Design and Development of Bimorph Deformable Mirrors for Defocus Correction
|
|
- Adelia Alberta Anderson
- 5 years ago
- Views:
Transcription
1 Design and Development of Bimorph Deformable Mirrors for Defocus Correction Kavita Rawal, Vijayeta Gambhir and D.P Ghai Laser Science and Technology Center, Metcalfe House, Old sectt, Delhi , India. ABSTRACT A single element Bimorph Deformable mirror 1, 2 was designed and fabricated for defocus correction of the laser wavefront. The design was optimized in terms of mirror substrate material and thickness of the substrate, dimensions and piezoelectric properties of the PZT discs. The series bimorph deformable mirror discussed in this paper consists of 2.5mm thick, 50mm diameter silicon mirror. The PZT used for the design had d 33 coefficient of pc/n. The surface deformation and Radius of curvature of the DM was studied by setting up a Michelson Interferometer in the laboratory and also with a commercial Shack Hartmann wavefront sensor. The maximum surface deformation of 5 microns was recorded at the actuation voltage of ± 400volts. The frequency response of the bimorph deformable mirror was also studied. The deformable mirror shows the first mechanical resonance at 900Hz. Keywords: Adaptive optics, wavefront aberrations, deformable mirrors, bimorph, unimorph, PZT. 1. INTRODUCTION Although bimorph mirrors were envisaged a long time ago 3, 4 (Kokorowski 1979; Steinhaus and Lipson 1979), the actual use of a bimorph mirror in adaptive optics was first demonstrated in 1994 in a system developed at the University of Hawaii for astronomical applications (Roddier et al. 1994) A bimorph mirror now equips the PUEO user AO system of the Canada-France Hawaii Telescope (Lai et al. 1995). Bimorph mirrors are also under test for the SUBARU AO system (Takami et al, 1995) and for the Anglo-Australian Telescope AO system (Bryant et al. 1995). The performance requirements of deformable mirrors vary according to applications, which include high energy laser focusing, compensated imagery through atmospheric turbulence, and laser cavity control. Compared to astronomical applications, requirement related to defense applications are often more demanding. In the recent past a lot of progress has taken place in the field of adaptive optics which can be attributed to advancements in electronics, processing, control systems, high speed sensors but it is also associated with more complex design of deformable mirrors with a large number of sub apertures or actuators. Astronomical adaptive optics systems with a large number of elements have been fabricated. These systems are inherently expensive and complex to build. However the largest low-order phase distortions are rather slow in comparison with higher order ones, and it is cost effective to use two adaptive mirrors one a Bimorph for lower order is modal mirror with a large range of surface deformations and a second stacked actuator continuous or segmented face sheet mirror for higher order aberrations. Bimorph deformable mirrors are basically Laplacian correctors 5, 6 are becoming popular because of their low cost and ease of fabrication and do not involve complexity of design. 2. THEORY A bimorph mirror consists of two piezoelectric wafers 7, 8 which are bonded together and are oppositely polarized (parallel to their axes), this in turn is bonded to quartz or a silicon substrate. There is a common electrode between the substrate and the PZT, and a set of discrete electrodes on the rear face of PZT to which control voltages can be applied. The front face of the substrate has a reflective coating. When voltage is applied across two ends of the piezo disc, one-wafer contracts and the opposite wafer expands, which produces a local bending. The local curvature being
2 proportional to voltage. A tricky characteristic of bimorph DMs is that they are controlled not in surface shape, but in surface curvature and are called curvature mirrors 9,10 it tends to expand in the radial direction but glued interface of the substrate opposes this expansion. This results in the bending of the substrate, thereby, generating a defocus effect or forming a convex or concave curvature depending on the polarity of the applied voltage. The deformation of the mirror surface is typically a few microns, and a wide range of wavefront profiles can be generated by giving different combination of voltages and these can be interpreted in terms of various atmospheric aberrations as well as aberrations in the laser due to medium inhomogeneites like defocus, astigmatism, coma, spherical aberration etc. The bimorph deformable mirror 11 can be treated as a thin plate and the deformation can be interpreted according to the bending of thin plates therefore when a voltage applied across the thin dimension of the plate causes an expansion or contraction in the plane of the plate and bends the substrate in a manner analogous to a bimetallic strip. The relative change in length induced on an electrode of size L is given by L/L = V d 31 / t (1) Where d 31 is the transverse piezoelectric coefficient and t is the thickness of the wafer. Neglecting the stiffness of the wafers and three-dimensional effects, and assuming the piezoceramic wafer thickness to be small as compared to the substrate, the curvature produced is given approximately by: R=t 2 /2V d 31 (2) Where d 31 is the transverse piezoceramic strain constant and t is the glass plate thickness. V is the applied voltage and, as can be seen from equation (2), that the local curvature is proportional to the locally applied voltage. For a spherical deformation over the diameter d, the bimorph sensitivity Sb expressed as the ratio of stroke/voltage is: S b = d 2 /8 R V =( d 2 /4t 2 ) d 31 (3) The static equation of state for an ideal bimorph mirror has the form (Kokorowski 1979; Roddier 1988) δ 2 (δ 2 W+ AV) =0 (4) Where δ 2 denotes the two-dimensional Laplacian, W (x, y) is the mirror surface deformation, V (x, y) is the voltage distribution on the wafer, and A=8d 31 /t 2. The equilibrium is reached when the mirror surface is the solution of a poisson equation with appropriate boundary conditions. Radial tilts at the edge provide the boundary conditions required to solve the Poisson equation. A simple way to control these tilts is to use an extra ring of electrodes and to limit the pupil to the inner part of their surfaces (Jagourel et al. 1990). Besides this displacement, the applied voltage causes opposite changes of the thickness of each wafer (Kokorowski 1979). Even if this effect cancels for the entire bimorph 12 it still produces a displacement of the top and bottom surfaces, which is added to the displacement caused by bending. From equation (4) the deformation due to thickness changes over an electrode may be written Wt (x, y) = - b V (x, y) d 31. This effect can be compared with the pure bending deformation over an electrode of diameter d given by equation (3). These effects are opposite and the resulting displacement is locally zero when the wafer diameter d becomes of the order of the thickness. Since the ratio of the diameter of the whole wafer to the thickness is limited by polishing considerations, the number of electrodes is limited by the bimorph diameter to thickness ratio. Typically a few tens of electrodes are used. Hence, bimorph mirrors are best suited for lower order compensation systems. Owing to the k -2 spectrum dependence bimorph mirrors have a sufficient stroke at low spatial frequencies to compensate for turbulence induced tip/tilt errors. 