical telescope intensified with silver has good optical properties, but the silver mirror has the faults of weak adhesion to glass substrate and the mirror is easily corroded by atmospheric pollution. In order to solve this problem, several silver adhesion layers are studied. Due to mutual action of Al2O3 and silver film, the developed Al2O3-based silver intensified mirror has overcome the above faults and achieved good effect. Finally, the coating is measured by making use of spectrometer. The average reflectance of coating is

  3. Measuring deformations with deflectometry

    NASA Astrophysics Data System (ADS)

    Li, Wansong; Huke, Philipp; Burke, Jan; von Kopylow, Christoph; Bergmann, Ralf B.

    2014-07-01

    Phase-measuring deflectometry is a powerful method to measure reflective surfaces. It is relatively easy to extract slope and curvature information from the measured phase maps; however, retrieving shape information depends very sensitively on the calibration of the camera and the geometry of the measurement system. Whereas we have previously demonstrated shape uncertainties below 1 μm, the range below 100 nm is currently inaccessible to deflectometric shape measurement. On the other hand, the astounding sensitivity of deflectometry can be put to good use for deformation measurements. The evaluation of corresponding shape differences rather than absolute shapes is much less susceptible to system calibration errors and its resolution is given mostly by the measurement system's sensitivity. We give an overview of recent progress in difference deflectometry. Firstly we show results from solar mirror substrates under load to detect flaws with high sensitivity. Secondly we present a preliminary simulation study of achievable deformation-measurement uncertainties to assess the feasibility of deflectometric characterisation of actuator performance and gravity sag for the mirror segments of the European Extremely Large Telescope (E-ELT). Results for the relevant Zernike terms show reliable detection of Zernike coefficients at the 25 nm level. Random artefacts related to noise in the phase measurements are seen to translate into bogus Zernike terms, and we discuss possible mitigation techniques to enhance the sensitivity and accuracy further.

  4. Kinematic Evaluation of the Whiffletree Lateral Support Setup and its Application for the Mirror Support of the TMT Tertiary Mirror

    NASA Astrophysics Data System (ADS)

    Fu-guo, W.; Linmin, Z.; Jin, X.

    2015-05-01

    With increasing size of the reflecting mirror apertures in telescopes, the lateral support is becoming more and more important. In order to find a setup satisfying the requirements for the TMT tertiary mirror, based on the classic three-point flexure support setup, a twelve-point lateral support setup was investigated its basic internal relations and properties were investigated. The virtual equivalent circle concept is then proposed to evaluate different potential setups. By studying the relationship between the virtual equivalent circle radius and the thermal deformation and resonant frequency, it can be concluded that a larger virtual equivalent circle radius results in a smaller the thermal deformation and a higher resonant frequency. Preliminary research results suggested that the TMT tertiary mirror surface figure error and thermal deformation requirements can easily be met. However, it was more difficult to obtain resonant frequencies higher than 15 Hz. Based on the virtual equivalent circle concept, the TMT tertiary mirror support setup was optimized, resulting in a resonant frequency of 17.7 Hz, which satisfies the requirements. The whiffletree lateral support setup can be applied to similar reflecting mirror support structures.

  5. Lightweight Deployable Mirrors with Tensegrity Supports

    NASA Technical Reports Server (NTRS)

    Zeiders, Glenn W.; Bradford, Larry J.; Cleve, Richard C.

    2004-01-01

    first-order rotation between the uppermost and lowermost planes is zero. The need to have zero net rotation between these planes under all loading conditions in a typical practical structure is what prompts the use of the mirror configuration. Force and moment loadings other than simple axial compression produce only second-order deformations through strains in the struts and cables.

  6. Actuated Hybrid Mirror Telescope

    NASA Technical Reports Server (NTRS)

    Hickey, Gregory; Redding, David; Lowman, Andrew; Cohen, David; Ohara, Catherine

    2005-01-01

    The figure depicts the planned Actuated Hybrid Mirror Telescope (AHMT), which is intended to demonstrate a new approach to the design and construction of wide-aperture spaceborne telescopes for astronomy and Earth science. This technology is also appropriate for Earth-based telescopes. The new approach can be broadly summarized as using advanced lightweight mirrors that can be manufactured rapidly at relatively low cost. More specifically, it is planned to use precise replicated metallic nanolaminate mirrors to obtain the required high-quality optical finishes. Lightweight, dimensionally stable silicon carbide (SiC) structures will support the nanolaminate mirrors in the required surface figures. To enable diffraction- limited telescope performance, errors in surface figures will be corrected by use of mirror-shape-control actuators that will be energized, as needed, by a wave-front-sensing and control system. The concepts of nanolaminate materials and mirrors made from nanolaminate materials were discussed in several previous NASA Tech Briefs articles. Nanolaminates constitute a relatively new class of materials that can approach theoretical limits of stiffness and strength. Nanolaminate mirrors are synthesized by magnetron sputter deposition of metallic alloys and/or compounds on optically precise master surfaces to obtain optical-quality reflector surfaces backed by thin shell structures. As an integral part of the deposition process, a layer of gold that will constitute the reflective surface layer is deposited first, eliminating the need for a subsequent and separate reflective-coating process. The crystallographic textures of the nanolaminate will be controlled to optimize the performance of the mirror. The entire deposition process for making a nanolaminate mirror takes less than 100 hours, regardless of the mirror diameter. Each nanolaminate mirror will be bonded to its lightweight SiC supporting structure. The lightweight nanolaminate mirrors and Si

  7. Helically linked mirror arrangement

    SciTech Connect

    Ranjan, P.

    1986-08-01

    A scheme is described for helical linking of mirror sections, which endeavors to combine the better features of toroidal and mirror devices by eliminating the longitudinal loss of mirror machines, having moderately high average ..beta.. and steady state operation. This scheme is aimed at a device, with closed magnetic surfaces having rotational transform for equilibrium, one or more axisymmetric straight sections for reduced radial loss, a simple geometrical axis for the links and an overall positive magnetic well depth for stability. We start by describing several other attempts at linking of mirror sections, made both in the past and the present. Then a description of our helically linked mirror scheme is given. This example has three identical straight sections connected by three sections having helical geometric axes. A theoretical analysis of the magnetic field and single-particle orbits in them leads to the conclusion that most of the passing particles would be confined in the device and they would have orbits independent of pitch angle under certain conditions. Numerical results are presented, which agree well with the theoretical results as far as passing particle orbits are concerned.

  8. Physics of mirror systems

    SciTech Connect

    Post, R.F.

    1982-05-01

    In recent years the emphasis in research on the magnetic mirror approach to fusion has been shifted to address what are essentially economically-motivated issues. The introduction of the Tandem Mirror idea solved in principal the problem of low Q (low fusion power gain) of mirror-based fusion systems. In order to optimize the tandem mirror idea from an economic standpoint, some important improvements have been suggested. These improvements include the thermal barrier idea of Baldwin and Logan and the axicell concept of Kesner. These new modifications introduce some special physics considerations. Among these are (1) The MHD stability properties of high energy electron components in the end cells; (2) The optimization of end-cell magnetic field configurations with the objective of minimizing equilibrium parallel currents; (3) The suppression of microstabilities by use of sloshing ion distributions. Following a brief outline of tandem mirror concepts, the above three topics are discussed, with illustrative examples taken from earlier work or from recent design studies.

  9. Innovative Magnetic Mirror Concepts

    NASA Astrophysics Data System (ADS)

    Simonen, Thomas

    2009-11-01

    In the past two decades, while magnetic mirror research in the US was curtailed, several innovations have been proposed and many have been demonstrated in Japan and Russia in the Gamma 10 and GDT experiments. These advances have led to new scientific understanding, means of overcoming previous short comings, and reconsideration of magnetic mirror systems as a modest size material testing neutron source or as a fusion- fission hybrid system. Compared to toroidal systems, the linear geometry of mirror systems has the significant advantages of easing construction, operation and maintenance, but has a less developed data base. The recent innovations include reliance on axi-symmetric mirror coils, suppression of energetic-ion cyclotron-modes with potential confined warm plasma, and sheared ExB flow stabilization of drift waves. To enable increased electron temperature, the magnetic field expansion ratio from the mirror to the end wall is increased beyond the square root of the ion to electron mass ratio. This expansion inhibits electron thermal conduction, reduces the incident wall power flux to low levels, and isolates plasma-wall interactions far from the confined plasma.

  10. Influence functions of a thin shallow meniscus-shaped mirror.

    PubMed

    Arnold, L

    1997-04-01

    Thin shallow spherical shell theory is used to derive the general influence function, owing to uniform and/or discrete (actuators) loads, for a thin shallow meniscus-shaped mirror of uniform thickness with a central hole and supported at discrete points. Small elastic deformations are considered. No symmetry on the load distribution constrains the model. Explicit analytical expressions of the set of equations are given for calculating the influence functions. Results agree with the finite element analysis (FEA) to within 1%. When the FEA requires megabytes of RAM memory, the analytical method needs only kilobytes and typically runs 30 times faster. This is a crucial advantage for the iterative optimization of mirror supports such as large passive or active meniscus-shaped primary mirror supports or Cassegrain/Gregorian adaptive secondary actuator configurations. References are given on estimating the shear effects (thick mirror), the thickness variation effect, and the influence of the size of the support pads. PMID:18253168

  11. Primary adaptive mirrors for ELTs: a report on preliminary studies

    NASA Astrophysics Data System (ADS)

    Riccardi, Armando; Del Vecchio, Ciro; Salinari, Piero; Brusa, Guido; Lardiere, Olivier; Gallieni, Daniele; Biasi, Roberto; Mantegazza, Paolo

    2004-07-01

    At the moment the best bet to obtain an extremely high actuator density for extremely large pupils seems to be that of extending the current adaptive secondary mirror technology to segmented "adaptive primaries." The main components of a segment of an adaptive primary mirror are beng studied in order to determine all the parameters able to statically keep the mechanical response within the optical specifications and to dynamically provide the stiffness and damping features needed by the adaptive optics control system. Both static and dynamical requirements depend critically on actuator geometry and structure, mirror shape and thickness, and implementation of the control system. The mechanical response has been numerically evaluated in terms of deformation under gravity, mirror influence functions and actuator layout, including their interface to the shell.

  12. Cryogenic mirror analysis

    NASA Technical Reports Server (NTRS)

    Nagy, S.

    1988-01-01

    Due to extraordinary distances scanned by modern telescopes, optical surfaces in such telescopes must be manufactured to unimaginable standards of perfection of a few thousandths of a centimeter. The detection of imperfections of less than 1/20 of a wavelength of light, for application in the building of the mirror for the Space Infrared Telescope Facility, was undertaken. Because the mirror must be kept very cold while in space, another factor comes into effect: cryogenics. The process to test a specific morror under cryogenic conditions is described; including the follow-up analysis accomplished through computer work. To better illustrate the process and analysis, a Pyrex Hex-Core mirror is followed through the process from the laser interferometry in the lab, to computer analysis via a computer program called FRINGE. This analysis via FRINGE is detailed.

  13. Smart materials optical mirrors

    NASA Astrophysics Data System (ADS)

    Chen, Peter C.; Rabin, Douglas M.

    2014-08-01

    We report the fabrication of imaging quality optical mirrors with smooth surfaces using carbon nanotubes embedded in an epoxy matrix. CNT/epoxy is a multifunctional or `smart' composite material that has sensing capabilities and can be made to incorporate self-actuation as well. Moreover, since the precursor is a low density liquid, large and lightweight mirrors can be fabricated by processes such as replication, spincasting, and 3D printing. The technology therefore holds promise for development of a new generation of lightweight, compact `smart' telescope mirrors with figure sensing and active or adaptive figure control. We report on measurements made of optical and mechanical characteristics. We discuss possible paths for future development.

  14. Carbon nanotube optical mirrors

    NASA Astrophysics Data System (ADS)

    Chen, Peter C.; Rabin, Douglas

    2015-01-01

    We report the fabrication of imaging quality optical mirrors with smooth surfaces using carbon nanotubes (CNT) embedded in an epoxy matrix. CNT/epoxy is a multifunctional composite material that has sensing capabilities and can be made to incorporate self-actuation. Moreover, as the precursor is a low density liquid, large and lightweight mirrors can be fabricated by processes such as replication, spincasting, and three-dimensional printing. Therefore, the technology holds promise for the development of a new generation of lightweight, compact "smart" telescope mirrors with figure sensing and active or adaptive figure control. We report on measurements made of optical and mechanical characteristics, active optics experiments, and numerical modeling. We discuss possible paths for future development.

  15. Development of SiC Mirror for ASTRO-F

    NASA Astrophysics Data System (ADS)

    Kaneda, H.; Onaka, T.; Yamashiro, R.

    2000-12-01

    The development of the light-weight silicon carbide mirrors for the ASTRO-F mission is described in this paper. These mirrors are made of a sandwich-type SiC material, consisting of light porous core and dense CVD (chemical vapor deposition) coat of SiC. The primary mirror has a diameter of 710 mm and weighs only 11 kg. Combined with the secondary mirror of the same type, they form Ritchey-Chretien type telescope (F/6), which is cooled down to 5.8 K. Fabrication of the small-scale test SiC mirror has been successful which shows very little deformation of the figure at liquid-helium temperatures. Another type of the SiC coated mirror has been tested which has the same size as flight model, but of which core is made of graphite. At present, polishing of the flight-model primary mirror is going on. Construction of the flight model telescope system will be finished in 2001.

  16. Arithmetic properties of mirror map and quantum coupling

    NASA Astrophysics Data System (ADS)

    Lian, Bong H.; Yau, Shing-Tung

    1996-02-01

    We study some arithmetic properties of the mirror maps and the quantum Yukawa couplings for some 1-parameter deformations of Calabi-Yau manifolds. First we use the Schwarzian differential equation, which we derived previously, to characterize the mirror map in each case. For algebraic K3 surfaces, we solve the equation in terms of the J-function. By deriving explicit modular relations we prove that some K3 mirror maps are algebraic over the genus zero function field Q( J). This leads to a uniform proof that those mirror maps have integral Fourier coefficients. Regarding the maps as Riemann mappings, we prove that they are genus zero functions. By virtue of the Conway-Norton conjecture (proved by Borcherds using Frenkel-Lepowsky-Meurman's Moonshine module), we find that these maps are actually the reciprocals of the Thompson series for certain conjugacy classes in the Griess-Fischer group. This also gives, as an immediate consequence, a second proof that those mirror maps are integral. We thus conjecture a surprising connection between K3 mirror maps and the Thompson series. For threefolds, we construct a formal nonlinear ODE for the quantum coupling reduced mod p. Under the mirror hypothesis and an integrality assumption, we derive mod p congurences for the Fourier coefficients. For the quintics, we deduce, (at least for 5× d) that the degree d instanton numbers n d are divisible by 53 — a fact first conjectured by Clemens.

