Adaptive Optics for ELTs
Strategic Investment for the Future
Stephen Strom, NOAO
Claire Max, CfAO
Jerry Nelson, CfAO
Matt Mountain, Gemini
Adaptive Optics Road Map
Presentation Outline
• Why we are here
• Key messages
• Current status of AO
• Recent AO results; new frontiers in AO
• AO is essential for ELTs
• The scientific promise of AO systems on ELTs
• Current investments and world competition
• The need for coordinated investment using a roadmap
– A proof of concept: laser development
• A national roadmap for AO technology development
• Approximate schedule and funding
• Recommendations for Implementing a Roadmap
Adaptive Optics Road Map
Why we are here
• Provide updates on recent AO developments
• Seek endorsement of CAA for:
– NSF strategic investments in AO for ELTs using a
community-developed “AO roadmap” as a guide
– A recommended process for planning and coordinating
investments in adaptive optics
• Context:
– Builds on a key decadal survey recommendation: implement a
major AO program to enable ELTs
– Provides key components; systems in time for ELTs
Adaptive Optics Road Map
Key Messages
• AO is now delivering quantitative science results
• Capable and robust AO systems are critical to enabling and
fully exploiting investments in ELTs
• Critical ELT systems and components are well beyond the
state-of-the-art
• Large and sustained investment is needed to ensure AO
readiness for ELTs by early in the next decade
• Investments must be guided by a strategic plan
– AO community has developed a consensus roadmap
• NSF funding for AO could serve as early federal investment
in a public-private GSMT
– aligned with AASC recommendation re GSMT
Adaptive Optics Road Map
AO Workshop:
Participants + Consensus
Name
Affiliation
Roger Angel
Todd Boroson
Jim Breckinridge
Rich Dekany
Mark Ealey
Brent Ellerbroek
Bob Fugate
Ed Kibblewhite
Claire Max
Jerry Nelson
Scot Olivier
Andreas Quirrenbach
Thomas Rimmele
Mike Shao
Steve Strom
Laird Thompson
Allan Wirth
Peter Wizinowich
University of Arizona
National Optical Astronomy Observatory
National Science Foundation
Jet Propulsion Laboratory
Xinetics Corporation
Gemini Observatory
United States Air Force
University of Chicago
Lawrence Livermore National Laboratory
University of California, Santa Cruz
Lawrence Livermore National Laboratory
University of California, San Diego
National Solar Observatory
Jet Propulsion Laboratory
National Optical Astronomy Observatory
University of Illinois
Adaptive Optics Associates, Inc.
W. H. Keck Observatory
Support Coordinated Strategic Investments:
Implement a Roadmap Process
Adaptive Optics Road Map
Key Messages
• Investing in AO and following a roadmap will:
– Create much needed sustained investment in key AO
components and systems
– Enable ELTs to operate successfully
– Achieve full benefits of ELT investments
– Enhance performance of existing telescopes
Adaptive Optics Road Map
AO: Current Status
• AO systems to date demonstrate its potential to:
– deliver high fidelity, diffraction-limited images
– enable large gains in sensitivity
– improve photometric accuracy in crowded fields
– reduce the size of instruments
• Science enabled by AO is impressive
– Measuring proper motions in the Galactic Center
– Imaging accretion disks; precessing jets in YSOs
– Resolving dense galactic and globular clusters
– Measuring stellar fluxes; colors in nearby galaxies
– Imaging planets and their satellites at high resolution
Adaptive Optics Road Map
AO: Current Status
However………
• Only a small percentage of the sky is accessible to current
AO systems: laser guide stars needed
• Laser systems are still very expensive, based on immature
technology, and not robust
• Detectors and DMs still limit performance
• Wavefront sensing approaches not yet optimized
• Data reduction techniques still under development
• AO correction still limited to small FOVs
But there has been substantial progress
Adaptive Optics Road Map
Recent Results:
Quantitative Photometry
• AO performance can be well modeled
– Predictions of image quality from models of
atmospheric turbulence + optics confirmed
• AO PSF fitting tools work well
• Photometric errors in crowded fields ~2%
– NICMOS vs AO photometry compares well
Adaptive Optics Road Map
Recent Results:
Quantitative Photometry
Galactic Center Region –
40”x40” composite
AO corrected H & K
Adaptive Optics Road Map
Recent Results:
Quantitative Photometry
Adaptive Optics Road Map
Recent Results:
Black Hole at the Center of the Milky
Way:Narrow-Field AO
1”
No AO
AO-on
Adaptive Optics Road Map
Recent Results:
The Black Hole at the Center of the
Milky Way: Narrow Field AO
Multiple observations
enable
motion
Velocityproper
dispersion
measurements.
vs radius yields
black-hole mass
Symbol size ~ m
Adaptive Optics Road Map
Recent Results:
Dual Black Holes at the Core of NGC 6240
WFPC2
2 merging disk galaxies
Adaptive Optics Road Map
Recent Results:
Dual Black Holes at the Core of NGC 6240
Chandra
high energy xrays
Keck AO
K band
NICMOS
J-H-K
Adaptive Optics Road Map
The Next Frontier: Wide Field Imaging with
Adaptive Optics Using MCAO
Ragazzoni et al, 2000:
• Collected optical data on a
•
•
constellation of 4 stars
Used outer 3 stars to
predict phase errors for
the central star
Atmospheric phase error
estimates superior to
classical AO
– MCAO will work!