3. DESIGN AND FABRICATION Although the Bimorph deformable mirrors are now commercially available and being used in various prestigious projects related to astronomy, adaptive optics and for laser source correction. As a step towards indigenous development, we have chosen to develop single element series type bimorph deformable mirror design for defocus correction as well as optimizing our design in terms of substrate material, diameter, thickness and also for PZT d 33
3 coefficient, diameter, thickness and mounting procedures. The silicon facesheet material is selected as the optimum choice based upon our theoretical studies on substrate material selection of deformable mirror facesheets for adaptive optics. The silicon substrates of 1, 2, 3 diameter and each of 3.5mm, 2.5mm and 1.5mm thickness were acquired and The PZT discs of different d 33 in the range of 400 pc/n to 650 pc/n and of diameters of 9mm, 20mm, 22mm were used to facilitate our design. To begin with all the optically polished silicon substrate surfaces were monitored on ZYGO for initial surface flatness with and without mounting so as to ensure that there is no deformation induced due to the mechanical mounts of the deformable mirror. We have selected to fabricate the series type bimorph deformable mirror as shown in figure (1). In this configuration two PZT discs with conductive coatings on both the surfaces were glued together in series with the conducting silver epoxy which should not expand or contract upon hardening and cured in the oven for 2-3 hours at 80 degree Celsius, till the adhesive had completely hardened. These cured bimorph discs were then adhered to the Silicon substrates of thickness varying from 1.5mm to 3.5mm and diameters of 25, 50 and 76mm with the conducting silver epoxy, and again kept in the oven for 2-3 hours at 80 degree Celsius and then allowed to cool to remove the residual thermal deformations. In the case of unimorph deformable mirror instead of two PZT discs only a single disc was used and same procedure was followed for its fabrication too. The Electrical connections were then made to the electrodes for its performance evaluation.the mechanical mounting of a bimorph DM is delicate in the sense that on one hand, it must be left to deform, on the other hand it must be fixed in the optical system. The mechanical mounts were designed and fabricated for mounting the deformable mirrors of different diameters. Figure (1): Morphology of series type Bimorph deformable mirror 4. PERFORMANCE EVALUATION The static as well as dynamic characteristics of the mirrors were studied. The surface profiles of all the mirror substrates were observed on Zygo for its initial surface flatness etc. A Michaelson Interferometer was setup in the laboratory to study the performance of the bimorph mirrors for the deformation produced as shown figure (2). We have used He-Ne (0.632microns) laser for these measurements. The deformation was estimated from the displacement of the interference fringes at the center of the pattern when the voltage was varied from 400 volts to +400 volts shown in figure (3) as one fringe shift corresponds to half the wavelength of the laser beam used. The deformation produced by these deformable mirrors was also evaluated on class 2D Shack Hartmann Wave front sensor set up shown in figure (4), on which the peak to valley surface deformation has been recorded as the 3D phase plot as given in figure (5). The results from both Michelson setup as well as SHWFS were in close agreement. The frequency response of the bimorph DM was also studied by monitoring the variation of the amplitude at the output of the silicon photo detector on varying the frequency of the signal at a constant voltage given to drive the bimorph deformable mirror. A number of prototypes of such bimorph and unimorph deformable mirrors were
4 fabricated for different dimensions of the mirror substrate and PZT discs parameters. Finally each of them was tested for its deformation and frequency response. Figure (2): Experimental setup for the evaluation of bimorph DM. Figure (3): Interferograms of single actuator BDM.
5 Figure (4): Testing of Bimorph deformable mirror on a Shack-Hartmann wave front sensor Figure (5): 3D Phase plot for Bimorph dm 50mm dia, 2.5mm thick at 400volts as Recorded on SHWFS. 5. RESULTS AND DISCUSSION The results of all the experimental measurements for the surface deformation have recorded. The effects of the variation of parameters and dimensions of the mirror substrate & PZT discs are compared and the results are shown in the graphical plots as given in figure (6,7,8,9,10,). The radius of curvature of the bimorph DM was also calculated and its variation with stroke is plotted in figure (11). The frequency response of the Bimorph deformable mirror for
6 the silicon substrate diameter of 50mm and thickness 2.5mm has been shown in the figure (12). This deformable mirror exhibits a bandwidth of about 500 Hz and the first mechanical resonance occurred at around 900Hz. The maximum surface deformation of 5 microns was recorded for the actuation voltage of 400volts to + 400volts The comparative analysis of all these experimental data indicates that for a fixed substrate diameter, decreasing the substrate thickness results in an increase of surface deformation and increasing the diameter of the PZT disc for the same diameter and thickness of the substrate also leads to an increase in the stroke or the deformation. Also with the increase in the diameter of the substrate, keeping all other parameters same, deformation of the mirror increases. The deformation measured was almost 1.5 times to two times more in the case of bimorph as compared to a unimorph. When increased d 33 value PZT material was used for the study, it resulted in increased deformation at the same driving voltages. This is in accordance with the theoretical relationship for the calculation of deformation in Bimorph Deformable mirrors. The experimental results are in accordance with the theory discussed above. The success of the single element Bimorph deformable mirror has encouraged us to go for multi-element bimorph deformable mirror development for producing and interpreting other higher order aberrations like astigmatism, coma, etc, and the work in this direction is in progress. Figure (6): The variation of surface deformation with dc voltage.