  17. Wavefront aberration measurements and corrections through thick tissue using fluorescent microsphere reference beacons

    PubMed Central

    Azucena, Oscar; Crest, Justin; Cao, Jian; Sullivan, William; Kner, Peter; Gavel, Donald; Dillon, Daren; Olivier, Scot; Kubby, Joel

    2010-01-01

    We present a new method to directly measure and correct the aberrations introduced when imaging through thick biological tissue. A Shack-Hartmann wavefront sensor is used to directly measure the wavefront error induced by a Drosophila embryo. The wavefront measurements are taken by seeding the embryo with fluorescent microspheres used as “artificial guide-stars.” The wavefront error is corrected in ten millisecond steps by applying the inverse to the wavefront error on a micro-electro-mechanical deformable mirror in the image path of the microscope. The results show that this new approach is capable of improving the Strehl ratio by 2 times on average and as high as 10 times when imaging through 100 μm of tissue. The results also show that the isoplanatic half-width is approximately 19 μm resulting in a corrected field of view 38 μm in diameter around the guide-star. PMID:20721137

  18. Progress with MEMS x-ray micro pore optics

    NASA Astrophysics Data System (ADS)

    Ezoe, Yuichiro; Moriyama, Teppei; Ogawa, Tomohiro; Kakiuchi, Takuya; Ohashi, Takaya; Mitsuishi, Ikuyuki; Mitsuda, Kazuhisa; Horade, Mitsuhiro; Sugiyama, Susumu; Riveros, Raul E.; Yamaguchi, Hitomi; Kanamori, Yoshiaki; Morishita, Kohei; Nakajima, Kazuo; Maeda, Ryutaro

    2012-09-01

    Our development of ultra light-weight X-ray micro pore optics based on MEMS (Micro Electro Mechanical System) technologies is described. Using dry etching or X-ray lithography and electroplating, curvilinear sidewalls through a flat wafer are fabricated. Sidewalls vertical to the wafer surface are smoothed by use of high temperature annealing and/or magnetic field assisted finishing to work as X-ray mirrors. The wafer is then deformed to a spherical shape. When two spherical wafers with different radii of curvature are stacked, the combined system will be an approximated Wolter type-I telescope. This method in principle allows high angular resolution and ultra light-weight X-ray micro pore optics. In this paper, performance of a single-stage optic, coating of a heavy metal on sidewalls with atomic layer deposition, and assembly of a Wolter type-I telescope are reported.

  19. Transition Metal Switchable Mirror

    SciTech Connect

    2009-01-01

    The switchable-mirrors technology was developed by Tom Richardson and Jonathan Slack of Berkeley Lab's Environmental Energy Technologies Division. By using transition metals rather than the rare earth metals used in the first metal-hydride switchable mirrors, Richardson and Slack were able to lower the cost and simplify the manufacturing process. Energy performance is improved as well, because the new windows can reflect or transmit both visible and infrared light. Besides windows for offices and homes, possible applications include automobile sunroofs, signs and displays, aircraft windows, and spacecraft. More information at: http://windows.lbl.gov/materials/chromogenics/default.htm

  20. Transition Metal Switchable Mirror

    ScienceCinema

    None

    2010-01-08

    The switchable-mirrors technology was developed by Tom Richardson and Jonathan Slack of Berkeley Lab's Environmental Energy Technologies Division. By using transition metals rather than the rare earth metals used in the first metal-hydride switchable mirrors, Richardson and Slack were able to lower the cost and simplify the manufacturing process. Energy performance is improved as well, because the new windows can reflect or transmit both visible and infrared light. Besides windows for offices and homes, possible applications include automobile sunroofs, signs and displays, aircraft windows, and spacecraft.

  1. Transition Metal Switchable Mirror

    ScienceCinema

    None

    2013-05-29

    The switchable-mirrors technology was developed by Tom Richardson and Jonathan Slack of Berkeley Lab's Environmental Energy Technologies Division. By using transition metals rather than the rare earth metals used in the first metal-hydride switchable mirrors, Richardson and Slack were able to lower the cost and simplify the manufacturing process. Energy performance is improved as well, because the new windows can reflect or transmit both visible and infrared light. Besides windows for offices and homes, possible applications include automobile sunroofs, signs and displays, aircraft windows, and spacecraft. More information at: http://windows.lbl.gov/materials/chromogenics/default.htm

  2. Mirror Measurement Device

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A Small Business Innovation Research (SBIR) contract led to a commercially available instrument used to measure the shape profile of mirror surfaces in scientific instruments. Bauer Associates, Inc.'s Bauer Model 200 Profilometer is based upon a different measurement concept. The local curvature of the mirror's surface is measured at many points, and the collection of data is computer processed to yield the desired shape profile. (Earlier profilometers are based on the principle of interferometry.) The system is accurate and immune to problems like vibration and turbulence. Two profilometers are currently marketed, and a third will soon be commercialized.

  3. Flat Focusing Mirror

    PubMed Central

    Cheng, Y. C.; Kicas, S.; Trull, J.; Peckus, M.; Cojocaru, C.; Vilaseca, R.; Drazdys, R.; Staliunas, K.

    2014-01-01

    The control of spatial propagation properties of narrow light beams such as divergence, focusing or imaging are main objectives in optics and photonics. In this letter, we propose and demonstrate experimentally a flat focusing mirror, based on an especially designed dielectric structure without any optical axis. More generally, it also enables imaging any light pattern in reflection. The flat focusing mirror with a transversal invariance can largely increase the applicability of structured photonic materials for light beam propagation control in small-dimension photonic circuits. PMID:25228358

  4. Flat focusing mirror.

    PubMed

    Cheng, Y C; Kicas, S; Trull, J; Peckus, M; Cojocaru, C; Vilaseca, R; Drazdys, R; Staliunas, K

    2014-01-01

    The control of spatial propagation properties of narrow light beams such as divergence, focusing or imaging are main objectives in optics and photonics. In this letter, we propose and demonstrate experimentally a flat focusing mirror, based on an especially designed dielectric structure without any optical axis. More generally, it also enables imaging any light pattern in reflection. The flat focusing mirror with a transversal invariance can largely increase the applicability of structured photonic materials for light beam propagation control in small-dimension photonic circuits. PMID:25228358

  5. Transition Metal Switchable Mirror

    SciTech Connect

    2009-08-21

    The switchable-mirrors technology was developed by Tom Richardson and Jonathan Slack of Berkeley Lab's Environmental Energy Technologies Division. By using transition metals rather than the rare earth metals used in the first metal-hydride switchable mirrors, Richardson and Slack were able to lower the cost and simplify the manufacturing process. Energy performance is improved as well, because the new windows can reflect or transmit both visible and infrared light. Besides windows for offices and homes, possible applications include automobile sunroofs, signs and displays, aircraft windows, and spacecraft.

  6. Mirror nuclei constraint in nuclear mass formula

    SciTech Connect

    Wang Ning; Liang Zuoying; Liu Min; Wu, Xizhen

    2010-10-15

    The macroscopic-microscopic mass formula is further improved by considering mirror nuclei constraint. The rms deviation with respect to 2149 measured nuclear masses is reduced to 0.441 MeV. The shell corrections, the deformations of nuclei, the neutron and proton drip lines, and the shell gaps are also investigated to test the model. The rms deviation of {alpha}-decay energies of 46 superheavy nuclei is reduced to 0.263 MeV. The predicted central position of the superheavy island could lie around N=176{approx}178 and Z=116{approx}120 according to the shell corrections of nuclei.

  7. White-Light Phase-Conjugate Mirrors as Distortion Correctors

    NASA Technical Reports Server (NTRS)

    Frazier, Donald; Smith, W. Scott; Abdeldayem, Hossin; Banerjee, Partha

    2010-01-01

    White-light phase-conjugate mirrors would be incorporated into some optical systems, according to a proposal, as means of correcting for wavefront distortions caused by imperfections in large optical components. The proposal was given impetus by a recent demonstration that white, incoherent light can be made to undergo phase conjugation, whereas previously, only coherent light was known to undergo phase conjugation. This proposal, which is potentially applicable to almost any optical system, was motivated by a need to correct optical aberrations of the primary mirror of the Hubble Space telescope. It is difficult to fabricate large optical components like the Hubble primary mirror and to ensure the high precision typically required of such components. In most cases, despite best efforts, the components as fabricated have small imperfections that introduce optical aberrations that adversely affect imaging quality. Correcting for such aberrations is difficult and costly. The proposed use of white-light phase conjugate mirrors offers a relatively simple and inexpensive solution of the aberration-correction problem. Indeed, it should be possible to simplify the entire approach to making large optical components because there would be no need to fabricate those components with extremely high precision in the first place: A white-light phase-conjugate mirror could correct for all the distortions and aberrations in an optical system. The use of white-light phase-conjugate mirrors would be essential for ensuring high performance in optical systems containing lightweight membrane mirrors, which are highly deformable. As used here, "phase-conjugate mirror" signifies, more specifically, an optical component in which incident light undergoes time-reversal phase conjugation. In practice, a phase-conjugate mirror would typically be implemented by use of a suitably positioned and oriented photorefractive crystal. In the case of a telescope comprising a primary and secondary

  8. Paranal Receives New Mirror

    NASA Astrophysics Data System (ADS)

    2008-04-01

    A 4.1-metre diameter primary mirror, a vital part of the world's newest and fastest survey telescope, VISTA (the Visible and Infrared Survey Telescope for Astronomy) has been delivered to its new mountaintop home at Cerro Paranal, Chile. The mirror will now be coupled with a small camera for initial testing prior to installing the main camera in June. Full scientific operations are due to start early next year. VISTA will form part of ESO's Very Large Telescope facility. ESO PR Photo 10d/08 ESO PR Photo 10d/08 The VISTA Mirror The mirror arrived over the Easter weekend at the Paranal Observatory where the telescope is being assembled at an altitude of 2518m, in Chile's Atacama Desert. VISTA Project Manager Alistair McPherson from STFC's UK Astronomy Technology Centre (UK ATC) accompanied the mirror on its journey to Chile: "This is a major milestone for the VISTA project. The precious mirror was loaded on to a plane in a special cradle that used tennis balls to cushion it from impact for its arduous journey across three continents. " "The mirror had a difficult four-day journey, by air and by road. It arrived in perfect condition and now that it has been coated, we will install the mirror in the telescope with a small test camera for about four weeks testing. We plan to install the main camera in June," said the Project Scientist on VISTA, Will Sutherland of Queen Mary, University of London, UK. The VISTA 4.1-metre diameter primary mirror is the most strongly curved large mirror ever polished to such a precise and exacting surface accuracy - deviations from a perfect surface of less than 1/3000th of the thickness of a human hair. On arrival at Cerro Paranal it was safely craned into the telescope dome where it was washed and coated with a thin layer of protected silver in the facility's coating plant. Silver is the best metal for the purpose since it reflects over 98% of near-infrared light, better than the more commonly used aluminium. To date, the reflectivity

  9. Some Considerations for Precision Metrology of Thin X-Ray Mirrors

    NASA Technical Reports Server (NTRS)

    Lehan, J. P.; Saha, T.; Zhang, W. W.; Rohrbach, S.; Chan, K.-W.; Hadjimichael, T.; Hong, M.; Davis, W.

    2008-01-01

    Determination of the shape of very thin x-ray mirrors employed in spaced-based telescopes continues to be challenging. The mirrors shapes are not readily deduced to the required accuracy because the mount induced distortions are often larger than the uncertainty tolerable for the mission metrology. In addition to static deformations, dynamic and thermal considerations are exacerbated for this class of mirrors. We report on the performance of one temporary mounting scheme for the thin glass mirrors for the Constellation-X mission and prospects for deducing their undistorted shapes.

  10. JWST Mirror Technology Development

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2010-01-01

    Since the initial Design Studies leading to JWST, Mirror Technology was identified as a (if not the) critical capability necessary to enable the next generation of large aperture space telescopes required to achieve the science goals of imaging the earliest galaxies and proto-galaxies after the big bang. Specific telescope architectures were explored via three independent design concept studies conducted during the summer of 1996. Achieving the desired science objectives required a never before demonstrated space telescope capability, one with an 8 meter class primary mirror that is diffraction limited at 2 micrometers and operating in deep space at temperatures well below 70K. Beryllium was identified in the NASA "Yardstick" design as the preferred material because of its ability to provide stable optical performance in the anticipated thermal environment as well as its excellent specific stiffness. Because of launch vehicle constraints, two very significant architectural constraints were placed upon the telescope: segmentation and areal density. Each of these directly resulted in specific technology capability requirements. First, because the maximum launch vehicle payload fairing diameter is approximately 4.5 meters, the only way to launch an 8 meter class mirror is to segment it, fold it and deploy it on orbit - resulting in actuation and control requirements. Second, because of launch vehicle mass limits, the primary mirror allocation was only 1000 kg - resulting in a maximum areal density specification of 20 kilograms per square meter.

  11. Tandem mirror fusion research

    SciTech Connect

    Baldwin, D.E.

    1983-12-02

    The tandem mirror program has evolved considerably in the last decade. Of significance is the viable reactor concept embodied in the MARS design. An aggressive experimental program, culminating in the operation of MFTF-B in late 1986, will provide a firm basis for refining the MARS design as necessary for constructing a reactor prototype in the 1990s.

  12. Rearview Mirror Dimming Function

    ERIC Educational Resources Information Center

    Layton, William

    2011-01-01

    Students are often unaware of the little tab on a rear-view mirror that is used to dim headlights from the rear. Those who know about this tab are usually interested in knowing how it works. Explanations of the optics involved can be found in Serway and Jewett and Jones and Edge. An alternate explanation is given.

  13. Durable metallized polymer mirror

    DOEpatents

    Schissel, Paul O.; Kennedy, Cheryl E.; Jorgensen, Gary J.; Shinton, Yvonne D.; Goggin, Rita M.

    1994-01-01

    A metallized polymer mirror construction having improved durability against delamination and tunneling, comprising: an outer layer of polymeric material; a metal oxide layer underlying the outer layer of polymeric material; a silver reflective layer underneath the metal oxide layer; and a layer of adhesive attaching the silver layer to a substrate.

  14. Durable metallized polymer mirror

    DOEpatents

    Schissel, P.O.; Kennedy, C.E.; Jorgensen, G.J.; Shinton, Y.D.; Goggin, R.M.

    1994-11-01

    A metallized polymer mirror construction is disclosed having improved durability against delamination and tunneling, comprising: an outer layer of polymeric material; a metal oxide layer underlying the outer layer of polymeric material; a silver reflective layer underneath the metal oxide layer; and a layer of adhesive attaching the silver layer to a substrate. 6 figs.

