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Adaptive Optics for the Thirty Meter Telescope

Adaptive Optics for the Thirty Meter Telescope. Brent Ellerbroek Thirty Meter Telescope Observatory Corporation AO4ELT3 Florence, Italy May 27, 2013. Contributors.

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Adaptive Optics for the Thirty Meter Telescope

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  1. Adaptive Optics for the Thirty Meter Telescope Brent Ellerbroek Thirty Meter Telescope Observatory Corporation AO4ELT3 Florence, Italy May 27, 2013 TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  2. Contributors Brent Ellerbroeka, Sean Adkinsb, David Andersenc, Jenny Atwoodc, Arnaud Bastardd, Yong Boe, Marc-André Boucherc, Corinne Boyera, Dmitri Budkerf, Peter W. G. Byrnesc, Kris Caputac, Jeffrey Cavacog, ShanqiuChenh, Carlos Correiac, Raphael Coustyd, Joeleff Fitzsimmonsc ,Luc Gillesa, James Gregoryi, Glen Herriotc, Paul Hicksonj, Alexis Hillc, ZuoJunweie, Zoran Ljusicc, N. Marchetd, Angel Otarolaa, Dan O’Marai, Leo Myerk, Benoit Neichell, John Pazderc, Hubert Pagesd, Spano Paoloc, Robert Priorc, Vladimir Reshetovc, Simon Rochesterf, Jean-Christophe Sinquing, Matthias Schoeckc, Malcolm Smithc, Kei Szetoc, JinlongTangh, Jean-Pierre Veranc, Lianqi Wanga, Kai Weih, Ivan Weversc, and Sylvana Yeldak aTMTObservatory Corporation, bW. M. Keck Observatory, cNRC Herzberg, dCILAS, eTechnical Institute of Physics and Chemistry, fRochesterScientific, gAOAXinetics, hInstituteof Optics and Electronics, iMITLincoln Laboratory, jUniversityof British Columbia, kUniversity of California at Los Angeles, lGemini Observatory TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  3. Presentation Outline • TMT Project highlights • First light AO requirements review • Derived architecture and technology choices • Subsystem status report • NFIRAOS; LGSF • Component development • Deformable mirrors; wavefront sensing detectors; guidestar lasers; real time controller • Modeling and algorithm development • Related papers at AO4ELT3 • Acknowledgements TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  4. TMT Project Highlights • Site permit approved by the Hawaiian BLNR • Geotechnical studies and ground preparation to begin this year • Construction start date slated for April 2014 • Construction Phase funding proposals under review in Canada, India, and Japan, and China • Yale University has committed to joining the Project • NSF Cooperative Agreement signed • Instrument design work progressing well • IRIS Preliminary Design Phase initiated May 2013 • IRMS delta Design Review (from MOSFIRE) held April 2013 • MOBIE Conceptual Design Review in September 2013 • First light scheduled for 2022 TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  5. First Light AO Requirements Review • 3 science ports at f/15 with 2 arc min unvignetted field • High throughput (85% in J, H, K, and I bands) • Low thermal emission (15% of sky + telescope) • Diffraction-limitedIR image quality on a moderate FoV • [187, 191, 208] nm wavefront error over a [0,17,30] arc sec field • High sky coverage (50% at galactic pole) • High photometric accuracy • 2% over 30 arc sec at l=1 mm for a 10 minute observation • High astrometric accuracy • 50 mas over 30 arc sec in H band for a 100 second observation • High observing efficiency TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  6. How First Light Performance Requirements Drive AO Architecture Decisions High-order LGS MCAO with NGS tip/tilt/focus sensing in the Near IR TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  7. First Light AO System Architecture and Technology Choices Laser Launch Telescope • Laser Guide Star Facility (LGSF) • Nd:YAG or Raman fiber laser tech-nology • Lasers mounted on telescope elevation journal • Conventional beam transport (mirrors) • Center-launch laser projection Beam Transfer Optics Laser Systems TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  8. First Light AO System Architecture and Technology Choices • Narrow Field IR AO System (NFIRAOS) • Piezostack deformable mirrors and tip/tilt stage • “Polar coordinate” CCD array for the LGS WFS • HgCdTe CMOS arrays for low order, infra-red NGS WFSs (in client instruments) NFIRAOS facility AO TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  9. Project Participants UBC, Vancouver (Sodium LIDAR) TIPC, Beijing (Laser Systems) HIA, Victoria (NFIRAOS) TOPTICA, Munich (Laser Systems) DRAO, Penticton (RTC) MIT/LL, Lexington (WFS CCDs) AOA/Xinetics, Devens (Wavefront Correctors) CILAS, Orleans (Wavefront Correctors) IOE, Chengdu (Laser Guide Star Facility) Keck Observatory, Waimea (WFS readout