7 Figure (7): Surface deformation versus substrate thickness for 25.4mm mirror diameter and PZT dia of 9mm for bimorph and unimorph deformable mirror. Figure (8): Surface deformation versus substrate thickness for 50mm mirror diameter and PZT dia of 9mm for bimorph and unimorph deformable mirror.
8 Figure (9): Surface deformation versus thickness for 50mm substrate diameter and PZT diameter of 20mm for bimorph and unimorph deformable mirror. Figure (10): Surface deformation versus thickness for 25.4mm substrate diameter and PZT diameter of 20mm for bimorph and unimorph deformable mirror
9 Figure (11): Variation of the Radius of curvature versus stroke or deformation. Figure (12): Frequency response of 50mm diameters, 2.5mm thick bimorph deformable mirror.
10 6. CONCLUSION The performance of the DM strongly depends upon the type of mirror substrate, its thickness, diameter and initial surface flatness. It also depends on PZT disc dimension and its piezoelectric coefficient. The PZT disc should be thick enough to generate required localized bending force. However, a thicker plate demands a higher voltage to be applied across it for required expansion. The bonding material should be such that it does not under go shrinkage after application. The coefficient of thermal expansion of the mirror material and the PZT must closely match. However we can not go on reducing the thickness of the substrate or increase its diameter as the ratio has to be maintained due to polishing considerations and reducing the thickness of the mirror substrate below one mm will introduce some distortions or initial curvature on mounting so a trade-off needs to be established between these parameters for an optimum design of deformable mirrors. ACKNOWLEDGEMENT We wish to express our sincere gratitude to Shri K. S. Jindal, Director, LASTEC, Delhi for his constant support and encouragement. We also thank Dr. C. P. Rana and Dr. O. P. Thakur, SSPL, Delhi for providing us the piezoelectric discs to carry out this work. REFERENCES: 1. Journal Article: M.A.Ealey et.al, Proc SPIE 2201,680 (1994). 2. Journal Article: J.Christopher Dainty et.al,applied Optics, Vol.37,No21,4663(1998). 3. Journal Article: N.T. Adelman,,Applied optics,16,3075(1977). 4. Spherical mirrors for piezoelectrically controlled curvature N.T Adelman. Applied Optics No. 16, 3075(1977). 5. Semi passive bimorph flexible mirrors for atmospheric adaptive optics applications A. Kudyashov, and V Shmalhausen, Optical Engineering, No.35, 3064 (1996). 6. Bimorph deformable mirror design, S. Lipson, E. Ribak, c. Schwartz, proc. SPIE,vol 2201,703(1994). 7. Bimorph PZT active mirror, F.F Forbes, Proc. SPIE, vol 1114, 146(1989). 8. Bimorph adaptive mirrors and curvature sensing, C Schwartz, E Ribak and S, Lipson, JOSA A 11(2),895(1994). 9. Experimental studies of a deformable adaptive optical system, E Pearson, S. Hansen, JOSA No. 67, 325(1977). 10. Analysis of adaptive optical elements made from piezoelectric bimorphs, S A Kokorowski, JOSA No. 69,181(1979). 11. Controllable bimorph optics and the principles according to which they can be developed further, A G Safronov, J. Opt. Technol No. 65,4,(1996). 12. Comparison of deformability between multilayered deformable mirrors with a monomorph or bimorph actuator, O Ikeda and T. Sato, apllied Optics, No (1986).
UNIMORPH DEFORMABLE MIRROR FOR TELESCOPES AND LASER APPLICATIONS IN SPACE
UNIMORPH DEFORMABLE MIRROR FOR TELESCOPES AND LASER APPLICATIONS IN SPACE S. Verpoort and U. Wittrock Photonics Laboratory, Münster University of Applied Sciences, Stegerwaldstrasse 39, 48565 Steinfurt,
More informationNovel Unimorph Deformable Mirror for Space Applications
Novel Unimorph Deformable Mirror for Space Applications Sven Verpoort, Peter Rausch, and Ulrich Wittrock Photonics Laboratory, Münster University of Applied Sciences Stegerwaldstraße 39, 48565 Steinfurt,
More informationROTATIONAL SHEARING INTERFEROMATER. Introduction. The Interferometer. L. Yeswanth, Optics Group, IIA, Bangalore
ROTATIONAL SHEARING INTERFEROMATER L. Yeswanth, Optics Group, IIA, Bangalore Introduction A rotational shearing interferometer is a modification of the Michelson s interferometer to obtain the spatial
More informationInternational Journal of Scientific & Engineering Research, Volume 4, Issue 7, July ISSN
International Journal of Scientific & Engineering Research, Volume 4, Issue 7, July-2013 96 Performance and Evaluation of Interferometric based Wavefront Sensors M.Mohamed Ismail1, M.Mohamed Sathik2 Research
More informationWavefront Sensing using Polarization Shearing Interferometer. A report on the work done for my Ph.D. J.P.Lancelot
Wavefront Sensing using Polarization Shearing Interferometer A report on the work done for my Ph.D J.P.Lancelot CONTENTS 1. Introduction 2. Imaging Through Atmospheric turbulence 2.1 The statistics of
More information대기외란보정을위한단일연속변형거울에관한연구 A Study on a Single Continuous Deformable Mirror for Correction of Atmospheric Disturbance
한국정밀공학회지제 35 권제 10 호 pp. 943-949 October 2018 / 943 J. Korean Soc. Precis. Eng., Vol. 35, No. 10, pp. 943-949 https://doi.org/10.7736/kspe.2018.35.10.943 ISSN 1225-9071 (Print) / 2287-8769 (Online) 특집
More informationUsing 50-mm electrostatic membrane deformable mirror in astronomical adaptive optics