  15. Cosmology with liquid mirror telescopes

    NASA Technical Reports Server (NTRS)

    Hogg, David W.; Gibson, Brad K.; Hickson, Paul

    1993-01-01

    Liquid mirrors provide an exciting means to obtain large optical telescopes for substantially lower costs than conventional technologies. The liquid mirror concept has been demonstrated in the lab with the construction of a diffraction limited 1.5 m mirror. The mirror surface, using liquid mercury, forms a perfect parabolic shape when the mirror cell is rotated at a uniform velocity. A liquid mirror must be able to support a heavy mercury load with minimal flexure and have a fundamental resonant frequency that is as high as possible, to suppress the amplitude of surface waves caused by small vibrations transmitted to the mirror. To minimize the transmission of vibrations to the liquid surface, the entire mirror rests on an air bearing. This necessitates the mirror cell being lightweight, due to the limited load capabilities of the air bearing. The mirror components must also have physical characteristics which minimize the effects of thermal expansion with ambient temperature fluctuations in the observatory. In addition, the 2.7 m mirror construction is designed so that the techniques used may be readily extended to the construction of large mirrors. To attain the goals of a lightweight, rigid mirror, a composite laminant construction was used. The mirror consists of a foam core cut to the desired parabolic shape, with an accuracy of a few mm. An aluminum hub serves as an anchor for the foam and skin, and allows precise centering of the mirror on the air bearing and drive system. Several plys of Kevlar, covered in an epoxy matrix, are then applied to the foam. A final layer of pure epoxy is formed by spin casting. This final layer is parabolic to within a fraction of a mm. An aluminum ring bonded to the circumference of the mirror retains the mercury, and incorporates stainless-steel hard-points for the attachment of balance weights.

  16. Optomechanical analysis and testing of a fast steering secondary mirror prototype for the Giant Magellan Telescope

    NASA Astrophysics Data System (ADS)

    Corredor, Andrew; Park, Won Hyun; Cho, Myung; Kim, Young-Soo

    2013-09-01

    The Giant Magellan Telescope (GMT) will be one of the next class of extremely large segmented mirror telescopes. The GMT will utilize two Gregorian secondary mirrors, and Adaptive Secondary Mirror (ASM) and a Fast-steering Secondary Mirror (FSM). The FSM consists of six off-axis mirrors surrounding a central on-axis circular segment. The segments are 1.1 m in diameter and conjugated 1:1 to the seven 8.4 m segments of the primary. A prototype of the FSM mirror (FSMP) has been developed, analyzed and tested in order to demonstrate the mechanical and optical responses of the mirror assembly when subjected to structural and thermal loadings. In this paper, the mechanical and thermal performances of the FSMP were evaluated by performing finite element analyses (FEA) in NX Nastran. The deformation of the mirror's lateral flexure was measured when the FSMP was axially loaded and the temperature response of the mirror assembly was measured when exposed to a sample thermal environment. In order to validate the mirror/lateral flexure design concept, the mechanical, optical and thermal measurements obtained from the tests conducted on mirrors having two different lateral flexures were compared to the responses calculated by FEA.

  17. MEMS segmented-based adaptive optics scanning laser ophthalmoscope

    PubMed Central

    Manzanera, Silvestre; Helmbrecht, Michael A.; Kempf, Carl J.; Roorda, Austin

    2011-01-01

    The performance of a MEMS (micro-electro-mechanical-system) segmented deformable mirror was evaluated in an adaptive optics (AO) scanning laser ophthalmoscope. The tested AO mirror (Iris AO, Inc, Berkeley, CA) is composed of 37 hexagonal segments that allow piston/tip/tilt motion up to 5 μm stroke and ±5 mrad angle over a 3.5 mm optical aperture. The control system that implements the closed-loop operation employs a 1:1 matched 37-lenslet Shack-Hartmann wavefront sensor whose measurements are used to apply modal corrections to the deformable mirror. After a preliminary evaluation of the AO mirror optical performance, retinal images from 4 normal subjects over a 0.9°x0.9° field size were acquired through a 6.4 mm ocular pupil, showing resolved retinal features at the cellular level. Cone photoreceptors were observed as close as 0.25 degrees from the foveal center. In general, the quality of these images is comparable to that obtained using deformable mirrors based on different technologies. PMID:21559132

  18. Static and dynamic responses of an ultrathin adaptive secondary mirror

    NASA Astrophysics Data System (ADS)

    del Vecchio, Ciro; Brusa, Guido; Gallieni, Daniele; Lloyd-Hart, Michael; Davison, Warren B.

    1999-09-01

    We present the results of a compete set of static and dynamic runs of the FEA model of the MMT adaptive secondary. The thin mirror is the most delicate component of the MMT adaptive secondary unit, as it provides the deformable optical surface able to correct the incoming wavefront. The static performances are evaluated as a function of the various load cases arising form gravitational loads and from the forces deriving from the magnetic interactions between actuators. In addition, computations were performed to assess the dynamic response to the high bandwidth, adaptive correcting force.s In both cases, the performances of the adaptive mirror design are able to accommodate the severe specifications.

  19. Reconstruction of Mirror Foot with Dysplastic Tibia

    PubMed Central

    Deshmukh, Ranjit; Shyam, Ashok K

    2015-01-01

    Introduction: The Mirror foot is a rare congenital anomaly associated with duplication of the structures of the foot. Verghese et al have classified these feet into three types. Type three is associated with a Dysplastic tibia of which only 5 have been reported. Surgical management has been reported in only two of these five cases which are in the form of amputation. Case Report: We would like to present the reconstruction of a Mirror foot associated with a dysplastic tibia. Our case which is only the sixth reported case attempts to present a surgical reconstruction to a plantigrade foot. Reconstruction was attempted in this case since the child showed a good quadriceps function at the knee. Reconstruction consisted of excision of the preaxial polydactyly to achieve a more cosmetic appearance to the foot as well as improve the ability to wear foot wear. The dysplastic tibia was osteotomized to correct the varus deformity and achieve a plantigtade foot. This helped the child to ambulate more easily with a shoe raise and a brace to maintain the correction achieved. At a five year follow up the child was walking and running with a shoe raise for a 9 cm limb length discrepancy. There was however recurrence of the deformity due to fibular overgrowth. The child’s parents refused further reconstruction and were satisfied with the present function and appearance of the child. Conclusion: Reconstruction can therefore be attempted in these limbs associated with good quadriceps function. PMID:27299070

  20. Apparatus and process for removing a predetermined portion of reflective material from mirror

    DOEpatents

    Perry, Stephen J.; Steinmetz, Lloyd L.

    1994-01-01

    An apparatus and process are disclosed for removal of a stripe of soft reflective material of uniform width from the surface of a mirror by using a blade having a large included angle to inhibit curling of the blade during the cutting operation which could result in damage to the glass substrate of the mirror. The cutting blade is maintained at a low blade angle with respect to the mirror surface to produce minimal chipping along the cut edge and to minimize the force exerted on the coating normal to the glass surface which could deform the flat mirror. The mirror is mounted in a cutting mechanism containing a movable carriage on which the blade is mounted to provide very accurate straightness of the travel of the blade along the mirror.

  1. Congenital mirror movements.

    PubMed Central

    Schott, G D; Wyke, M A

    1981-01-01

    In this report are described seven patients assessed clinically and neuropsychologically in whom mirror movements affecting predominantly the hands occurred as a congenital disorder. These mirror movements, representing a specific type of abnormal synkinesia, may arise as a hereditary condition, in the presence of a recognisable underlying neurological abnormality, and sporadically, and the seven patients provide more or less satisfactory examples of each of these three groups. Despite the apparent uniformity of the disorder, the heterogeneity and variability may be marked, examples in some of our patients including the pronounced increase in tone that developed with arm movement, and the capacity for modulation of the associated movement by alteration of neck position and bio-feedback. Various possible mechanisms are considered; these include impaired cerebral inhibition of unwanted movements, and functioning of abnormal motor pathways. Emphasis has been placed on the putative role of the direct, crossed corticomotoneurone pathways and on the unilateral and bilateral cerebral events that precede movement. PMID:7288446

  2. Dynamic coherent backscattering mirror

    PubMed Central

    Xu, M.

    2016-01-01

    The phase of multiply scattered light has recently attracted considerable interest. Coherent backscattering is a striking phenomenon of multiple scattered light in which the coherence of light survives multiple scattering in a random medium and is observable in the direction space as an enhancement of the intensity of backscattered light within a cone around the retroreflection direction. Reciprocity also leads to enhancement of backscattering light in the spatial space. The random medium behaves as a reciprocity mirror which robustly converts a diverging incident beam into a converging backscattering one focusing at a conjugate spot in space. Here we first analyze theoretically this coherent backscattering mirror (CBM) phenomenon and then demonstrate the capability of CBM compensating and correcting both static and dynamic phase distortions occurring along the optical path. CBM may offer novel approaches for high speed dynamic phase corrections in optical systems and find applications in sensing and navigation. PMID:26937296

  3. Dynamic coherent backscattering mirror

    NASA Astrophysics Data System (ADS)

    Zeylikovich, I.; Xu, M.

    2016-02-01

    The phase of multiply scattered light has recently attracted considerable interest. Coherent backscattering is a striking phenomenon of multiple scattered light in which the coherence of light survives multiple scattering in a random medium and is observable in the direction space as an enhancement of the intensity of backscattered light within a cone around the retroreflection direction. Reciprocity also leads to enhancement of backscattering light in the spatial space. The random medium behaves as a reciprocity mirror which robustly converts a diverging incident beam into a converging backscattering one focusing at a conjugate spot in space. Here we first analyze theoretically this coherent backscattering mirror (CBM) phenomenon and then demonstrate the capability of CBM compensating and correcting both static and dynamic phase distortions occurring along the optical path. CBM may offer novel approaches for high speed dynamic phase corrections in optical systems and find applications in sensing and navigation.

  4. Complex/Symplectic Mirrors

    SciTech Connect

    Chuang, Wu-yen; Kachru, Shamit; Tomasiello, Alessandro; /Stanford U., ITP

    2005-10-28

    We construct a class of symplectic non-Kaehler and complex non-Kaehler string theory vacua, extending and providing evidence for an earlier suggestion by Polchinski and Strominger. The class admits a mirror pairing by construction. Comparing hints from a variety of sources, including ten-dimensional supergravity and KK reduction on SU(3)-structure manifolds, suggests a picture in which string theory extends Reid's fantasy to connect classes of both complex non-Kaehler and symplectic non-Kaehler manifolds.

  5. Lightweight Substrates For Mirrors

    NASA Technical Reports Server (NTRS)

    Brown, D. Kyle

    1991-01-01

    New substrate uses conventional quasi-isotropic fabric laminate with surfacing layer of carbon-fiber paper consisting of randomly oriented chopped carbon fibers. Layered structure of fabric and paper relatively easy to manufacture. When impregnated with carbon, structure rigid and stable. Substrates of this type made quite thin, thus keeping areal weights to minimum. Mirrors of this type made faster, and cost less, than predecessors.

  6. Joined Beryllium Mirror Demonstrator

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip; Parsonage, Tom; Burdine, Robert (Technical Monitor)

    2001-01-01

    Fabrications of large Beryllium optical components are fundamentally limited by available facility capabilities. To overcome this limitation, NASA funded Brush Wellman Corp to study a Be joining process. Four 76 mm diameters samples and a 0.5 mm diameter Joined Beryllium Mirror Demonstrator (JBMD) were fabricated. This presentation will review the fabrication of these samples and summarize the results of their cryogenic testing at MSFCs XRCF.

  7. The Multiple Mirror Telescope

    NASA Astrophysics Data System (ADS)

    Beckers, J. M.; Ulich, B. L.; Shannon, R. R.; Carleton, N. P.; Geary, J. C.; Latham, D. W.; Angel, J. R. P.; Hoffmann, W. F.; Low, F. J.; Weymann, R. J.

    The Multiple Mirror Telescope (MMT), located on top of Mount Hopkins (2600 m) in Arizona, consists of six main telescope systems, each of which is a classical Cassegrain with a 1.8 m diameter parabolic primary with focal ratio f/2.7, and a hyperbolic secondary producing a final f/31.6 for each of the individual telescopes. The most significant departures of the MMT from conventional optical telescope technology are (1) the use of light-weight 'egg-crate' mirrors, which reduced the telescope weight, (2) the use of an alt-azimuth mount, which simplifies the gravitational effects on the structure, (3) the use of a ball-bearing support rather than hydrostatic bearings, resulting in cost savings and less maintenance, (4) the use of spur gear drives rather than worm gears, and (5) the use of multiple coaligned light collectors rather than a single monolithic mirror. Early multiple objective telescopes are discussed, and the early history of the MMT project is given. The design and performance of the telescope are explained, and MMT instrumentation (spectrograph, optical design, detector, infrared photometer, SAO CCD camera) is given. Astronomical research with the telescope is discussed, along with plans for future multiple objective telescopes.

  8. Replication of lightweight mirrors

    NASA Astrophysics Data System (ADS)

    Chen, Ming Y.; Matson, Lawrence E.; Lee, Heedong; Chen, Chenggang

    2009-08-01

    The fabrication of lightweight mirror assemblages via a replication technique offers great potential for eliminating the high cost and schedule associated with the grinding and polishing steps needed for conventional glass or SiC mirrors. A replication mandrel is polished to an inverse figure shape and to the desired finish quality. It is then, coated with a release layer, the appropriate reflective layer, and followed by a laminate for coefficient of thermal expansion (CTE) tailorability and strength. This optical membrane is adhered to a mirror structural substrate with a low shrinkage, CTE tailored adhesive. Afterwards, the whole assembly is separated from the mandrel. The mandrel is then cleaned and reused for the next replication run. The ultimate goal of replication is to preserve the surface finish and figure of the optical membrane upon its release from the mandrel. Successful replication requires a minimization of the residual stresses within the optical coating stack, the curing stresses from the adhesive and the thermal stress resulting from CTE mismatch between the structural substrate, the adhesive, and the optical membrane. In this paper, the results on replicated trials using both metal/metal and ceramic/ceramic laminates adhered to light weighted structural substrates made from syntactic foams (both inorganic and organic) will be discussed.

  9. Progress in the Fabrication and Testing of Telescope Mirrors for The James Webb Space Telescope

    NASA Astrophysics Data System (ADS)

    Bowers, Charles W.; Clampin, M.; Feinberg, L.; Keski-Kuha, R.; McKay, A.; Chaney, D.; Gallagher, B.; Ha, K.

