ELT Technology Development at the Anglo-Australian Observatory

1. ELT Technology Development at the Anglo-Australian Observatory Samuel C. BardenHead of Instrumentation

2. AAO Instrumentation Group • Builds facility class instrumentation for the AAO and other international observatories • Staff of ~20 • 2 project managers • 5 mechanical engineers • 2 mechanical designers • 3 electrical engineers • 2 electronic technicians • 6 software programmers

3. AAO Instrumentation Group • Works closely and under guidance of the AAO Instrument Science Group • Staff of 4 under leadership of Joss Bland-Hawthorn • Roger Haynes • Andrew McGrath • Will Saunders • (Anthony Horton)

4. AAO Instrumentation Group • Areas of instrumentation development include: • Tunable filters • Fiber optics • Positioners and robotics • VPH gratings • Optical and NIR imagers and spectrographs • ELT telescope concepts • These technologies are relevant for ELTs

5. AAO Instrumentation Effort • Ongoing Projects (Instrument Program Effort) • AAOmega • FMOS/Echidna • WFMOS (Feasibility Study for Gemini) • ELT Technologies (Instrument Science Research) • Starbugs • Photonic Fibers • OH Suppression Fibers • Other ELT Ideas (Low level Instrument Science Research) • Telescope Concepts • Inertial Drives • Direct ELT Involvement • Instrument Concept Study with GMT

6. Bench spectrograph for 2dF Dual Beam ~400 fibers (36 meter length) 370-950 nm R=1000 to ~10000 VPH gratings Articulated cameras 2x4k detectors Current Projects AAOmega Commissioning to take place at end of this year

7. Current Projects FMOS/Echidna • 400 fiber positioner for Subaru • Piezo tip-tilt spine technology

8. WFMOS aka KAOS Field of View: ~1.5 degree diameter Simultaneous Targets: 3000 low resolution 1500 high resolution Wavelength Range: 0.39 – 1.0 mm (optical) Spatial Sampling: ~1 arc-second apertures Spectral Resolving Power (l/Dl): ~1000 to 40000 Implementation on Subaru telescope Current Projects WFMOS is an ELT sized project

9. Current Projects WFMOS Concept – Corrector

10. AAO Instrumentation Effort • ELT Technologies (Instrument Science Research) • Starbugs • Photonic Fibers • OH Suppression Fibers

11. ELT Technologies Starbugs/Kickbots • Actuators for image relays and fibers • For ELT instrument development • Current study funded by FP6 Opticon (Smart Focal Planes)

12. ELT Technologies Starbugs/Kickbots See talk by Roger HaynesFriday afternoon

13. ELT Technologies Astrophotonics • Mission: • Investigate use of new photonic technologies for current and next generation astronomical instrumentation. • Funding • PPARC innovative technology grant in partnership with University of Durham • Applications • Spectroscopy: High resolution and wide field multi-object systems. • Imaging: Integral field systems (imaging spectroscopy), acquisition and guiding • Interferometry: Coherent beam transport (IR) • High Power Laser Transport: Rayleigh and Sodium guide stars feeds • Filtering: Noise suppression • Data Transfer: High speed optical data links

14. ELT Technologies OH Suppression Optical sensitivity (point source) from ground can reach mAB ~ 28 (5) Near IR sensitivity does not even come close! This is not a detector problem 99% of background in OH lines

15. ELT Technologies Introduction to fibre Bragg gratings • What is an FBG? • A single mode fibre with a periodically varying refractive index • FBGs reflect a narrow band of wavelengths depending on period  of varying refractive index, B = 2 no  • Periodic refractive index is printed on fibre core by UV interference • Refractive index increases in proportion to UV flux Refractive index, core Position along fibre

16. ELT Technologies OH grating design  = normalized frequency Solve for amplitude, phase Ef,Eb are forward/backward propagating modes κ = coupling efficiency Bland-Hawthorn, Englund & Edvell (2004)

17. Prototype 1 (Single Mode Fibre – 36 OH lines – R=10k) R=10,000 seems ideal though R=55000 is possible R=30,000 OH doublets resolve R=150,000 OH lines resolve Measured fibre loss is 4% Application: Ideally matched to diffraction limited performance The future: We now believe we can knock out all lines in JHK with a single FBG design Bland-Hawthorn, Englund & Edvell 2004

18. ELT Technologies Excellent manufacturing repeatability

19. Prototype 2 (158 lines suppressed, R=10k) Just made… Prototype 1 suppression for comparison Bland-Hawthorn, Englund & Edvell 2005

20. Prototype 3 (Multi-Mode Fibre): First ever demonstration of FBG in multimode fibre.35 micron core – 19 SMF – R=10k notch Measured response from FBG inserted directly into MMF… Continuum structure has nothing to do with grating… Measured vs Predicted If notch had been imprinted in MMF fibre. Factor of 200x spread in width! Bland-Hawthorn, Birks, Leon-Saval, Englund (2005) (First Prize for New Technology at Optical Fiber Conference in April 2005)

21. Three grating fibres under development Hope to have a MMF device available for on-sky tests during coming year.

22. AAO Instrumentation Effort • Other ELT Ideas (Low level Instrument Science Research effort) • Telescope Concepts • Inertial Drives

23. HTMT: 15x30mwith 1 deg field

24. WHAT: 8m Schmidt with 3 deg field

25. permanent magnet field assembly (moves with shaft) small air bearing large air bearing moving shaft with mass ~ 8 kg coil (stationary) Inertial Drives • For control of wind buffeting

26. Concluding Comments We are striving to uncover technologies that will further enhance ELT capabilities (as well as the smaller aperture telescopes). We hope to develop prototype starbug and OH suppression instruments in the near future. And, we look forward to further involvement in the development of ELT instruments.