Using 50-mm electrostatic membrane deformable mirror in astronomical adaptive optics Andrei Tokovinin a, Sandrine Thomas a, Gleb Vdovin b a Cerro Tololo Inter-American Observatory, Casilla 603, La Serena,
More informationVACUUM SUPPORT FOR A LARGE INTERFEROMETRIC REFERENCE SURFACE
VACUUM SUPPORT FOR A LARGE INTERFEROMETRIC REFERENCE SURFACE Masaki Hosoda, Robert E. Parks, and James H. Burge College of Optical Sciences University of Arizona Tucson, Arizona 85721 OVERVIEW This paper
More informationINTRODUCTION TO PIEZO TRANSDUCERS
PIEZO SYSTEMS, INC. 65 Tower Office Park Woburn, MA 01801 USA Tel: 781 933 4850 Fax: 781 933 4743 email: sales@piezo.com Find Search for a product or category HOME PRODUCTS CUSTOM OEM CATALOG TECHNICAL
More informationPolarization Shearing Interferometer (PSI) Based Wavefront Sensor for Adaptive Optics Application. A.K.Saxena and J.P.Lancelot
Polarization Shearing Interferometer (PSI) Based Wavefront Sensor for Adaptive Optics Application A.K.Saxena and J.P.Lancelot Adaptive Optics A Closed loop Optical system to compensate atmospheric turbulence
More informationNon-Linear Finite Element Modeling of THUNDER Piezoelectric Actuators
Non-Linear Finite Element Modeling of THUNDER Piezoelectric Actuators Barmac K. Taleghani 1, Joel F. Campbell 2 1 Army Research Laboratory, Vehicle Technology Center, MS 230 NASA Langley Research Center,
More informationIMECE SINGLE CRYSTAL PIEZOELECTRIC ACTUATORS FOR ADVANCED DEFORMABLE MIRRORS
Proceedings of IMECE04 2004 ASME International Mechanical Engineering Congress and Exposition November 13-20, 2004, Anaheim, California USA IMECE2004-60504 SINGLE CRYSTAL PIEZOELECTRIC ACTUATORS FOR ADVANCED
More informationFigure testing of 300 mm Zerodur mirrors at cryogenic temperatures
Figure testing of 300 mm Zerodur mirrors at cryogenic temperatures J. W. Baer, W. P. Lotz Ball Aerospace & Technologies Corp. PO Box 1062 Boulder, CO 80306 Keywords: mirrors, figure testing, cryogenic,
More informationWave-front generation of Zernike polynomial modes with a micromachined membrane deformable mirror
Wave-front generation of Zernike polynomial modes with a micromachined membrane deformable mirror Lijun Zhu, Pang-Chen Sun, Dirk-Uwe Bartsch, William R. Freeman, and Yeshaiahu Fainman We investigate the
More informationA piezoelectric deformable mirror for intra-cavity laser adaptive optics
A piezoelectric deformable mirror for intra-cavity laser adaptive optics Craig S. Long* a, Philip W. Loveday a and Andrew Forbes b,c a Sensor Science & Technology, CSIR Material Science and Manufacturing,
More information1 Naval Research Laboratory Remote Sensing Division, Code Aberdeen Ave SE Kirtland AFB, NM 87117
Carbon Fiber Reinforced Polymer (CFRP) Telescope Program at the Naval Research Laboratory Sergio R. Restaino 1, Ty Martinez 1, Jonathan R. Andrews 1, Christopher C. Wilcox 1, S. Teare 2, Robert Romeo 3,
More informationMore Optical Telescopes
More Optical Telescopes There are some standard reflecting telescope designs used today All have the common feature of light entering a tube and hitting a primary mirror, from which light is reflected
More informationThermal Analysis on Hex Placement Patterns of the Gemini Primary Mirrors. M. K. Cho Gemini Telescopes Project, 950 N. Cherry Ave.
Thermal Analysis on Hex Placement Patterns of the Gemini Primary Mirrors M. K. Cho Gemini Telescopes Project, 950 N. Cherry Ave., Tucson AZ 85719 W. R. Powell Corning Incorporated, Science & Technology
More informationLAB DEMONSTRATION OF INTERFEROMETRIC
LAB DEMONSTRATION OF INTERFEROMETRIC MEASUREMENT USING A TEST PLATE AND CGH Presented to: Larry Stepp Eric Hansen The Association of Universities for Research in Astronomy, Inc. Tucson, AZ, 85726 Prepared
More informationWavefront Correction of Model-based Sensorless Adaptive Optics System
Wavefront Correction of Model-based Sensorless Adaptive Optics System Huizhen Yang 1*, Jian Wu 2 1. School of Electronic Engineering, Huaihai Institute of Technology, Lianyungang, China 222005; 2. School
More informationThe IPIE Adaptive Optical System Application For LEO Observations
The IPIE Adaptive Optical System Application For LEO Observations Eu. Grishin (1), V. Shargorodsky (1), P. Inshin (2), V. Vygon (1) and M. Sadovnikov (1) (1) Open Joint Stock Company Research-and-Production
More informationAdaptive Optics for the Giant Magellan Telescope. Marcos van Dam Flat Wavefronts, Christchurch, New Zealand
Adaptive Optics for the Giant Magellan Telescope Marcos van Dam Flat Wavefronts, Christchurch, New Zealand How big is your telescope? 15-cm refractor at Townsend Observatory. Talk outline Introduction
More informationHomogeneity of optical glass
1 Version ebruary 2016 Introduction SCHOTT offers machined optical glasses with homogeneities up to H5 quality. I-Line glasses can even be offered in higher homogeneities. The achievable homogeneity depends
More informationPiezoelectric Resonators ME 2082
Piezoelectric Resonators ME 2082 Introduction K T : relative dielectric constant of the material ε o : relative permittivity of free space (8.854*10-12 F/m) h: distance between electrodes (m - material
More informationAdaptive Optics Overview. Presentation to Summer School 2003, August 10 Jerry Nelson
Adaptive Optics Overview Presentation to Summer School 2003, August 10 Jerry Nelson Outline The Center for Adaptive Optics CfAO Organization and Mission Thematic structure Main thrust of summer school:pragmatic