    2012-01-01

    The telescope of the James Webb Space Telescope (JWST) is an f/20, three mirror anastigmat design, passively cooled (40K) in an L2 orbit. The design provides diffraction limited performance (Strehl ≥ 0.8) at λ=2μm. To fit within the launch vehicle envelope (Arianne V), the 6.6 meter primary mirror and the secondary mirror support structure are folded for launch, then deployed and aligned in space. The primary mirror is composed of 18 individual, 1.3 meter (flat:flat) hexagonal segments, each adjustable in seven degrees of freedom (six rigid body + radius of curvature) provided by a set of high precision actuators. The actuated secondary mirror ( 0.74m) is similarly positioned in six degrees of rigid body motion. The .70x.51m, fixed tertiary and 0.17m, flat fine steering mirror complete the telescope mirror complement. The telescope is supported by a composite structure optimized for performance at cryogenic temperatures. All telescope mirrors are made of Be with substantial lightweighting (21kg for each 1.3M primary segment). Additional Be mounting and supporting structure for the high precision ( 10nm steps) actuators are attached to the primary segments and secondary mirror. All mirrors undergo a process of thermal stabilization to reduce stress. An extensive series of interferometric measurements guide each step of the polishing process. Final polishing must account for any deformation between the ambient temperature of polishing and the cryogenic, operational temperature. This is accomplished by producing highly precise, cryo deformation target maps of each surface which are incorporated into the final polishing cycle. All flight mirrors have now completed polishing, coating with protected Au and final cryo testing, and the telescope is on track to meet all system requirements. We here review the measured performance of the component mirrors and the predicted performance of the flight telescope.

  10. Mirrors Containing Biomimetic Shape-Control Actuators

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Mouroulis, Pantazis; Bao, Xiaoqi; Sherrit, Stewart

    2003-01-01

    Curved mirrors of a proposed type would comprise lightweight sheets or films containing integral, biologically inspired actuators for controlling their surface figures. These mirrors could be useful in such applications as collection of solar energy, focusing of radio beams, and (provided sufficient precision could be achieved) imaging. These mirrors were originally intended for use in outer space, but it should also be possible to develop terrestrial versions. Several prior NASA Tech Briefs articles have described a variety of approaches to the design of curved, lightweight mirrors containing integral shape-control actuators. The primary distinction between the present approach and the prior approaches lies in the actuator design concept, which involves shapes and movements reminiscent of those of a variety of small, multi-armed animals. The shape and movement of an actuator of this type can also be characterized as reminiscent of that of an umbrella. This concept can be further characterized as a derivative of that of multifinger grippers, the fingers of which are bimorph bending actuators (see Figure 1). The fingers of such actuators can be strips containing any of a variety of materials that have been investigated for use as actuators, including such electroactive polymers as ionomeric polymer/metal composites (IPMCs), ferroelectric polymers, and grafted elastomers. A mirror according to this proposal would be made from a sheet of one of the actuator composites mentioned above. The design would involve many variables, including the pre-curvature and stiffness of the mirror sheet, the required precision of figure control, the required range of variation in focal length (see Figure 2), the required precision of figure control for imaging or non-imaging use, the bending and twisting moments needed to effect the required deformations, and voltage-tomoment coefficients of the actuators, and the voltages accordingly required for actuation. A typical design would call

  11. Spinal deformity.

    PubMed

    Bunnell, W P

    1986-12-01

    Spinal deformity is a relatively common disorder, particularly in teenage girls. Early detection is possible by a simple, quick visual inspection that should be a standard part of the routine examination of all preteen and teenage patients. Follow-up observation will reveal those curvatures that are progressive and permit orthotic treatment to prevent further increase in the deformity. Spinal fusion offers correction and stabilization of more severe degrees of scoliosis. PMID:3786010

  12. Deformation cycles of subduction earthquakes in a viscoelastic Earth.

    PubMed

    Wang, Kelin; Hu, Yan; He, Jiangheng

    2012-04-19

    Subduction zones produce the largest earthquakes. Over the past two decades, space geodesy has revolutionized our view of crustal deformation between consecutive earthquakes. The short time span of modern measurements necessitates comparative studies of subduction zones that are at different stages of the deformation cycle. Piecing together geodetic 'snapshots' from different subduction zones leads to a unifying picture in which the deformation is controlled by both the short-term (years) and long-term (decades and centuries) viscous behaviour of the mantle. Traditional views based on elastic models, such as coseismic deformation being a mirror image of interseismic deformation, are being thoroughly revised. PMID:22517160

  13. The meter-class carbon fiber reinforced polymer mirror and segmented mirror telescope at the Naval Postgraduate School

    NASA Astrophysics Data System (ADS)

    Wilcox, Christopher; Fernandez, Bautista; Bagnasco, John; Martinez, Ty; Romeo, Robert; Agrawal, Brij

    2015-03-01

    The Adaptive Optics Center of Excellence for National Security at the Naval Postgraduate School has implemented a technology testing platform and array of facilities for next-generation space-based telescopes and imaging system development. The Segmented Mirror Telescope is a 3-meter, 6 segment telescope with actuators on its mirrors for system optical correction. Currently, investigation is being conducted in the use of lightweight carbon fiber reinforced polymer structures for large monolithic optics. Advantages of this material include lower manufacturing costs, very low weight, and high durability and survivability compared to its glass counterparts. Design and testing has begun on a 1-meter, optical quality CFRP parabolic mirror for the purpose of injecting collimated laser light through the SMT primary and secondary mirrors as well as the following aft optics that include wavefront sensors and deformable mirrors. This paper will present the design, testing, and usage of this CFRP parabolic mirror and the current path moving forward with this ever-evolving technology.

  14. Alignment and assembly process for primary mirror subsystem of a spaceborne telescope

    NASA Astrophysics Data System (ADS)

    Lin, Wei-Cheng; Chang, Shenq-Tsong; Chang, Sheng-Hsiung; Chang, Chen-Peng; Lin, Yu-Chuan; Chin, Chi-Chieh; Pan, Hsu-Pin; Huang, Ting-Ming

    2015-11-01

    In this study, a multispectral spaceborne Cassegrain telescope was developed. The telescope was equipped with a primary mirror with a 450-mm clear aperture composed of Zerodur and lightweighted at a ratio of approximately 50% to meet both thermal and mass requirements. Reducing the astigmatism was critical for this mirror. The astigmatism is caused by gravity effects, the bonding process, and deformation from mounting the main structure of the telescope (main plate). This article presents the primary mirror alignment, mechanical ground-supported equipment (MGSE), assembly process, and optical performance test used to assemble the primary mirror. A mechanical compensated shim is used as the interface between the bipod flexure and main plate. The shim was used to compensate for manufacturer errors found in components and differences between local coplanarity errors to prevent stress while the bipod flexure was screwed to the main plate. After primary mirror assembly, an optical performance test method called a bench test with an algorithm was used to analyze the astigmatism caused by the gravity effect and deformation from the mounting or supporter. The tolerance conditions for the primary mirror assembly require the astigmatism caused by gravity and mounting force deformation to be less than P-V 0.02 λ at 632.8 nm. The results demonstrated that the designed MGSE used in the alignment and assembly processes met the critical requirements for the primary mirror assembly of the telescope.

  15. A spectrum of shadowed mirroring.

    PubMed

    Wanamaker, Melissa C

    2012-04-01

    The central focus of this paper is to explore and extend Kohut's theory of maternal mirroring and to place it within the current context of psychoanalytic thinking. Kohut believed a child must experience "positive" mirroring from his or her mother in infancy and beyond to ensure development of a healthy self. Kohut alludes, however, to a possible situation in which the mother's face, metaphorically a mirror, can appear "faceless" to her child. From this I have inferred the concept of what I shall call "shadowed mirroring." Clinical and literary examples show that distorted, "shadowed" mirroring appears on a spectrum, with passive mirroring at one end and hostile (either verbal or nonverbal) mirroring on the other; some individuals experience both. I then consider how "shadowed mirroring," especially hostile mirroring, can be understood within the twin contexts of the overall mother-child relationship and present-day Intersubjective/Relational thinking that is both bidirectional and co-constructed. Shadowed mirroring can lead to severe personality dysfunction along the borderline-narcissistic range, as well as to difficulties in the areas of identity formation, failure of self-cohesiveness, and the blunting of certain humane qualities like empathy. PMID:22489812

  16. Theoretical and experimental study on the figuration of a flexible membrane mirror

    NASA Astrophysics Data System (ADS)

    Gao, Ping; Tang, Minxue; Zhang, Gengsheng; Chen, Xinhua; Shen, Weimin; Yu, Jianjun

    2008-12-01

    Based on Karman's equation for symmetrical circular membrane and Qian's theory of circular membrane under the action of uniformly distributed loads in its central portion, the relationship between the curvature of the center cross section of a membrane mirror on a substrate of polyethylene terephthalate (PET) film and the external pressure, and the deviation between the surface shape of the membrane mirror and that of a paraboloid mirror with the same diameter and F/number have been calculated in this paper. The changes of the surface shape of the mirror under various initial boundary conditions and various external pressures applied on it have been analyzed theoretically. An experimental setup for the figuration of a membrane mirror in a diameter of 100mm has been designed and established. The pre-shape of the membrane, the negative air-pressured deformation and the electrostatic deformation were combined to shape a membrane mirror with a relative small curvature radius. The focal lengths of the mirror under different initial boundary condition and different external pressures have been measured and analyzed comparing to that of the theoretical one. The experimental results show the possibility of the method for the figuration of membrane mirrors.

  17. JWST Mirror Technology Development Results

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2007-01-01

    Mirror technology is a critical enabling capability for the James Webb Space Telescope (JWST). JWST requires a Primary Mirror Segment Assembly (PMSA) that can survive launch, deploy and align itself to form a 25 square meter collecting area 6.5 meter diameter primary mirror with a 131 nm rms wavefront error at temperatures less than 50K and provide stable optical performance. At the inception of JWST in 1996, such a capability did not exist. A highly successful technology development program was initiated including the Sub-scale Beryllium Mirror Demonstrator (SBMD) and Advanced Mirror System Demonstrator (AMSD) projects. These projects along with flight program activities have matured and demonstrated mirror technology for JWST. Directly traceable prototypes or flight hardware has been built, tested and operated in a relevant environment. This paper summarizes that technology development effort.

  18. Phase-Controlled Magnetic Mirror for Wavefront Correction

    NASA Technical Reports Server (NTRS)

    Hagopian, John; Wollack, Edward

    2011-01-01

    Typically, light interacts with matter via the electric field and interaction with weakly bound electrons. In a magnetic mirror, a patterned nanowire is fabricated over a metallic layer with a dielectric layer in between. Oscillation of the electrons in the nanowires in response to the magnetic field of incident photons causes a re-emission of photons and operation as a "magnetic mirror." By controlling the index of refraction in the dielectric layer using a local applied voltage, the phase of the emitted radiation can be controlled. This allows electrical modification of the reflected wavefront, resulting in a deformable mirror that can be used for wavefront control. Certain applications require wavefront quality in the few-nanometer regime, which is a major challenge for optical fabrication and alignment of mirrors or lenses. The use of a deformable magnetic mirror allows for a device with no moving parts that can modify the phase of incident light over many spatial scales, potentially with higher resolution than current approaches. Current deformable mirrors modify the incident wavefront by using nano-actuation of a substrate to physically bend the mirror to a desired shape. The purpose of the innovation is to modify the incident wavefront for the purpose of correction of fabrication and alignment-induced wavefront errors at the system level. The advanced degree of precision required for some applications such as gravity wave detection (LISA - Laser Interferometer Space Antenna) or planet finding (FKSI - Fourier-Kelvin Stellar Interferometer) requires wavefront control at the limits of the current state of the art. All the steps required to fabricate a magnetic mirror have been demonstrated. The modification is to apply a bias voltage to the dielectric layer so as to change the index of refraction and modify the phase of the reflected radiation. Light is reflected off the device and collected by a phase-sensing interferometer. The interferometer determines the

  19. SXI prototype mirror mount

    NASA Astrophysics Data System (ADS)

    1995-04-01

    The purpose of this contract was to provide optomechanical engineering and fabrication support to the Solar X-ray Imager (SXI) program in the areas of mirror, optical bench and camera assemblies of the telescope. The Center for Applied Optics (CAO) worked closely with the Optics and S&E technical staff of MSFC to develop and investigate the most viable and economical options for the design and fabrication of a number of parts for the various telescope assemblies. All the tasks under this delivery order have been successfully completed within budget and schedule. A number of development hardware parts have been designed and fabricated jointly by MSFC and UAH for the engineering model of SXI. The major parts include a nickel electroformed mirror and a mirror mount, plating and coating of the ceramic spacers, and gold plating of the contact rings and fingers for the camera assembly. An aluminum model of the high accuracy sun sensor (HASS) was also designed and fabricated. A number of fiber optic tapers for the camera assembly were also coated with indium tin oxide and phosphor for testing and evaluation by MSFC. A large number of the SXI optical bench parts were also redesigned and simplified for a prototype telescope. These parts include the forward and rear support flanges, front aperture plate, the graphite epoxy optical bench and a test fixture for the prototype telescope. More than fifty (50) drawings were generated for various components of the prototype telescope. Some of these parts were subsequently fabricated at UAH machine shop or at MSFC or by the outside contractors. UAH also provide technical support to MSFC staff for a number of preliminary and critical design reviews. These design reviews included PDR and CDR for the mirror assembly by United Technologies Optical Systems (UTOS), and the program quarterly reviews, and SXI PDR and CDR. UAH staff also regularly attended the monthly status reviews, and made a significant number of suggestions to improve

  20. SXI Prototype mirror mount

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This final report describes the work performed from June 1993 to January 1995. The purpose of this contract was to provide optomechanical engineering and fabrication support to the Solar X-ray Imager (SXI) program in the areas of mirror, optical bench and camera assemblies of the telescope. The Center for Applied Optics (CAO) worked closely with the Optics and S&E technical staff of MSFC to develop and investigate the most viable and economical options for the design and fabrication of a number of parts for the various telescope assemblies. All the tasks under this delivery order have been successfully completed within budget and schedule.