electronics) TMT, Pasadena (Management and SE) Also Rochester Scientific (Berkeley, Sodium Atomic Physics) TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  10. NFIRAOS Status Update Opto-mechanical layout • “Pre-Final” Design Phase is now underway • Prototyping/test activities include: • DM drive electronics development • DM breadboard testing • WFS lenslet testing • Instrument rotator interface • Component testing at -30C • MCAO lab bench development • Design work will include: • NGS WFS optics bench • LGS WFS zoom optics • NFIRAOS instrument support tower • FEA for vibration/thermal/seismic effects NFIRAOS on Nasmyth TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  11. NFIRAOS Prototypes and Testbeds 96-channel DM drive electronics board MCAO test bench Phase Screen Location DM’s LGS WFS Path “Science” Path Source simulators TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  12. Recent LGSF Design Activities • Design updated for new MELCO telescope structure: • (Yet another) optical path trade study • 2-axis launch telescope flexure compensation system • Laser system and laser bench layout on telescope elevation journal • Details of beam tube diameter, relay lens design, and top end layout • Beam tube turbulence modeling underway • LGSF Preliminary Design phase scheduled to begin November 2013 TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  13. LGSF Optical Path Trade Study Baseline OP New OP TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  14. Work in Progress on Beam Duct Turbulence Modeling CAD model of Fold mirror array and relay lenses Difference from mean interior air temperature TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  15. AO Component Requirement Summary TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  16. DM Development • Initial testing of the CILAS 6x60 actuator breadboard has been completed in early 2013 • Good actuator-level performance at ambient and low temperature (-30C) • Not all requirements met at the full breadboard level • New round of development underway • New study initiated at AOA Xinetics • Evaluate actuator performance at -30C • Develop DM conceptual designs meeting TMT performance and interface requirements TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  17. One-Quadrant Prototype LGS WFS CCDs • Front- and back-illuminated devices now tested • Meet specs for QE and CTE • Read noise of 2.7 to 3.7 e- at 3.5 MHz (3 e- requirement) • Dark current sufficiently low for 800 Hz frame rate • BI devices have good yield • 3 of 8 probed CCDs show very good performance • 99% of outputs functional, 99% low noise Black: QE spec and allowed nonuniformity Red: Measuremented QE (Courtesy Keck Observatory) TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  18. NGS WFS CCDs for NFIRAOS Engineering Grade Device in Test Station • MIT/LL CCID-74 • 256x256 pixels • 64 planar JFET amplifiers • Testing of back-illuminated engineering devices now in progress at Keck • High QE as above (for Polar CCD) • Dark current of 26 electrons/pixel/second • Read noise approaches 1 electron at 100 FPS • Candidate science grade CCDs will be packaged for testing and potential use as the deliverable NGS WFS CCD for NFIRAOS Measured read noise at -15C with 32 Amplifiers TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  19. Guidestar Laser Systems • TMT continues to follow two laser development efforts: • Toptica/MPB frequency-doubled Raman fiber laser meets all TMT requirements for output power, line width, beam quality, volume, and power dissipation • some TMT interfaces will require development • Work on TIPC prototype SFG Nd:YAG laser is continuing: • Currently 18W@800Hz power for 100μs pulse • M2 ~ 1.5 • Line width of 0.6 GHz, with 0.2 GHz wavelength stability • On-sky tests in early 2013 confirm high sodium coupling efficiency for a large spot size without repumping • Further on-sky tests (with repumping) planned later this year TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  20. TIPC Nd:YAG SFG Guidestar Laser System Laser System and Optical Schematic Lijiang Observatory, February 2013 TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  21. Laser Coupling Efficiency (Sce) vs. IrradianceResults from Lijiang, China, February-March 2013 • Results were obtained for: • Various Power Levels • 800 Hz or 600 Hz Pulse Repetition Rate • Pulse lengths 95 to 100 micro-secs • Results, as expected, show the effect of optical saturation • TMT Specification: 120 Photos/W/s/(atoms/m2) • Sce at higher Irradiance levels can be improved with D2b repumping and may reach the TMT Specification • More tests with repumping and smaller spot sizes planned TMT.AOS.PRE.12.073.DRF01