More informationDesign and Optimization of An All Optically Driven Phase Correction MEMS Device using FEA
Presented at the COMSOL Conference 2009 Boston Design and Optimization of An All Optically Driven Phase Correction MEMS Device using FEA V. Mathur, K.Anglin, V.S. Prasher, K.Tremkoa, S.R. Vangala, X. Qian,
More informationDeformable mirror fitting error by correcting the segmented wavefronts
1st AO4ELT conference, 06008 (2010) DOI:10.1051/ao4elt/201006008 Owned by the authors, published by EDP Sciences, 2010 Deformable mirror fitting error by correcting the segmented wavefronts Natalia Yaitskova
More informationPupil matching of Zernike aberrations
Pupil matching of Zernike aberrations C. E. Leroux, A. Tzschachmann, and J. C. Dainty Applied Optics Group, School of Physics, National University of Ireland, Galway charleleroux@yahoo.fr Abstract: The
More informationNUMERICAL MODELLING OF A THIN DEFORMABLE MIRROR FOR LASER BEAM CONTROL
Seventh South African Conference on Computational and Applied Mechanics SACAM Pretoria, 3 January 2 c SACAM NUMERICAL MODELLING OF A THIN DEFORMABLE MIRROR FOR LASER BEAM CONTROL Craig S. Long,, Philip
More informationNext generation of piezo deformable mirrors
Next generation of piezo deformable mirrors Hubert Pagès, Tania Antonini, Tarik Aribi, Arnaud Bastard, Emmanuel Beaufort, Grégory Chauveau, Raphaël Cousty, Gabrielle Dutey, Catherine Grèzes-Besset, Denis
More informationNB: from now on we concentrate on seeing, as scintillation for large telescopes is unimportant
b) intensity changes: scintillation!i/i on the ground is proportional to h!", i.e. # h e -h/h this function has maximum at h = H = 8.5 km! scintillation comes mostly from high layers! seeing and scintillation
More informationPart 1 - Basic Interferometers for Optical Testing
Part 1 - Basic Interferometers for Optical Testing Two Beam Interference Fizeau and Twyman-Green interferometers Basic techniques for testing flat and spherical surfaces Mach-Zehnder Zehnder,, Scatterplate
More informationMCE603: Interfacing and Control of Mechatronic Systems
MCE603: Interfacing and Control of Mechatronic Systems Chapter 7: Actuators and Sensors Topic 7d: Piezoelectric Actuators. Reference: Various articles. Cleveland State University Mechanical Engineering
More informationOOFELIE::Multiphysics 2014
OOFELIE::Multiphysics 2014 INDUSTRIAL MULTIPHYSICS DESIGN FOR OPTICAL DEVICES INTRODUCTION 2 High precision opto-mechanics A VERY HIGH ACCURACY IN THE PRODUCTION OF MIRRORS AND LENSES IS NOW VERY OFTEN
More informationOptical Interface for MSC.Nastran
Optical Interface for MSC.Nastran Victor Genberg, Keith Doyle, Gregory Michels Sigmadyne, Inc., 803 West Ave, Rochester, NY 14611 genberg@sigmadyne.com Abstract Thermal and structural output from MSC.Nastran
More informationAOL Spring Wavefront Sensing. Figure 1: Principle of operation of the Shack-Hartmann wavefront sensor
AOL Spring Wavefront Sensing The Shack Hartmann Wavefront Sensor system provides accurate, high-speed measurements of the wavefront shape and intensity distribution of beams by analyzing the location and
More information1. INTRODUCTION ABSTRACT
Simulations of E-ELT telescope effects on AO system performance Miska Le Louarn* a, Pierre-Yves Madec a, Enrico Marchetti a, Henri Bonnet a, Michael Esselborn a a ESO, Karl Schwarzschild strasse 2, 85748,
More informationAdaptive Optics and OIR Interferometry
Outline and OIR Interferometry Astro 6525 Fall 2015 November 17 2015 Wavefront Sensing Control Systems Error Terms and Limitations Laser Guide Stars GLAO/MCAO/MOAO 2 Optical vs Radio Telescopes Fraunhofer
More informationFinal Project Report. Contract/Grant Title: Development of High-Fill-Factor Large-Aperture Micromirrors for Agile Optical Phased Arrays
Final Project Report Contract/Grant Title: Development of High-Fill-Factor Large-Aperture Micromirrors for Agile Optical Phased Arrays Contract/Grant #: FA9550-08-1-0292 Reporting Period: 1 June 2008 to
More informationAtmospheric dispersion correction for the Subaru AO system
Atmospheric dispersion correction for the Subaru AO system Sebastian Egner a, Yuji Ikeda b, Makoto Watanabe c,y.hayano a,t.golota a, M. Hattori a,m.ito a,y.minowa a,s.oya a,y.saito a,h.takami a,m.iye d
More informationAdaptive Optics and its Application to Astronomy
Adaptive Optics and its Application to Astronomy Francois J. RODDIER Institute for Astronomy, University of Hawaii, 2680 Woodlawn Dr, Honolulu, HI 96822 USA (Received November 11, 1998) Adaptive optics
More informationOpto-Mechanical I/F for ANSYS
Opto-Mechanical I/F for ANSYS Victor Genberg, Gregory Michels, Keith Doyle Sigmadyne, Inc. Abstract Thermal and structural output from ANSYS is not in a form useful for optical analysis software. Temperatures,
More informationWavefront Estimation and Control: Ground
Wavefront Estimation and Control: Ground Donald Gavel UCO/Lick Observatory Laboratory for Adaptive Optics Michelson Summer School High Contrast Imaging in Astrophysics July 21, 2004 Outline Purpose and
More informationAnalysis of Shane Telescope Aberration and After Collimation
UCRL-ID- 133548 Analysis of Shane Telescope Aberration and After Collimation Before Don Gavel January 26,1999 This is an informal report intended primarily for internal or limited external distribution.