  1. SXI prototype mirror mount

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The purpose of this contract was to provide optomechanical engineering and fabrication support to the Solar X-ray Imager (SXI) program in the areas of mirror, optical bench and camera assemblies of the telescope. The Center for Applied Optics (CAO) worked closely with the Optics and S&E technical staff of MSFC to develop and investigate the most viable and economical options for the design and fabrication of a number of parts for the various telescope assemblies. All the tasks under this delivery order have been successfully completed within budget and schedule. A number of development hardware parts have been designed and fabricated jointly by MSFC and UAH for the engineering model of SXI. The major parts include a nickel electroformed mirror and a mirror mount, plating and coating of the ceramic spacers, and gold plating of the contact rings and fingers for the camera assembly. An aluminum model of the high accuracy sun sensor (HASS) was also designed and fabricated. A number of fiber optic tapers for the camera assembly were also coated with indium tin oxide and phosphor for testing and evaluation by MSFC. A large number of the SXI optical bench parts were also redesigned and simplified for a prototype telescope. These parts include the forward and rear support flanges, front aperture plate, the graphite epoxy optical bench and a test fixture for the prototype telescope. More than fifty (50) drawings were generated for various components of the prototype telescope. Some of these parts were subsequently fabricated at UAH machine shop or at MSFC or by the outside contractors. UAH also provide technical support to MSFC staff for a number of preliminary and critical design reviews. These design reviews included PDR and CDR for the mirror assembly by United Technologies Optical Systems (UTOS), and the program quarterly reviews, and SXI PDR and CDR. UAH staff also regularly attended the monthly status reviews, and made a significant number of suggestions to improve

  2. A mirror to analysis.

    PubMed

    Cohen, M

    2000-12-01

    Three books written by psychiatrists for a lay audience are examined. Two are novels, and the third is a psychiatrist's account of the years of his psychiatric residency training. In all three books psychoanalysts are portrayed in negative roles, as arrogant, cold, uncaring, and even venal. The reasons why psychiatrists would portray analysis in this light are examined, and some ways in which psychoanalysts will need to re-examine their role in education and in their relationships with psychiatric colleagues in order to counteract this negative "mirror" are suggested. PMID:11143896

  3. Poco Graphite Mirror Metrology Report

    NASA Technical Reports Server (NTRS)

    Kester, Thomas J.

    2005-01-01

    Recently a lightweight mirror technology was tested at Marshall Space Flight Center's Space Optic Manufacturing Technology Center (MSFC, SOMTC). The mirror is a Poco Graphite CVD Si clad SiC substrate. It was tested for cryogenic (cryo) survivability to 20deg Kelvin in SOMTC's X-ray Calibration and Cryogenic Test Facility. The surface figure of the mirror was measured before and after cry0 cycling. The test technique and results are discussed.

  4. Modularity, quaternion-Kähler spaces, and mirror symmetry

    SciTech Connect

    Alexandrov, Sergei; Banerjee, Sibasish

    2013-10-15

    We provide an explicit twistorial construction of quaternion-Kähler manifolds obtained by deformation of c-map spaces and carrying an isometric action of the modular group SL(2,Z). The deformation is not assumed to preserve any continuous isometry and therefore this construction presents a general framework for describing NS5-brane instanton effects in string compactifications with N= 2 supersymmetry. In this context the modular invariant parametrization of twistor lines found in this work yields the complete non-perturbative mirror map between type IIA and type IIB physical fields.

  5. Numerical simulations of the LBT adaptive secondary mirror

    NASA Astrophysics Data System (ADS)

    Del Vecchio, Ciro; Gallieni, Daniele

    2000-07-01

    In this paper we describe the design of the deformable mirror of the Large Binocular Telescope adaptive secondary unit. Starting from the optical design, a numerical model of the ultra-thin, aspherical glass shell, accommodating the 918 magnets on the selected actuator geometry, has been run. As a result, we can evaluate the response of this crucial component of the telescope optics with great accuracy. The DM is analyzed from the mechanical standpoint -- gravity deformations, wavefront residue, residue of low-order Zernike aberrations, corrections of magnetic interactions -- in order to compute the optical performances in the most demanding operational circumstances.

  6. Scanning mirror for infrared sensors

    NASA Technical Reports Server (NTRS)

    Anderson, R. H.; Bernstein, S. B.

    1972-01-01

    A high resolution, long life angle-encoded scanning mirror, built for application in an infrared attitude sensor, is described. The mirror uses a Moire' fringe type optical encoder and unique torsion bar suspension together with a magnetic drive to meet stringent operational and environmental requirements at a minimum weight and with minimum power consumption. Details of the specifications, design, and construction are presented with an analysis of the mirror suspension that allows accurate prediction of performance. The emphasis is on mechanical design considerations, and brief discussions are included on the encoder and magnetic drive to provide a complete view of the mirror system and its capabilities.

  7. JWST Primary Mirror Technology Development

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2010-01-01

    Mirror Technology was identified as a (if not the) critical capability necessary to achieve the Level 1 science goals. A never before demonstrated space telescope capability was required: 6 to 8 meter class pri mary mirror, diffraction limited at 2 micrometers and operates at temperatures below 50K. Launch vehicle constraints placed significant architectural constraints: deployed/segmented primary mirror (4.5 meter fairing diameter) 20 kg/m2 areal density (PM 1000 kg mass) Such mirror technology had never been demonstrated - and did not exist

  8. Gasdynamic Mirror Fusion Propulsion Experiment

    NASA Astrophysics Data System (ADS)

    Emrich, Bill

    2000-10-01

    A gasdynamic mirror (GDM) fusion propulsion experiment is currently being constructed at the NASA Marshall Space Flight Center (MSFC) to test the feasibility of this particular type of fusion device. Because of the open magnetic field line configuration of mirror fusion devices, they are particularly well suited for propulsion system applications since they allow for the easy ejection of thrust producing plasma. Currently, the MSFC GDM is constructed in three segments. The vacuum chamber mirror segment, the plasma injector mirror segment, and the main plasma chamber segment. Enough magnets are currently available to construct up to three main plasma chamber segments. The mirror segments are also segmented such that they can be expanded to accommodate new end plugging strategies without requiring the disassembly of the entire mirror segment. The plasma for the experiment is generated in a microwave cavity located between the main magnets and the mirror magnets. Ion heating is accomplished through ambipolar diffusion. The objective of the experiment is to investigate the stability characteristics of the gasdynamic mirror and to map a region of parameter space within which the plasma can be confined in a stable steady state configuration. The mirror ratio, plasma density, and plasma ``b" will be varied over a range of values and measurements subsequently taken to determine the degree of plasma stability.

  9. Gasdynamic Mirror Fusion Propulsion Experiment

    NASA Technical Reports Server (NTRS)

    Emrich, Bill; Rodgers, Stephen L. (Technical Monitor)

    2000-01-01

    A gasdynamic mirror (GDM) fusion propulsion experiment is currently being constructed at the NASA Marshall Space Flight Center (MSFC) to test the feasibility of this particular type of fusion device. Because of the open magnetic field line configuration of mirror fusion devices, they are particularly well suited for propulsion system applications since they allow for the easy ejection of thrust producing plasma. Currently, the MSFC GDM is constructed in three segments. The vacuum chamber mirror segment, the plasma injector mirror segment, and the main plasma chamber segment. Enough magnets are currently available to construct up to three main plasma chamber segments. The mirror segments are also segmented such that they can be expanded to accommodate new end plugging strategies with out requiring the disassembly of the entire mirror segment. The plasma for the experiment is generated in a microwave cavity located between the main magnets and the mirror magnets. Ion heating is accomplished through ambipolar diffusion. The objective of the experiment is to investigate the stability characteristics of the gasdynamic mirror and to map a region of parameter space within which the plasma can be confined in a stable steady state configuration. The mirror ratio, plasma density, and plasma "b" will be varied over a range of values and measurements subsequently taken to determine the degree of plasma stability.

  10. Unconventional adaptive mirrors at the University of Arizona

    NASA Astrophysics Data System (ADS)

    Hart, Michael; Ammons, S. Mark; Coughenour, Blake; Romeo, Robert

    2012-06-01

    We describe the construction and application of innovative deformable mirrors for adaptive optics (AO) being developed at the University of Arizona's Center for Astronomical Adaptive Optics. The mirrors are up to 1 m in diameter, with high actuator stroke, and are optically powered. Scientific motivations for the work include the detection of earthlike planets around other nearby stars, as well as non-astronomical applications such as directed energy and horizontal imaging for defense and security. We describe how high resolution imaging is delivered over an unusually wide field of view by ground-layer AO. This technique employs multiple laser guide stars to sense the instantaneous three-dimensional distribution of atmospheric turbulence. Imaging with high signal-to-noise ratio in the thermal infrared is enabled by embedding the deformable mirror directly in the telescope. We also describe recent work to develop a new generation of these mirrors with lighter weight and improved robustness by use of replicated composite materials which shows promise for greatly reducing the cost of AO and broadening its appeal, particularly for non-astronomical applications as well as for a new generation of extremely large ground-based telescopes of 30 m diameter now under construction.

  11. Optimal glass-ceramic structures: Components of giant mirror telescopes

    NASA Technical Reports Server (NTRS)

    Eschenauer, Hans A.

    1990-01-01

    Detailed investigations are carried out on optimal glass-ceramic mirror structures of terrestrial space technology (optical telescopes). In order to find an optimum design, a nonlinear multi-criteria optimization problem is formulated. 'Minimum deformation' at 'minimum weight' are selected as contradictory objectives, and a set of further constraints (quilting effect, optical faults etc.) is defined and included. A special result of the investigations is described.

  12. Quaternary deformation

    SciTech Connect

    Brown, R.D. Jr.

    1990-01-01

    Displaced or deformed rock units and landforms record the past 2 m.y. of faulting, folding, uplift, and subsidence in California. Properly interpreted, such evidence provides a quantitative basis for predicting future earthquake activity and for relating many diverse structures and landforms to the 5 cm/yr of horizontal motion at the boundary between the North American and Pacific plates. Modern techniques of geologic dating and expanded research on earthquake hazards have greatly improved our knowledge of the San Andreas fault system. Much of this new knowledge has been gained since 1965, and that part which concerns crustal deformation during the past 2 m.y. is briefly summarized here.

  13. Relay mirror experiment

    NASA Astrophysics Data System (ADS)

    Begley, David L.

    1996-04-01

    Originating out of a SDIO-funded, Phase 1 study effort, two ground systems and an orbiting EO payload/spacecraft were the primary equipment for the RME. The RME was originally conceived to be a shuttle deployed experiment. Shortly after program start, the Challenger disaster occurred, with the promise of extensive delays. A completely new space segment was to be designed incorporating a free-flying spacecraft. During the midphase of the program, a variety of launch vehicles were envisioned to replace the shuttle, requiring the BASD team to design accommodations for Delta, Atlas, and Titan, with a Delta launch being the final solution. The ground systems tracked the spacecraft and illuminated it with green and blue beacon lasers. The Payload Experiment Package (PEP) housed the bisection tracker, a key innovation central to the experiment. The bisection tracker acquired both beacons and controlled steerable mirrors to accomplish fine tracking of the two cooperative beacons. In the process, the relay mirror was precisely positioned to enable a successful relay of a third infrared laser between the two ground sites via the orbiting spacecraft. Many of the key technologies employed in the PEP were originally developed for Ball laser communications research and development programs and other laser pointing efforts. The WAVE sensor package, built by ATA and integrated by Ball, measured the vibrations of the optical base structure on which it was mounted. These spacecraft vibration data are critical to the accurate pointing of space laser communication terminals.

  14. Ultrasonic Time Reversal Mirrors

    NASA Astrophysics Data System (ADS)

    Fink, Mathias; Montaldo, Gabriel; Tanter, Mickael

    2004-11-01

    For more than ten years, time reversal techniques have been developed in many different fields of applications including detection of defects in solids, underwater acoustics, room acoustics and also ultrasound medical imaging and therapy. The essential property that makes time reversed acoustics possible is that the underlying physical process of wave propagation would be unchanged if time were reversed. In a non dissipative medium, the equations governing the waves guarantee that for every burst of sound that diverges from a source there exists in theory a set of waves that would precisely retrace the path of the sound back to the source. If the source is pointlike, this allows focusing back on the source whatever the medium complexity. For this reason, time reversal represents a very powerful adaptive focusing technique for complex media. The generation of this reconverging wave can be achieved by using Time Reversal Mirrors (TRM). It is made of arrays of ultrasonic reversible piezoelectric transducers that can record the wavefield coming from the sources and send back its time-reversed version in the medium. It relies on the use of fully programmable multi-channel electronics. In this paper we present some applications of iterative time reversal mirrors to target detection in medical applications.

  15. Mirror development for CTA

    NASA Astrophysics Data System (ADS)

    Förster, A.; Doro, M.; Brun, P.; Canestrari, R.; Chadwick, P.; Font, L.; Ghigo, M.; Lorenz, E.; Mariotti, M.; Michalowski, J.; Niemiec, J.; Pareschi, G.; Peyaud, B.; Seweryn, K.

    2009-08-01

    The Cherenkov Telescope Array (CTA), currently in its early design phase, is a proposed new project for groundbased gamma-ray astronomy with at least 10 times higher sensitivity than current instruments. CTA is planned to consist of several tens of large Imaging Atmospheric Cherenkov Telescopes (IACTs) with a combined reflective surface of up to 10,000 m2. The challenge for the future CTA array is to develop lightweight and cost efficient mirrors with high production rates, good longterm durability and adequate optical properties. The technologies currently under investigation comprise different methods of carbon fibre/epoxy based substrates, sandwich concepts with cold-slumped surfaces made of thin float glass and different structural materials like aluminum honeycomb, glass foam or PU foam inside, and aluminum sandwich structures with either diamond milled surfaces or reflective foils. The current status of the mirror development for CTA will be summarized together with investigations on the improvement of the reflective surfaces and their protection against degradation.

  16. "Mirror-Image" Errors without Mirror-Image Stimuli

    ERIC Educational Resources Information Center

    Barroso, Felix; Braine, Lila Ghent

    1974-01-01

    Young children matching the orientation of (a) identical realistic figures that could form mirror images of each other, or (b) nonidentical realistic figures that could not form mirror images, produced the same pattern of errors. The explanation proposed is a strategy of matching analogous parts of the two figures. (Author/SDH)

  17. Development of lightweight mirror elements for the Euro50 mirrors

    NASA Astrophysics Data System (ADS)

    Bennett, Harold E.; Romeo, Robert C.; Shaffer, Joseph J.; Chen, Peter C.