  22. Real Time Controller (RTC) Architectures • RTC architecture study now underway at NRC Herzberg and TMT to update RTC conceptual designs from 2008-09 • Benchmarking and design of a GPU-based architecture is currently most advanced • 2 GPUs per WFSimplement gradient computation and matrix-vector-multiply (MVM) wavefrontreconstruction • Matrix updated at 0.1 Hz Benchmark results: 0.95ms mean latency, 1.05 ms peak Timing includes gradient computation, MVM computation, data transfer over 10 Gig ethernet TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  23. Recent Work in AO Modeling and Control Algorithm Development • AO Error budget maintenance and sky coverage analysis • Incorporates improved modes for optical surface errors and sodium range tracking • Performance trade studies for OIWFS passband and detector choices • High precision astrometry • High contrast imaging • PSF reconstruction lab tests with GeMS • Analysis of LGS Fratricide amplitude for GeMS • On-instrument WFS guidestar acquisition • Distributed (computationally efficient) Kalman Filter tomography • LGS SLODAR for Cn2_and wind velocity_ profile estimation • MCAO Lab Bench development at NRC-Herzberg also continuing TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  24. AO Performance Estimate(Zenith,median seeing, 50% sky coverage) TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  25. AO Sky Coverage vs. OIWFS Detector Option and Spectral Passband • Median seeing • Galactic pole guidestar densities • Zenith angles from 0 to 50 degrees • Widening the spectral passband from JH to JHKs improves sky coverage by ~10% • Switching from the H2RG detector to SELEX APDs would yield another ~5% improvement 191 TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  26. Median AO Performance vs. Galactic Latitude and Longitude (at Transit) Median seeing TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  27. Median AO Performance vs. Galactic Latitude and Longitude (at Transit) Good (25%) seeing TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  28. High Precision Astrometry for Observations of the Galactic Center • Many sources of error have been investigated: • Photon, detector, thermal noise • Differential tip/tilt jitter • Distortions: • Probe arm positioning error • Geometric (static) • PSF estimation • Confusion • Single-epoch error budget: • Bright stars (K < 15): distortion dominates (~8 μas) • Faint stars (K > 15): confusion dominates (> 8 μas) TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  29. High Contrast Imaging • IRIS imager optics now included in modeling • NFIRAOS+IRIS equivalent to ~1h of Gemini/Keck in 30 s • Approaches GPI performance in 1-2 h, assuming 50x of SSDI speckle suppression (hard) • Better astrometry and higher SNR for high res. spectroscopy • Fainter and more distant targets? TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  30. Progress in PSF Reconstruction GEMs (Canopus) references sources and ground-conjugate DM used to generate long-exposure PSFs and simultaneous WFS telemetry PSFs with Strehls of ~40% estimated to within 1-2% relative error Next step: Wide-field PSF reconstruction for MCAO using both DMs TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

  31. Related Papers at AO4ELT3

  32. Acknowledgements • The TMT Project gratefully acknowledges the support of the TMT partner institutions. • They are • the Association of Canadian Universities for Research in Astronomy (ACURA), • the California Institute of Technology • the University of California • the National Astronomical Observatory of Japan • the National Astronomical Observatories and their consortium partners • And the Department of Science and Technology of India and their supported institutes. • This work was supported as well by • the Gordon and Betty Moore Foundation • the Canada Foundation for Innovation • the Ontario Ministry of Research and Innovation • the National Research Council of Canada • the Natural Sciences and Engineering Research Council of Canada • the British Columbia Knowledge Development Fund • the Association of Universities for Research in Astronomy (AURA) • and the U.S. National Science Foundation. TMT.AOS.PRE.13.081.DRF01 AO4ELT3, Florence, Italy, 05/27/2013

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