More informationMetrology and Sensing
Metrology and Sensing Lecture 5: Interferometry I 08--6 Herbert Gross Winter term 08 www.iap.uni-jena.de Schedule Optical Metrology and Sensing 08 No Date Subject Detailed Content 6.0. Introduction Introduction,
More informationPIEZOELECTRIC TECHNOLOGY PRIMER
PIEZOELECTRIC TECHNOLOGY PRIMER James R. Phillips Sr. Member of Technical Staff CTS Wireless Components 4800 Alameda Blvd. N.E. Albuquerque, New Mexico 87113 Piezoelectricity The piezoelectric effect is
More informationDesigning a Computer Generated Hologram for Testing an Aspheric Surface
Nasrin Ghanbari OPTI 521 Graduate Report 2 Designing a Computer Generated Hologram for Testing an Aspheric Surface 1. Introduction Aspheric surfaces offer numerous advantages in designing optical systems.
More informationValidation of High Displacement Piezoelectric Actuator Finite Element Models
Validation of High Displacement Piezoelectric Actuator Finite Element Models Barmac Taleghani * Army Research Laboratory Vehicle Technology Directorate NASA Langley Research Center Hampton, VA ABSTRACT
More informationImaging through Kolmogorov model of atmospheric turbulence for shearing interferometer wavefront sensor
Imaging through Kolmogorov model of atmospheric turbulence for shearing interferometer wavefront sensor M.Mohamed Ismail 1 M.Mohamed Sathik 2 1Research Scholar, Department of Computer Science, Sadakathullah
More informationControl of the Keck and CELT Telescopes. Douglas G. MacMartin Control & Dynamical Systems California Institute of Technology
Control of the Keck and CELT Telescopes Douglas G. MacMartin Control & Dynamical Systems California Institute of Technology Telescope Control Problems Light from star Primary mirror active control system
More informationReflecting Telescope Optics II
Reflecting Telescope Optics II Manufacture, Testing, Alignment, Modern Techniques Bearbeitet von Raymond N Wilson überarbeitet 2001. Buch. xviii, 557 S. Hardcover ISBN 978 3 540 60356 6 Format (B x L):
More informationn The visual examination of the image of a point source is one of the most basic and important tests that can be performed.
8.2.11 Star Test n The visual examination of the image of a point source is one of the most basic and important tests that can be performed. Interpretation of the image is to a large degree a matter of
More informationMeasurement of Atmospheric Turbulence with a Shack Hartmann Wavefront Sensor at the new MMT s Prime Focus
Measurement of Atmospheric Turbulence with a Shack Hartmann Wavefront Sensor at the new MMT s Prime Focus Patrick C. McGuire 1, Maud P. Langlois, Michael Lloyd Hart, Troy A. Rhoadarmer, J. Roger P. Angel
More informationIntroduction to Adaptive Optics. Tim Morris
Introduction to Adaptive Optics Tim Morris Contents Definitions and introduction Atmospheric turbulence Components of an AO system Wavefront Sensing Wavefront Correction Turbulence Conjugation Laser Beacons
More informationThermal Corrective Devices for Advanced Gravitational Wave Interferometers
Thermal Corrective Devices for Advanced Gravitational Wave Interferometers Marie Kasprzack, Louisiana State University 6 th October 2016 COMSOL Conference 2016 Boston 1 1. Advanced Gravitational Wave Detectors
More informationCHARA Meeting 2017 Pasadena, California
MORE AUTOMATION Laszlo Sturmann M7 ACTUATORS LAB. LASER ALIGNMENT TELESCOPE OPTICAL ALIGNMENT NEW ACTUATORS REMOTELY ACTUATED M7 MOUNT MOTIVATION THE PRECISION OF THE COUDE ALIGNMENT WAS NOT SUFFICIENT
More informationPiezo Theory: Chapter 1 - Physics & Design
Piezoelectric effect inverse piezoelectric effect The result of external forces to a piezoelectric material is positive and negative electrical charges at the surface of the material. If electrodes are
More informationFinite Element Analysis of Piezoelectric Cantilever
Finite Element Analysis of Piezoelectric Cantilever Nitin N More Department of Mechanical Engineering K.L.E S College of Engineering and Technology, Belgaum, Karnataka, India. Abstract- Energy (or power)
More informationUsing a Membrane DM to Generate Zernike Modes
Using a Membrane DM to Generate Zernike Modes Author: Justin D. Mansell, Ph.D. Active Optical Systems, LLC Revision: 12/23/08 Membrane DMs have been used quite extensively to impose a known phase onto
More informationMetrology and Sensing
Metrology and Sensing Lecture 5: Interferometry I 017-11-16 Herbert Gross Winter term 017 www.iap.uni-jena.de Preliminary Schedule No Date Subject Detailed Content 1 19.10. Introduction Introduction, optical
More informationAdaptive Optics Simulator
FACULDADE DE ENGENHARIA DA UNIVERSIDADE DO PORTO Department of Electrical Engineering and Computers Adaptive Optics Simulator Carlos Correia Da Silva Eduardo Gonçalves da Silva This report aims to present
More informationDevelopment of surface metrology for the Giant Magellan Telescope primary mirror
Development of surface metrology for the Giant Magellan Telescope primary mirror J. H. Burge a,b, W. Davison a, H. M. Martin a, C. Zhao b a Steward Observatory, University of Arizona, Tucson, AZ 85721,
More informationTalk about. Optical Telescopes and Instrumentation. by Christian Clemens
Talk about Optical Telescopes and Instrumentation by Christian Clemens Overview powers of telescopes lens refractors, mirror reflectors interferometry, spectroscopy, optical systems modern observatories
More informationADAPTIVE OPTICS ON GROUND-BASED TELESCOPES
SEMINAR ADAPTIVE OPTICS ON GROUND-BASED TELESCOPES Julija Zavadlav Mentor: doc. dr. Poberaj Igor Ljubljana, January 2010 Abstract: Turbulence in the Earth s atmosphere limits the performance of ground-based
More informationCHAPTER 4 DESIGN AND ANALYSIS OF CANTILEVER BEAM ELECTROSTATIC ACTUATORS
61 CHAPTER 4 DESIGN AND ANALYSIS OF CANTILEVER BEAM ELECTROSTATIC ACTUATORS 4.1 INTRODUCTION The analysis of cantilever beams of small dimensions taking into the effect of fringing fields is studied and