    2004-07-01

    New, very large telescopes with apertures of 30, 50, and 100 meters are being proposed by the astronomical community. Superpolished or ultrapolished mirrors with low scattered light levels and the use of adaptive optics for near-diffraction-limited performance would make such large telescopes a turning point in astronomy. The secondary mirror for the Euro50 will be a four meter adaptive optic made of a low expansion graphite-filled cyanate ester resin composite produced using a replica transfer technique. We have made three 1/3rd meter diameter prototype composite adaptive optic mirrors of this cyanate ester composite material. Because of the embedded graphite fibers, the composite material has a measured expansion coefficient in the 10-8 range, as has Zerodur or ULE glass. It is very much lighter, more rugged and more economical than Zerodur or ULE, and can be fabricated in weeks, not months. The Zerodur mandrels upon which these replica transfer mirrors are made are superpolished using centrifugal elutriation, so the replica surface has an rms roughness of 0.6 to 0.8 nm. It thus scatters about an order of magnitude less light than typical conventionally polished astronomical mirrors. In adaptive optic mirrors with sub-mm thick faceplates the number of plies used is insufficient to produce an isotropic surface. For mirrors 2 mm thick, with more plies, the surfaces are isotropic, and the slight astigmatism sometimes resulting from the mesh in the ply can be corrected by actuators to make them attractive mirrors. They must be supported to maintain a good optical figure over a meter diameter mirror. The support requirement may be met by using a new type of mechanical/piezoelectric actuator adjustable to a fraction of a wavelength. The mechanical actuators have a coarse adjust of over an mm and a fine adjust of less than a wavelength of light. They can be used in series with a novel type of piezoelectric actuator for final static adjustment. The low voltage, up to 2

  18. Mirror profile optimization for nano-focusing KB mirror

    SciTech Connect

    Zhang Lin; Baker, Robert; Barrett, Ray; Cloetens, Peter; Dabin, Yves

    2010-06-23

    A KB focusing mirror width profile has been optimized to achieve nano-focusing for the nano-imaging end-station ID22NI at the ESRF. The complete mirror and flexure bender assembly has been modeled in 3D with finite element analysis using ANSYS. Bender stiffness, anticlastic effects and geometrical non-linear effects have been considered. Various points have been studied: anisotropy and crystal orientation, stress in the mirror and bender, actuator resolution and the mirror-bender adhesive bonding... Extremely high performance of the mirror is expected with residual slope error smaller than 0.6 {mu}rad, peak-to-valley, compared to the bent slope of 3000 {mu}rad.

  19. Deformation of rectangular thin glass plate coated with magnetostrictive material

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoli; Yao, Youwei; Liu, Tianchen; Liu, Chian; Ulmer, M. P.; Cao, Jian

    2016-08-01

    As magnetic smart materials (MSMs), magnetostrictive materials have great potential to be selected as coating materials for lightweight x-ray telescope mirrors due to their capability to tune the mirror profile to the desired shape under a magnetic field. To realize this potential, it is necessary to study the deformation of the mirror substrate with the MSM coating subjected to a localized magnetic field. In this paper, an analytical model is developed to calculate the deformation of rectangular coated samples locally affected by magnetostrictive strains driven by an external magnetic field. As a specific case to validate the model, a square glass sample coated with MSMs is prepared, and its deformation is measured in a designed experimental setup by applying a magnetic field. The measured deformation of the sample is compared with the results calculated from the analytical model. The comparison results demonstrate that the analytical model is effective in calculating the deformation of a coated sample with the localized mismatch strains between the film and the substrate. In the experiments, different shape patterns of surface profile changes are achieved by varying the direction of the magnetic field. The analytical model and the experimental method proposed in this paper can be utilized to further guide the application of magnetostrictive coating to deformable lightweight x-ray mirrors in the future.

  20. Madelung deformity.

    PubMed

    Ghatan, Andrew C; Hanel, Douglas P

    2013-06-01

    Madelung deformity is a rare congenital anomaly of the wrist caused by asymmetric growth at the distal radial physis secondary to a partial ulnar-sided arrest. The deformity is characterized by ulnar and palmar curvature of the distal radius, positive ulnar variance, and proximal subsidence of the lunate. It more commonly occurs in females than males and typically affects both wrists. The deformity can occur in isolation or as part of a genetic syndrome. The pattern of inheritance varies, with some cases following a pseudoautosomal pattern and many others lacking a clear family history. Nonsurgical management is typically advocated in asymptomatic patients. Few studies exist on the natural history of the condition; however, extensor tendon ruptures have been reported in severe and chronic cases. Stiffness, pain, and patient concerns regarding wrist cosmesis have been cited as indications for surgery. Various techniques for surgical management of Madelung deformity have been described, but clear evidence to support the use of any single approach is lacking. PMID:23728962

  1. Extracting Zero-Gravity Surface Figure of a Mirror

    NASA Technical Reports Server (NTRS)

    Bloemhof, Eric E.; Lam, Jonathan C.; Feria, Alfonso; Chang, Zensheu

    2011-01-01

    The technical innovation involves refinement of the classic optical technique of averaging surface measurements made in different orientations with respect to gravity, so the effects of gravity cancel in the averaged image. Particularly for large, thin mirrors subject to substantial deformation, the further requirement is that mount forces must also cancel when averaged over measurement orientations. The zerogravity surface figure of a mirror in a hexapod mount is obtained by analyzing the summation of mount forces in the frame of the optic as surface metrology is averaged over multiple clockings. This is illustrated with measurements taken from the Space Interferometry Mission (SIM) PT-Ml mirror for both twofold and threefold clocking. The positive results of these measurements and analyses indicate that, from this perspective, a lighter mirror could be used; that is, one might place less reliance on the damping effects of the elliptic partial differential equations that describe the propagation of forces through glass. The advantage over prior art is relaxing the need for an otherwise substantial thickness of glass that might be needed to ensure accurate metrology in the absence of a detailed understanding and analysis of the mount forces. The general insights developed here are new, and provide the basic design principles on which mirror mount geometry may be chosen.

  2. Thermal Model Development for an X-Ray Mirror Assembly

    NASA Technical Reports Server (NTRS)

    Bonafede, Joseph A.

    2015-01-01

    Space-based x-ray optics require stringent thermal environmental control to achieve the desired image quality. Future x-ray telescopes will employ hundreds of nearly cylindrical, thin mirror shells to maximize effective area, with each shell built from small azimuthal segment pairs for manufacturability. Thermal issues with these thin optics are inevitable because the mirrors must have a near unobstructed view of space while maintaining near uniform 20 C temperature to avoid thermal deformations. NASA Goddard has been investigating the thermal characteristics of a future x-ray telescope with an image requirement of 5 arc-seconds and only 1 arc-second focusing error allocated for thermal distortion. The telescope employs 135 effective mirror shells formed from 7320 individual mirror segments mounted in three rings of 18, 30, and 36 modules each. Thermal requirements demand a complex thermal control system and detailed thermal modeling to verify performance. This presentation introduces innovative modeling efforts used for the conceptual design of the mirror assembly and presents results demonstrating potential feasibility of the thermal requirements.

  3. Forming Mirrors on Composite Materials

    NASA Technical Reports Server (NTRS)

    Gauldin, R. E.; Ramohalli, K.

    1983-01-01

    Smooth coatings deposited on hard-to-polish substrates. Lightweight mirror, leaning against conventional glass mirror, consists of metallic relective layer on substrate coated with polyester resin. Smooth surface of polyester resin made by covering freshly applied resin with piece of smooth glass coated with release agent.

  4. Polishing technique for beryllium mirror

    NASA Technical Reports Server (NTRS)

    Froechtenigt, J. F.

    1976-01-01

    Performance tests, accomplished by inserting entire X ray telescope and polished mirror into vacuum line 67 m long and taking photographs of an X ray resolution source, indicate that polishing increases mirror efficiency from 0.06 percent for X rays at 0.8 nm and increases resolution from 15 to 3.75 arc-seconds.

  5. Acoustic Models of Optical Mirrors

    ERIC Educational Resources Information Center

    Mayer, V. V.; Varaksina, E. I.

    2014-01-01

    Students form a more exact idea of the action of optical mirrors if they can observe the wave field being formed during reflection. For this purpose it is possible to organize model experiments with flexural waves propagating in thin elastic plates. The direct and round edges of the plates are used as models of plane, convex and concave mirrors.…

  6. Knife-edge test for characterization of subnanometer deformations in micro-optical surfaces

    NASA Astrophysics Data System (ADS)

    Zamkotsian, Frederic; Dohlen, Kjetil; Lanzoni, Patrick; Mazzanti, Silvio; Michel, Marie-Laurence; Buat, Veronique; Burgarella, Denis

    1999-11-01

    Development of accurate surface characterization methods is essential for testing micro-optical components, such as micro- opto-electro-mechanical systems (MOEMS), for use in complex optical systems. We consider using an array of 16 micrometer- wide micro-mirrors as programmable slits for astronomical multi-object spectroscopy, and propose a new method based upon Foucault's knife-edge test to characterize local surface deformations of individual micro-mirrors. By measuring local slopes, the surface shape of each mirror in a micro-mirror array has been reconstructed with a sub-nanometer accuracy. In addition to low-order deformation (tilt, curvature, astigmatism), each mirror is seen to be palm-tree shaped. We have checked the validity of our knife-edge test by the micro- characterization of a conventional spherical mirror.

  7. Generation-X mirror technology development plan and the development of adjustable x-ray optics

    NASA Astrophysics Data System (ADS)

    Reid, Paul B.; Davis, William; O'Dell, Stephen; Schwartz, Daniel A.; Tolier-McKinstry, Susan; Wilke, Rudeger H. T.; Zhang, William

    2009-08-01

    Generation-X is being studied as an extremely high resolution, very large area grazing incidence x-ray telescope. Under a NASA Advanced Mission Concepts Study, we have developed a technology plan designed to lead to the 0.1 arcsec (HPD) resolution adjustable optics with 50 square meters of effective area necessary to meet Generation-X requirements. We describe our plan in detail. In addition, we report on our development activities of adjustable grazing incidence optics via the fabrication of bimorph mirrors. We have successfully deposited thin-film piezo-electric material on the back surface of thin glass mirrors. We report on the electrical and mechanical properties of the bimorph mirrors. We also report on initial finite element modeling of adjustable grazing incidence mirrors; in particular, we examine the impact of how the mirrors are supported - the boundary conditions - on the deformations which can be achieved.

  8. Electrons and Mirror Symmetry

    ScienceCinema

    Kumar, Krishna

    2009-09-01

    The neutral weak force between an electron and a target particle, mediated by the Z boson, can be isolated by measuring the fractional change under a mirror reflection of the scattering probability of relativistic longitudinally polarized electrons off unpolarized targets. This technique yields neutral weak force measurements at a length scale of 1 femtometer, in contrast to high energy collider measurements that probe much smaller length scales. Study of the variation of the weak force over a range of length scales provides a stringent test of theory, complementing collider measurements. We describe a recent measurement of the neutral weak force between two electrons by the E158 experiment at the Stanford Linear Accelerator Center. While the weak force between an electron and positron has been extensively studied, that between two electrons had never directly been measured. We conclude by discussing prospects for even more precise measurements at future facilities.

  9. Electrons and Mirror Symmetry

    SciTech Connect

    Kumar, Krishna

    2007-04-04

    The neutral weak force between an electron and a target particle, mediated by the Z boson, can be isolated by measuring the fractional change under a mirror reflection of the scattering probability of relativistic longitudinally polarized electrons off unpolarized targets. This technique yields neutral weak force measurements at a length scale of 1 femtometer, in contrast to high energy collider measurements that probe much smaller length scales. Study of the variation of the weak force over a range of length scales provides a stringent test of theory, complementing collider measurements. We describe a recent measurement of the neutral weak force between two electrons by the E158 experiment at the Stanford Linear Accelerator Center. While the weak force between an electron and positron has been extensively studied, that between two electrons had never directly been measured. We conclude by discussing prospects for even more precise measurements at future facilities.

  10. Adaptive secondary mirror for the 6.5-m conversion of the Multiple Mirror Telescope: first laboratory testing results

    NASA Astrophysics Data System (ADS)

    Brusa, Guido; Riccardi, Armando; Biliotti, Valdemaro; del Vecchio, Ciro; Salinari, Piero; Stefanini, Paolo; Mantegazza, Paolo; Biasi, Roberto; Andrighettoni, Mario; Franchini, Claudio; Gallieni, Daniele

    1999-09-01

    We present the first results of test performed on a reduced size adaptive secondary prototype named P36. The full size unit, named MMT336, is ready to be assembled and it is planned to install it at the 6.5m conversion of the Multiple Mirror Telescope by the end of this year. The design of the final unit consists of: a convex thin deformable mirror whose figure is controlled by 336 electro-magnetic force actuators, a thick reference shell and a third aluminum shell used for actuator support and cooling. The force actuator response function is adjusted using both open and closed loop compensation to obtain an equivalent position actuator thanks to nearly co-located capacitive position sensors. The digital real-time control and the unit monitoring is done using custom-made electronics based on DSPs. The preliminary dynamical test aimed at identifying the P36 mirror response function to obtain a proper dynamics compensation were successful. In fact two main results have been obtained: 1) an accurate identification of the feedforward matrix used to control the mirror 2) settling time of approximately 0.5 ms, well within the specifications. We also complement these lab results with results obtained from simulations of the full size mirror dynamics.

  11. Cryogenic optical measurements of 12-segment-bonded carbon-fiber-reinforced silicon carbide composite mirror with support mechanism.

    PubMed

    Kaneda, Hidehiro; Nakagawa, Takao; Onaka, Takashi; Enya, Keigo; Makiuti, Sin'itirou; Takaki, Junji; Haruna, Masaki; Kume, Masami; Ozaki, Tsuyoshi

    2008-03-10

    A 720 mm diameter 12-segment-bonded carbon-fiber-reinforced silicon carbide (C/SiC) composite mirror has been fabricated and tested at cryogenic temperatures. Interferometric measurements show significant cryogenic deformation of the C/SiC composite mirror, which is well reproduced by a model analysis with measured properties of the bonded segments. It is concluded that the deformation is due mostly to variation in coefficients of thermal expansion among segments. In parallel, a 4-degree-of-freedom ball-bearing support mechanism has been developed for cryogenic applications. The C/SiC composite mirror was mounted on an aluminum base plate with the support mechanism and tested again. Cryogenic deformation of the mirror attributed to thermal contraction of the aluminum base plate via the support mechanism is highly reduced by the support, confirming that the newly developed support mechanism is promising for its future application to large-aperture cooled space telescopes. PMID:18327285

  12. Poco Graphite Inc. SuperSiC 0.25m Mirror Cryogenic Test Result

    NASA Technical Reports Server (NTRS)

    Eng, Ron; Stahl, Phil; Hogue, Bill; Hadaway, James

    2004-01-01

    SuperSiC, a low areal density material, developed by POCO Graphite, have been used as mirror substrate for high energy lasers, laser radar systems, surveillance, telescopes, scan mirrors and satellites. SuperSiC has excellent thermal properties and cryogenic stability. It exhibits exceptional polishability for reflective optics with high strength, stiffness, and excellent thermal conductivity. A lightweighted 0.2-diameter polished SuperSic mirror was tested at cryogenic temperature at NASMSFC. Optical test results showed 6nm cry0 deformation from ambient to 30 degrees Kelvin and little to no change in its surface figure due to cry0 cycling.

  13. Delivery of the Second Generation VLT Secondary Mirror (M2) Unit to ESO

    NASA Astrophysics Data System (ADS)

    Arsenault, R.; Vernet, E.; Madec, P.-Y.; Lizon, J.-L.; Duhoux, P.; Conzelmann, R.; Hubin, N.; Biasi, R.; Andrighettoni, M.; Angerer, G.; Pescoller, D.; Mair, C.; Picin, F.; Gallieni, D.; Lazzarini, P.; Anaclerio, E.; Mantegazza, M.; Fumi, L.; Riccardi, A.; Briguglio, R.; Poutriquet, F.; Ruch, E.; Rinchet, A.; Carré, J.-F.; Fappani, D.

    2013-03-01

    The deformable secondary mirror (DSM), one of the key systems of the VLT Adaptive Optics Facility (AOF), has been delivered to ESO. It has been fully qualified in standalone mode and has successfully passed the technical acceptance Europe. Recently it was installed on ASSIST, the test bench for the AOF, and will undergo optical tests, which will complete its preliminary acceptance in Europe. With its 1170 actuators and 1.1-metre thin-shell mirror, it constitutes the largest adaptive optics mirror ever produced. The DSM constitutes a fine accomplishment by European industry and is set to become the "flagship" of the AOF on Paranal.

  14. The kinaesthetic mirror illusion: How much does the mirror matter?

    PubMed

    Chancel, Marie; Brun, Clémentine; Kavounoudias, Anne; Guerraz, Michel

    2016-06-01

    The reflection of a moving hand in a mirror positioned in the sagittal plane can create an illusion of symmetrical, bimanual movement. This illusion is implicitly presumed to be of visual origin. However, muscle proprioceptive afferents of the arm reflected in the mirror might also affect the perceived position and movement of the other arm. We characterized the relative contributions of visual and proprioceptive cues by performing two experiments. In Experiment 1, we sought to establish whether kinaesthetic illusions induced using the mirror paradigm would survive marked visual impoverishment (obtained by covering between 0 and 100 % of the mirror in 16 % steps). We found that the mirror illusion was only significantly influenced when the visual degradation was 84 % or more. In Experiment 2, we masked the muscle proprioceptive afferents of the arm reflected in the mirror by co-vibrating antagonistic muscles. We found that masking the proprioceptive afferents reduced the velocity of the illusory displacement of the other arm. These results confirm that the mirror illusion is not a purely visual illusion but emerges from a combination of congruent signals from the two arms, i.e. visual afferents from the virtually moving arm and proprioceptive afferents from the contralateral, moving arm. PMID:26790422

  15. Mirror man: a case of skilled deliberate mirror writing.

    PubMed

    McIntosh, Robert D; De Lucia, Natascia; Della Sala, Sergio

    2014-01-01

    Mirror writing is a striking behaviour that is common in children and can reemerge in adults following brain damage. Skilled deliberate mirror writing has also been reported, but only anecdotally. We provide the first quantitative study of skilled deliberate mirror writing. K.B. can write forward or backward, vertically upright or inverted, with the hands acting alone or simultaneously. K.B. is predominantly left handed, but writes habitually with his right hand. Of his writing formats, his left hand mirror writing is by far the most similar in style to his normal handwriting. When writing bimanually, he performs better when his two hands make mirror-symmetrical movements to write opposite scripts than if they move in the same direction to write similar scripts. He has no special facility for reading mirrored text. These features are consistent with prior anecdotal cases and support a motor basis for K.B.'s ability, according to which his skilled mirror writing results from the left hand execution of a low-level motor program for a right hand abductive writing action. Our methods offer a novel framework for investigating the sharing of motor representations across effectors. PMID:24593311

  16. Point Relay Scanner Utilizing Ellipsoidal Mirrors

    NASA Technical Reports Server (NTRS)

    Manhart, Paul K. (Inventor); Pagano, Robert J. (Inventor)

    1997-01-01

    A scanning system uses a polygonal mirror assembly with each facet of the polygon having an ellipsoidal mirror located thereon. One focal point of each ellipsoidal mirror is located at a common point on the axis of rotation of the polygonal mirror assembly. As the mirror assembly rotates. a second focal point of the ellipsoidal mirrors traces out a scan line. The scanner can be utilized for scanned output display of information or for scanning information to be detected.

  17. Topology optimization-based lightweight primary mirror design of a large-aperture space telescope.

    PubMed

    Liu, Shutian; Hu, Rui; Li, Quhao; Zhou, Ping; Dong, Zhigang; Kang, Renke

    2014-12-10

    For the large-aperture space telescope, the lightweight primary mirror design with a high-quality optical surface is a critical and challenging issue. This work presents a topology optimization-based design procedure for a lightweight primary mirror and a new mirror configuration of a large-aperture space telescope is obtained through the presented design procedure. Inspired by the topology optimization method considering cast constraints, an optimization model for the configuration design of the mirror back is proposed, through which the distribution and the heights of the stiffeners on the mirror back can be optimized simultaneously. For the purpose of minimizing the optical surface deviation due to self-weight and polishing pressure loadings, the objective function is selected as to maximize the mirror structural stiffness, which can be achieved by minimizing the structural compliance. The total mass of the primary mirror is assigned as the constraint. In the application example, results of the optimized design topology for two kinds of mass constraints are presented. Executing the design procedure for specific requirements and postprocessing the topology obtained of the structure, a new mirror configuration with tree-like stiffeners and a multiple-arch back in double directions is proposed. A verification model is constructed to evaluate the design results and the finite element method is used to calculate the displacement of the mirror surface. Then the RMS deviation can be obtained after fitting the deformed surface by Zernike polynomials. The proposed mirror is compared with two classical mirrors in the optical performance, and the comparison results demonstrate the superiority of the new mirror configuration. PMID:25608076

  18. Status on NGST Mirror Technology

    NASA Technical Reports Server (NTRS)

    Jacobson, David

    2000-01-01

    The NGST primary mirror is anticipated to be a segmented deployable optic with segment size being in the range of 1 - 3 m depending on the details of the architecture. The secondary mirror will likely be a monolith similar in size to one of the primary mirror segments. Over the past 4 years the NGST program has initiated and implemented an aggressive lightweight cryogenic mirror technology program. The program was designed to challenge and excite the optical community in reaching a new standard in production of lightweight optics. The goal was to develop optics at less than 15 kg/sq m, operational at approx. 40 K and meeting the overall NGST observatory requirement for diffraction limited performance at 2 microns. In order to meet the NGST needs, technology efforts were initiated to investigate and develop mirrors in a variety of materials, which held promise for the program. The basic technology approaches have initially targeted the production of large mirrors in the 1.2 - 2.0 m diameter range (or side-to-side distance in the case of hexagonal optics). Although this size may not be the final size of an NGST primary mirror segment, it was felt that a 1.2 - 2.0 m optic would be of sufficient size to understand the mirror material and fabrication processes which drive the cost and schedule of mirror production. The ultimate goals of the technology program are both to demonstrate mirrors meeting, the NGST performance requirements, and to establish cost and schedule credibility for producing and implementing the mirrors for the NGST flight system. Establishing cost and schedule credibility is essential to NGST which is a cost capped mission, with past program experience demonstrating that the optics will be a large portion of the total cost of the program. The first two years of the program were dedicated to understanding; the various applicable materials, funding those materials to various levels of maturity and implementing the first large mirror procurement, the

  19. A method on lightweight for the primary mirror of large space-based telescope based on neural network

    NASA Astrophysics Data System (ADS)

    Wang, Dawei; Zhang, Shuqing; Tan, Fanjiao; Zhi, Xiyang; Chu, Yongqiang; Lv, Hongdi; Zhen, Rongkai

    2014-11-01

    With the aperture of telescope becoming larger, the mass of primary mirror and other relevant structures will become heavier as well. Therefore, lighting weight for large space-based telescope is necessary. This paper purposed a method based on Neural Network aims to build a math model for primary mirror of large space-based telescope, which can reduce weight of the telescope and smaller mirror deformation caused by gravity release effectively. In the meantime, it can also improve stiffness of structure and reduce thermal strain caused by on orbit temperature variation effectively. The model describes the relationship between the structure of primary mirror of large space-based telescope and corresponding deformation, and describes the optical performance of mirror by using Zernike Polynomial. To optimize the structure of primary mirror lightweight, we take the deformation of mirror and its optical performance into consideration. To apply the structures parameters and its corresponding deformations to Neural Network training, we use the combination samples of different mirror lightweight structure parameters and corresponding deformation which caused by gravity release and thermal condition. Finally, by taking advantage of the Neural Network model to optimize the primary mirror lightweight of 1-meter rectangle space-based telescope, which can make the RMS 0.024λ (λ=632.8nm)and areal density under 15kg/m2. This method combines existing results and numerical simulation to establish numerical model based on Neural Network method. Research results can be applied to same processes of designing, analyzing, and processing of large space-based telescope directly.

  20. Advanced Mirror & Modelling Technology Development

    NASA Technical Reports Server (NTRS)

    Effinger, Michael; Stahl, H. Philip; Abplanalp, Laura; Maffett, Steven; Egerman, Robert; Eng, Ron; Arnold, William; Mosier, Gary; Blaurock, Carl

    2014-01-01

    The 2020 Decadal technology survey is starting in 2018. Technology on the shelf at that time will help guide selection to future low risk and low cost missions. The Advanced Mirror Technology Development (AMTD) team has identified development priorities based on science goals and engineering requirements for Ultraviolet Optical near-Infrared (UVOIR) missions in order to contribute to the selection process. One key development identified was lightweight mirror fabrication and testing. A monolithic, stacked, deep core mirror was fused and replicated twice to achieve the desired radius of curvature. It was subsequently successfully polished and tested. A recently awarded second phase to the AMTD project will develop larger mirrors to demonstrate the lateral scaling of the deep core mirror technology. Another key development was rapid modeling for the mirror. One model focused on generating optical and structural model results in minutes instead of months. Many variables could be accounted for regarding the core, face plate and back structure details. A portion of a spacecraft model was also developed. The spacecraft model incorporated direct integration to transform optical path difference to Point Spread Function (PSF) and between PSF to modulation transfer function. The second phase to the project will take the results of the rapid mirror modeler and integrate them into the rapid spacecraft modeler.

  1. Observational physics of mirror world

    NASA Technical Reports Server (NTRS)

    Khlopov, M. YA.; Beskin, G. M.; Bochkarev, N. E.; Pustilnik, L. A.; Pustilnik, S. A.

    1989-01-01

    The existence of the whole world of shadow particles, interacting with each other and having no mutual interactions with ordinary particles except gravity is a specific feature of modern superstring models, being considered as models of the theory of everything. The presence of shadow particles is the necessary condition in the superstring models, providing compensation of the asymmetry of left and right chirality states of ordinary particles. If compactification of additional dimensions retains the symmetry of left and right states, shadow world turns to be the mirror one, with particles and fields having properties strictly symmetrical to the ones of corresponding ordinary particles and fields. Owing to the strict symmetry of physical laws for ordinary and mirror particles, the analysis of cosmological evolution of mirror matter provides rather definite conclusions on possible effects of mirror particles in the universe. A general qualitative discussion of possible astronomical impact of mirror matter is given, in order to make as wide as possible astronomical observational searches for the effects of mirror world, being the unique way to test the existence of mirror partners of ordinary particles in the Nature.

  2. Kodak AMSD Mirror Development Program

    NASA Technical Reports Server (NTRS)

    Matthews, Gary; Dahl, Roger; Barrett, David; Bottom, John; Russell, Kevin (Technical Monitor)

    2002-01-01

    The Advanced Mirror System Demonstration Program is developing minor technology for the next generation optical systems. Many of these systems will require extremely lightweight and stable optics due to the overall size of the primary mirror. These segmented, deployable systems require new technology that AMSD is developing. The on-going AMSD program is a critical enabler for Next Generation Space Telescope (NGST) which will start in 2002. The status of Kodak's AMSD mirror and future plans will be discussed with respect to the NGST program.

  3. JWST NIRCam flight mirror assemblies

    NASA Astrophysics Data System (ADS)

    Mammini, Paul V.; Holmes, Howard C.; Huff, Lynn; Jacoby, Mike S.; Lopez, Frank

    2011-10-01

    The Near Infrared Camera (NIRCam) instrument for NASA's James Webb Space Telescope (JWST) has an optical prescription which includes numerous fold mirror assemblies. The instrument will operate at 35K after experiencing launch loads at ~293K. The optic mounts must accommodate all associated thermal and mechanical stresses, plus maintain exceptional optical quality during operation. Lockheed Martin Space Systems Company (LMSSC) conceived, designed, analyzed, assembled, tested, and integrated the mirror assemblies for the NIRCam instrument. This paper covers the design, analysis, assembly, and test of two of the instruments key fold mirrors.

  4. Fueling of tandem mirror reactors

    SciTech Connect

    Gorker, G.E.; Logan, B.G.

    1985-01-01

    This paper summarizes the fueling requirements for experimental and demonstration tandem mirror reactors (TMRs), reviews the status of conventional pellet injectors, and identifies some candidate accelerators that may be needed for fueling tandem mirror reactors. Characteristics and limitations of three types of accelerators are described; neutral beam injectors, electromagnetic rail guns, and laser beam drivers. Based on these characteristics and limitations, a computer module was developed for the Tandem Mirror Reactor Systems Code (TMRSC) to select the pellet injector/accelerator combination which most nearly satisfies the fueling requirements for a given machine design.

  5. Polarimetry with multiple mirror telescopes

    NASA Technical Reports Server (NTRS)

    West, S. C.

    1986-01-01

    The polarizations of multiple mirror telescopes are calculated using Mueller calculus. It is found that the Multiple Mirror Telescope (MMT) produces a constant depolarization that is a function of wavelength and independent of sky position. The efficiency and crosstalk are modeled and experimentally verified. The two- and four-mirror new generation telescopes are found to produce sinusoidal depolarization for which an accurate interpretation of the incident Stokes vector requires inverse matrix calculations. Finally, the depolarization of f/1 paraboloids is calculated and found to be less than 0.1 percent at 3000 A.

  6. Evanescent Wave Atomic Mirror

    NASA Astrophysics Data System (ADS)

    Ghezali, S.; Taleb, A.