More information440. Simulation and implementation of a piezoelectric sensor for harmonic in-situ strain monitoring
440. Simulation and implementation of a piezoelectric sensor for harmonic in-situ strain monitoring 0. Incandela a, L. Goujon b, C. Barthod c University of Savoie, BP 80439 Annecy-le-Vieux CEDEX, France
More informationChapter 9: Summary and Future Work
Chapter 9: Summary and Future Work 9.1 Summary of Results and Important Contributions The Air Force Research Laboratory Directed Energy Directorate (AFRL/DE) is currently striving to place ultra-large,
More informationMaking FEA Results Useful in Optical Analysis Victor Genberg, Gregory Michels Sigmadyne, Inc. Rochester, NY
Making FEA Results Useful in Optical Analysis Victor Genberg, Gregory Michels Sigmadyne, Inc. Rochester, NY Keith Doyle Optical Research Associates,Westborough, MA ABSTRACT Thermal and structural output
More informationPiezoelectric Actuator for Micro Robot Used in Nanosatellite
Piezoelectric Actuator for Micro Robot Used in Nanosatellite R Bansevicius, S Navickaite, V Jurenas and A Bubulis PIEZOELECTRIC ACTUATOR FOR MICRO ROBOT USED IN NANOSATELLITE. R Bansevicius 1, S Navickaite,
More informationMichelson Interferometer
Michelson Interferometer Objective Determination of the wave length of the light of the helium-neon laser by means of Michelson interferometer subsectionprinciple and Task Light is made to produce interference
More informationPrecise open-loop control of MEMS deformable mirror shape
!nnnvvviiittteeeddd PPPaaapppeeerrr Precise open-loop control of MMS deformable mirror shape Thomas Bifano a,c, Jason Stewart b, Alioune Diouf c a Boston University Photonics Center, 8 Saint Mary s St.,
More informationMeasurements in Optics for Civil Engineers
Measurements in Optics for Civil Engineers I. FOCAL LENGTH OF LENSES The behavior of simplest optical devices can be described by the method of geometrical optics. For convex or converging and concave
More informationMetrology and Sensing
Metrology and Sensing Lecture 5: Interferometry I 06--09 Herbert Gross Winter term 06 www.iap.uni-jena.de Preliminary Schedule No Date Subject Detailed Content 8.0. Introduction Introduction, optical measurements,
More informationOptical/IR Observational Astronomy Telescopes I: Telescope Basics. David Buckley, SAAO
David Buckley, SAAO 17 Feb 2010 1 Some other Telescope Parameters 1. Plate Scale This defines the scale of an image at the telescopes focal surface For a focal plane, with no distortion, this is just related
More informationSDL. Control of the UltraLITE Precision Deployable Test Article Using Adaptive Spatio-Temporal Filtering Based Control
Control of the UltraLITE Precision Deployable Test Article Using Adaptive Spatio-Temporal Filtering Based Control Albert B. Bosse Thomas D. Sharp Stuart J. Shelley Sheet Dynamics, Ltd. Cincinnati, OH Keith
More informationStrain Measurement. Prof. Yu Qiao. Department of Structural Engineering, UCSD. Strain Measurement
Strain Measurement Prof. Yu Qiao Department of Structural Engineering, UCSD Strain Measurement The design of load-carrying components for machines and structures requires information about the distribution
More informationDeformable Mirrors: Design Fundamentals for Force Actuation of Continuous Facesheets
Deformable Mirrors: Design Fundamentals for Force Actuation of Continuous Facesheets S.K. Ravensbergen a, R.F.H.M. Hamelinck b, P.C.J.N. Rosielle a and M. Steinbuch a a Technische Universiteit Eindhoven,
More informationNA LASER GUIDE STAR AO WITH DYNAMICAL REFOCUS
Florence, Italy. Adaptive May 2013 Optics for Extremely Large Telescopes III ISBN: 978-88-908876-0-4 DOI: 10.12839/AO4ELT3.13893 NA LASER GUIDE STAR AO WITH DYNAMICAL REFOCUS Sebastian Rabien 1,a, Fernando
More informationCourse 2: Basic Technologies
Course 2: Basic Technologies Part II: X-ray optics What do you see here? Seite 2 wavefront distortion http://www.hyperiontelescopes.com/performance12.php http://astronomy.jawaid1.com/articles/spherical%20ab
More informationMultilayer Active Shell Mirrors for Space Telescopes
Multilayer Active Shell Mirrors for Space Telescopes John Steeves a, Kathryn Jackson b, Sergio Pellegrino b, David Redding a, J. Kent Wallace a, Samuel Case Bradford a, Troy Barbee c a Jet Propulsion Laboratory,
More informationMichelson Interferometer
Fakultät für Physik und Geowissenschaften Physikalisches Grundpraktikum O10e Michelson Interferometer Tasks 1. Adjust a Michelson interferometer and determine the wavelength of a He-Ne laser. 2. Measure
More informationThe Distributed Defining System for the Primary Mirrors
The Distributed Defining System for the Primary Mirrors Larry Stepp Myung K. Cho Optics Manager Opto-structural Engineer November 5, 1993 GEMINI PROJECT OFFICE 950 N. Cherry Ave. Tucson, Arizona 85719
More informationAUTOMATIC CALIBRATION SYSTEM FOR MICRO-DISPLACEMENT DEVICES. Department of Mechanical Engineering, National Central University 2
59 th ILMENAU SCIENTIFIC COLLOQUIUM Technische Universität Ilmenau, 11 15 September 2017 URN: urn:nbn:de:gbv:ilm1-2017iwk-103:8 AUTOMATIC CALIBRATION SYSTEM FOR MICRO-DISPLACEMENT DEVICES Hung-Ta Shih
More informationElectrostatic Membrane Deformable Mirror Wavefront Control Systems: Design and Analysis
Electrostatic Membrane Deformable Mirror Wavefront Control Systems: Design and Analysis Keith Bush, Dee German, Beverly Klemme, Anthony Marrs, Michael Schoen Intellite, Inc. 1717 Louisiana, NE Suite 202,
More informationMetrology and Sensing
Metrology and Sensing Lecture 5: Interferometry I 07--6 Herbert Gross Winter term 07 www.iap.uni-jena.de Preliminary Schedule No Date Subject Detailed Content 9.0. Introduction Introduction, optical measurements,
More informationx Contents Segmented Mirror Telescopes Metal and Lightweight Mirrors Mirror Polishing
Contents 1 Fundamentals of Optical Telescopes... 1 1.1 A Brief History of Optical Telescopes.................... 1 1.2 General Astronomical Requirements..................... 6 1.2.1 Angular Resolution.............................