    2008-09-01

    A research project at the "Laboratoire d'électronique quantique" consists in a theoretical study of the reflection and diffraction phenomena via an atomic mirror. This poster presents the principle of an atomic mirror. Many groups in the world have constructed this type of atom optics experiments such as in Paris-Orsay-Villetaneuse (France), Stanford-Gaithersburg (USA), Munich-Heidelberg (Germany), etc. A laser beam goes into a prism with an incidence bigger than the critical incidence. It undergoes a total reflection on the plane face of the prism and then exits. The transmitted resulting wave out of the prism is evanescent and repulsive as the frequency detuning of the laser beam compared to the atomic transition δ = ωL-ω0 is positive. The cold atomic sample interacts with this evanescent wave and undergoes one or more elastic bounces by passing into backward points in its trajectory because the atoms' kinetic energy (of the order of the μeV) is less than the maximum of the dipolar potential barrier ℏΩ2/Δ where Ω is the Rabi frequency [1]. In fact, the atoms are cooled and captured in a magneto-optical trap placed at a distance of the order of the cm above the prism surface. The dipolar potential with which interact the slow atoms is obtained for a two level atom in a case of a dipolar electric transition (D2 Rubidium transition at a wavelength of 780nm delivered by a Titane-Saphir laser between a fundamental state Jf = l/2 and an excited state Je = 3/2). This potential is corrected by an attractive Van der Waals term which varies as 1/z3 in the Lennard-Jones approximation (typical atomic distance of the order of λ0/2π where λ0 is the laser wavelength) and in 1/z4 if the distance between the atom and its image in the dielectric is big in front of λ0/2π. This last case is obtained in a quantum electrodynamic calculation by taking into account an orthornormal base [2]. We'll examine the role of spontaneous emission for which the rate is inversely

  7. Upgrade of surface profiler for x-ray mirror at SPring-8

    NASA Astrophysics Data System (ADS)

    Senba, Y.; Kishimoto, H.; Miura, T.; Ohashi, H.

    2014-09-01

    In beamlines at third-generation synchrotron radiation and X-ray free-electron-laser (XFEL) facilities, various mirrors are used as deflection, focusing, and collimating optics. The required specifications for the mirrors depend on their purpose. In recent years, high-precision aspheric mirrors and flat mirrors, with a figure error less than 10 nm are used as diffraction-limited focusing optics and deflection optics, respectively. The origins of the figure error are fabrication error, gravitational deformation, and clamping deformation. In the case of the bend mirror, figure error is also induced by the bender mechanism. The fabrication error is measured by a long trace profiler (LTP) [1] or by relative-angle determinable stitching interferometry (RADSI) [2] with special high frequency of 0.1-1/mm. Deformation caused by gravity, clamping, and bending should be measured under actual operating conditions because these deformations depend on the direction of the mirror surface and the direction of clamping and bending, respectively. In recent years, in-situ and atwavelength metrology techniques such as the Hartmann sensor, pencil beam, grating base and the speckle-effect-based technique, have been reported [3-6]. These methods are able to investigate the profile of the mirror under real conditions, including the effects of thermal bump; however, these techniques require X-rays and a long optical length to the detector. We attempted to upgrade the LTP at SPring-8 using autocollimators for the precise measurement of height profiles under conditions of both upward and horizontal reflection geometries. A portable Fizeau interferometer was installed for onsite measurement.

  8. Development of SiC ultra light mirror for large space telescope and for extremely huge ground based telescope

    NASA Astrophysics Data System (ADS)

    Ebizuka, Noboru; Dai, Yutang; Eto, Hiroaki; Lin, Weimin; Ebisuzaki, Toshikazu; Omori, Hitoshi; Handa, Thoshikazu; Takami, Hideki; Takahashi, Yoshiyuki

    2003-02-01

    Ultra lightweight mirrors of silicon carbide (SiC) are used for a large number of space telescopes, and SiC is also candidate as hopeful material for segmented mirrors of the next generation ground based telescopes from 20 to 100 m in diameter. However, an SiC mirror is difficult to shape because the material is very hard and brittle. We are developing an SiC mirror by means of an ultra-precision rotary grinding machine (800 mm in diameter) and the ELID (ELectrolytic In-process Dressing) grinding method. The method is suitable for fabrications of very hard materials, such as crystalline silicon and sapphire, ceramics, glasses, hard metals and so on. In this study, we present results of test fabrication for the SiC mirrors by means of ELID grinding method and evaluations of the profile deformation of the lightweight mirrors by using FEM simulation method.

  9. Tinbergen on mirror neurons

    PubMed Central

    Heyes, Cecilia

    2014-01-01

    Fifty years ago, Niko Tinbergen defined the scope of behavioural biology with his four problems: causation, ontogeny, survival value and evolution. About 20 years ago, there was another highly significant development in behavioural biology—the discovery of mirror neurons (MNs). Here, I use Tinbergen's original four problems (rather than the list that appears in textbooks) to highlight the differences between two prominent accounts of MNs, the genetic and associative accounts; to suggest that the latter provides the defeasible ‘best explanation’ for current data on the causation and ontogeny of MNs; and to argue that functional analysis, of the kind that Tinbergen identified somewhat misleadingly with studies of ‘survival value’, should be a high priority for future research. In this kind of functional analysis, system-level theories would assign MNs a small, but potentially important, role in the achievement of action understanding—or another social cognitive function—by a production line of interacting component processes. These theories would be tested by experimental intervention in human and non-human animal samples with carefully documented and controlled developmental histories. PMID:24778376

  10. Responder fast steering mirror

    NASA Astrophysics Data System (ADS)

    Bullard, Andrew; Shawki, Islam

    2013-09-01

    Raytheon Space and Airborne Systems (SAS) has designed, built and tested a 3.3-inch diameter fast steering mirror (FSM) for space application. This 2-axis FSM operates over a large angle (over 10 degree range), has a very high servo bandwidth (over 3.3 Khz closed loop bandwidth), has nanoradian-class noise, and is designed to support microradian class line of sight accuracy. The FSM maintains excellent performance over large temperature ranges (which includes wave front error) and has very high reliability with the help of fully redundant angle sensors and actuator circuits. The FSM is capable of achieving all its design requirements while also being reaction-compensated. The reaction compensation is achieved passively and does not need a separate control loop. The FSM has undergone various environmental testing which include exported forces and torques and thermal vacuum testing that support the FSM design claims. This paper presents the mechanical design and test results of the mechanism which satisfies the rigorous vacuum and space application requirements.

  11. Responder fast steering mirror

    NASA Astrophysics Data System (ADS)

    Bullard, Andrew; Shawki, Islam

    2013-10-01

    Raytheon Space and Airborne Systems (SAS) has designed, built and tested a 3.3-inch diameter fast steering mirror (FSM) for space application. This 2-axis FSM operates over a large angle (over 10 degree range), has a very high servo bandwidth (over 3.3 Khz closed loop bandwidth), has nanoradian-class noise, and is designed to support microradian class line of sight accuracy. The FSM maintains excellent performance over large temperature ranges (which includes wave front error) and has very high reliability with the help of fully redundant angle sensors and actuator circuits. The FSM is capable of achieving all its design requirements while also being reaction-compensated. The reaction compensation is achieved passively and does not need a separate control loop. The FSM has undergone various environmental testing which include exported forces and torques and thermal vacuum testing that support the FSM design claims. This paper presents the mechanical design and test results of the mechanism which satisfies the rigorous vacuum and space application requirements.

  12. New family of light beams and mirror shapes for future LIGO interferometers

    NASA Astrophysics Data System (ADS)

    Bondarescu, Mihai; Thorne, Kip S.

    2006-10-01

    Advanced LIGO’s present baseline design uses arm cavities with Gaussian light beams supported by spherical mirrors. Because Gaussian beams have large intensity gradients in regions of high intensity, they average somewhat poorly over fluctuating bumps and valleys on the mirror surfaces (thermal noise). Flat-topped light beams (mesa beams) are being considered as an alternative because they average over thermal noise more effectively. However, the proposed mesa beams are supported by nearly-flat mirrors, which experience a very serious tilt instability. In this paper we propose an alternative configuration in which mesa-shaped beams are supported by nearly-concentric spheres, which experience only a weak tilt instability. The tilt instability is analyzed for these mirrors in a companion paper by Savov and Vyatchanin. We also propose a one-parameter family of light beams and mirrors in which, as the parameter α varies continuously from 0 to π, the beams and supporting mirrors get deformed continuously from the nearly-flat-mirrored mesa configuration (FM) at α=0, to the nearly-concentric-mirrored mesa configuration (CM) at α=π. The FM and CM configurations at the endpoints are close to optically unstable, and as α moves away from 0 or π, the optical stability improves.

  13. Design and simulation of the surface shape control system for membrane mirror

    NASA Astrophysics Data System (ADS)

    Zhang, Gengsheng; Tang, Minxue

    2009-11-01

    The surface shape control is one of the key technologies for the manufacture of membrane mirror. This paper presents a design of membrane mirror's surface shape control system on the basis of fuzzy logic control. The system contains such function modules as surface shape design, surface shape control, surface shape analysis, and etc. The system functions are realized by using hybrid programming technology of Visual C# and MATLAB. The finite element method is adopted to simulate the surface shape control of membrane mirror. The finite element analysis model is established through ANSYS Parametric Design Language (APDL). ANSYS software kernel is called by the system in background running mode when doing the simulation. The controller is designed by means of controlling the sag of the mirror's central crosssection. The surface shape of the membrane mirror and its optical aberration are obtained by applying Zernike polynomial fitting. The analysis of surface shape control and the simulation of disturbance response are performed for a membrane mirror with 300mm aperture and F/2.7. The result of the simulation shows that by using the designed control system, the RMS wavefront error of the mirror can reach to 142λ (λ=632.8nm), which is consistent to the surface accuracy of the membrane mirror obtained by the large deformation theory of membrane under the same condition.

  14. Infrared/millimeter wave mirror array beam combiner design and analysis.

    PubMed

    Tian, Yi; Sun, Gang; Li, Fan; Yan, Hui; Zhang, Li; Li, Zhuo

    2014-06-20

    The design method of an infrared/millimeter wave mirror array type of beam combiner was investigated. The beam combiner was composed of a support plate, air gap, and mirror array. It had two advantages: one was that the size of the beam combiner could be extended by splicing more mirrors; the other was that the millimeter wave passband could be tuned by adjusting the thickness of the air gap. The millimeter wave and infrared structure was designed by using transmission line theory and optimized by a simplex Nelder-Mead method. In order to analyze the influence of deformation on performance, the mechanical characteristics of the mirrors and support plate were analyzed by the finite element method. The relationship between the millimeter wave transmission characteristics and the air gap was also analyzed by transmission line theory. The scattered field caused by pillars was computed by the multilevel fast multipole method. In addition, the effect of edge diffraction on the near field uniformity was analyzed by the aperture field integration method. In order to validate the mirror array splicing principle and the infrared imaging performance, a prototype of the mirror array was fabricated and tested. Finally, the infrared images reflected by the mirror array were obtained and analyzed. The simulation and experiment results validated the feasibility of the mirror array beam combiner. PMID:24979417

  15. Optimization analysis of primary mirror in large aperture telescope based on workbench

    NASA Astrophysics Data System (ADS)

    Feng, Zhengsen; Wang, Guomin

    2015-10-01

    With the diameter increasing for large aperture telescope primary mirror, the gravity caused by the increased of surface size will directly affect the quality of optical imaging, the adjustment of large aperture primary mirror will be frequent according to the requirement of observation. As the angle and the azimuth's transformation of primary mirror influences the surface shape accuracy immediately, the rational design of the primary mirror supporting structure is of crucial importance. Now the general method is to use ANSYS APDL programming, which is inconvenient and complex to fit for the different components, the calculation require much time and the analysis is lack of efficient. Taking the diameter of 1.12 m telescope primary mirror as the research objection, the paper combine the actual design parameters of SONG telescope, respectively using ANSYS WORKBENCH to employ the primary mirror axial and lateral support model in finite element method, the optimal solution is obtained by optimization design and the change rule of mirror surface deformation under inclined condition is studied. The optimization results according with the requirements of the primary mirror comprehensive error proves that the optimization analysis method is available and applicable.

  16. New family of light beams and mirror shapes for future LIGO interferometers

    SciTech Connect

    Bondarescu, Mihai; Thorne, Kip S.

    2006-10-15

    Advanced LIGO's present baseline design uses arm cavities with Gaussian light beams supported by spherical mirrors. Because Gaussian beams have large intensity gradients in regions of high intensity, they average somewhat poorly over fluctuating bumps and valleys on the mirror surfaces (thermal noise). Flat-topped light beams (mesa beams) are being considered as an alternative because they average over thermal noise more effectively. However, the proposed mesa beams are supported by nearly-flat mirrors, which experience a very serious tilt instability. In this paper we propose an alternative configuration in which mesa-shaped beams are supported by nearly-concentric spheres, which experience only a weak tilt instability. The tilt instability is analyzed for these mirrors in a companion paper by Savov and Vyatchanin. We also propose a one-parameter family of light beams and mirrors in which, as the parameter {alpha} varies continuously from 0 to {pi}, the beams and supporting mirrors get deformed continuously from the nearly-flat-mirrored mesa configuration (FM) at {alpha}=0, to the nearly-concentric-mirrored mesa configuration (CM) at {alpha}={pi}. The FM and CM configurations at the endpoints are close to optically unstable, and as {alpha} moves away from 0 or {pi}, the optical stability improves.

  17. The magic of relay mirrors

    NASA Astrophysics Data System (ADS)

    Duff, Edward A.; Washburn, Donald C.

    2004-09-01

    Laser weapon systems would be significantly enhanced with the addition of high altitude or space-borne relay mirrors. Such mirrors, operating alone with a directed energy source, or many in a series fashion, can be shown to effectively move the laser source to the last, so-called fighting mirror. This "magically" reduces the range to target and offers to enhance the performance of directed energy systems like the Airborne Laser and even ground-based or ship-based lasers. Recent development of high altitude airships will be shown to provide stationary positions for such relay mirrors thereby enabling many new and important applications for laser weapons. The technical challenges to achieve this capability are discussed.

  18. JWST Primary Mirror Installation Complete

    NASA Video Gallery

    Completing the assembly of the primary mirror, which took place at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, is a significant milestone and the culmination of over a decade of desi...

  19. Paper like cholesteric interferential mirror.

    PubMed

    Petriashvili, Gia; Japaridze, Kokhta; Devadze, Lali; Zurabishvili, Cisana; Sepashvili, Nino; Ponjavidze, Nino; De Santo, Maria P; Matranga, Mario A; Hamdi, Ridha; Ciuchi, Federica; Barberi, Riccardo

    2013-09-01

    A new type of flexible cholesteric liquid crystal mirror is presented. The simple and effective method for the deposition of a cholesteric mixture on a paper substrate and the particular design of the device give a homogeneous alignment of the cholesteric texture providing mirrors with an intense and uniform light reflectance. A desired polarization state for the reflected light, linear or circular, can be easily obtained varying the thickness and optical anisotropy of the polymer cover film. By using non-azobenzene based photosensitive materials a permanent array of RGB mirrors with high reflectivity can be obtained on the same device. Paper like reflective mirrors are versatile and they can find applications in reflective displays, adaptive optics, UV detectors and dosimeters, information recording, medicine and IR converters. PMID:24103954

  20. JWST Secondary Mirror Deploy Timelapse

    NASA Video Gallery

    Setting up NASA's James Webb Space Telescope's secondary mirror in space will require special arms that resemble a tripod that was recently demonstrated in a NASA cleanroom. TRT: 1:25 / Credit: NAS...