More information1 N star coupler as a distributed fiber-optic strain sensor in a white-light interferometer
1 star coupler as a distributed fiber-optic strain sensor in a white-light interferometer Libo Yuan and Limin Zhou A novel technique of using a 1 star fiber optic coupler as a distributed strain sensor
More informationThe AOLI Project Adaptive optics and Lucky Imaging on the William Herschel Telescope
The AOLI Project Adaptive optics and Lucky Imaging on the William Herschel Telescope David King Institute of Astronomy University of Cambridge 30 January 2013 1 Introduction The AOLI - what is AOLI and
More informationThe Principles of Astronomical Telescope Design
The Principles of Astronomical Telescope Design Jingquan Cheng National Radio Astronomy Observatory Charlottesville, Virginia,.USA " 4y Springer Fundamentals of Optical Telescopes 1 1.1 A Brief History
More informationOptics.
Optics www.optics.rochester.edu/classes/opt100/opt100page.html Course outline Light is a Ray (Geometrical Optics) 1. Nature of light 2. Production and measurement of light 3. Geometrical optics 4. Matrix
More informationDesign and Simulation of A MEMS Based Horseshoe Shaped Low Current Lorentz Deformable Mirror (LCL-DM).
Design and Simulation of A MEMS Based Horseshoe Shaped Low Current Lorentz Deformable Mirror (LCL-DM). Byoungyoul Park 1, Tao Chen 1, Cyrus Shafai 1 1 Electrical and Computer Engineering, University of
More informationSensors and Transducers. mywbut.com
Sensors and Transducers 1 Objectives At the end of this chapter, the students should be able to: describe the principle of operation of various sensors and transducers; namely.. Resistive Position Transducers.
More informationFabrication of EUVL Micro-field Exposure Tools with 0.5 NA
Fabrication of EUVL Micro-field Exposure Tools with 0.5 NA EUV Litho, June 15 th, 2016 Luc Girard 1, Lou Marchetti 1, Jim Kennon 2, Bob Kestner 2, Regina Soufli 3, Eric Gullickson 4 1 Zygo Corporation,
More informationThin-disk laser Power scaling to the kw regime in fundamental mode operation
Thin-disk laser Power scaling to the kw regime in fundamental mode operation J. Mende*, E. Schmid, J. Speiser, G. Spindler and A. Giesen German Aerospace Center, Institute of Technical Physics, Pfaffenwaldring
More informationGravitational Waves & Precision Measurements
Gravitational Waves & Precision Measurements Mike Smith 1 -20 2 HOW SMALL IS THAT? Einstein 1 meter 1/1,000,000 3 1,000,000 smaller Wavelength of light 10-6 meters 1/10,000 4 10,000 smaller Atom 10-10
More informationMounts for large lens in cooled environment
Mounts for large lens in cooled environment Thierry VIARD / Christophe DEVILLIERS Thales Alenia Space TAS Cannes La Bocca, France Thierry.viard@thalesaleniaspace.com Vincent COSTES / Didier GANGLOFF Centre
More informationOptical/IR Observational Astronomy Telescopes I: Telescope Basics. David Buckley, SAAO
David Buckley, SAAO 27 Feb 2012 1 Some other Telescope Parameters 1. Plate Scale This defines the scale of an image at the telescopes focal surface For a focal plane, with no distortion, this is just related
More informationThe aims of this experiment were to obtain values for Young s modulus and Poisson s ratio for
The Cornu Method Nikki Truss 09369481 Abstract: The aims of this experiment were to obtain values for Young s modulus and Poisson s ratio for Perspex using the Cornu Method. A value of was found for Young
More informationIntegrating MD Nastran with Optical Performance Analysis
Integrating MD Nastran with Optical Performance Analysis Victor Genberg, Gregory Michels Sigmadyne, Inc., 803 West Ave, Rochester, NY 14611 genberg@sigmadyne.com Abstract The development of products in
More informationLecture 19. Measurement of Solid-Mechanical Quantities (Chapter 8) Measuring Strain Measuring Displacement Measuring Linear Velocity
MECH 373 Instrumentation and Measurements Lecture 19 Measurement of Solid-Mechanical Quantities (Chapter 8) Measuring Strain Measuring Displacement Measuring Linear Velocity Measuring Accepleration and
More information