Adaptive Optics Road Map
Multiconjugate AO
Multiple laser guide stars
One laser
guide star
Unsampled
turbulence
Primary mirrors
Deformable mirrors
conjugate to each
turbulent layer, for
larger field of view
Adaptive Optics Road Map
MCAO Can Provide Major Gains in FOV
•
Predicted performance of MCAO vs CAO:
– Field of view area gain: J: 20-80 x, K: 10-20 x,
depending on conditions
MCAO
– Photometric performance: accuracy proportional to
Strehl variations over the1/2
fieldFoV
– MCAO should deliver 0.5% accuracy over 1-2’ FOV, or
1/2 FoV
more than 10x CAO
AO
Enabling MCAO 0will 10
require
investments
20”
40”
40”
20 major
30 40
50 60
a
[arcsec]
Adaptive Optics Road Map
AO is Essential for ELTs
• AO (at least low order) may be required to compensate for the
effects of wind-buffeting
• Capable AO systems are essential for reaping full value from
investments in ELTs
– Gains in point source sensitivity ~ D4 for diffraction-limited
resolution in background-dominated images
– Cost of an ELT ~ D2
– Benefit/cost ratio ~ D2 if AO can deliver high Strehl images,
ultimately over substantial fields of view (MCAO)
• Instrument size is prohibitively large absent AO
• Science benefits are dramatic. For example:
– Finding and characterizing planets
– Characterizing component stellar pops in galaxies
– Determining properties of forming galaxies
Adaptive Optics Road Map
ELT AO Science: Stellar Populations
20”
M 32 (Gemini/Hokupaa)
NGST
GSMT with MCAO
Adaptive Optics Road Map
ELT AO Science : Galaxy Evolution
Courtesy of M. Bolte
Adaptive Optics Road Map
Current Investments in AO for ELTs
•
•
•
CfAO + NIO + Gemini (US share) + CELT + CAAO + UCSC-LAO:
~ $6M/yr
Key activities for existing groups:
– CfAO: design studies; simulations; modest Na laser development
– NIO: site characteristics; system studies; simulations
– Gemini: MCAO science demonstrator, algorithms, Na Laser
development
– CELT: site characteristics; system studies; simulations
– CAAO: deformable secondaries; Rayleigh laser beacons
– LAO: testing of subscale prototypes & AO components
Bottom line:
– These investments (private; state; federal; international) provide
support for first steps toward ELT-capable AO
– Key component developments need significant support
Adaptive Optics Road Map
Current Investments: Europe
• ESO –VLT will field first MCAO demonstrator
late 2003 (already through CDR)
• In 2004 VLT MCAO program will explore alternative
approaches, e.g.
– layer-oriented vs. tomographic techniques
• European network (OPTICON) established to coordinate and
enhance European institutions AO modeling and simulation
capabilities
– funding post-docs at between 10-15 FTE’s/year
• ESO now funding at least two parallel Na laser technology
studies (e.g. fiber lasers)
• 100m OWL is a highly effective coordinating force behind
European AO efforts
Our European colleagues are moving ahead aggressively
Adaptive Optics Road Map
The need for NSF-supported Strategic
Investment in AO for ELTs
•
Providing AO systems for ELTs will require a sustained, coordinated
effort
• Low order adaptive secondaries
• High performance, narrow-field AO
• High Strehl, wide-field AO (via MCAO)
•
Funding & timescales must be matched to the challenges
•
A successful example of a coordinated, strategic approach is already
in hand: development of Na laser guide stars
Adaptive Optics Road Map
The Potential of Na Laser Guide Stars
AO off
ALFA AO System (Calar
Alto): Na laser produced
images with S ~ 0.2, within a
factor of 2 of prediction
And now Lick is producing S
~ 0.7, with the potential of
(nearly) all-sky imaging
LGS AO
Adaptive Optics Road Map
Today’s Na lasers are not yet robust
Keck
dye
laser
Lincoln
Labs
Solid
State Laser
Adaptive Optics Road Map
New laser approaches are promising but
not yet mature
•
Solid-state sum-frequency lasers
– Air Force system
– Gemini laser project
•
Fiber lasers
– ESO Raman laser
– LLNL-ESO-CfAO sum-frequency laser
Adaptive Optics Road Map
Meeting the Challenge: Defining a long-term
laser development program
• The AO roadmap effort highlighted the lack of a robust Na laser
technology as critical to further AO development
• However, the non-recurring costs of developing viable, lasers for Gemini, Keck
and others was beyond the resources of any of the major adaptive optics
programs
• A focused, community-wide effort (Gemini, CfAO, Keck, USAF)
was needed to develop “turn-key” affordable Na lasers for all
ground-based telescopes
Adaptive Optics Road Map
First Test of a Roadmap Approach
•
Gemini+CfAO+Keck+USAF (SOR) identified common system and
component requirements
•
AURA, NSF and USAF worked together to identify funding to support a
laser commercialization effort
– used LIGO approach as a model
– goal is to enable a committed private sector company to develop a
product line
•
Results to date:
– $5.2M already raised (further $4.3M requested from NSF)
– Contract almost in place for first “commercial” 10W Na Laser
• first step toward a fully-engineered, robust laser
• additional funding may be needed to develop a product line
– First successful tests at SOR of “diode” 10W prototype for
engineering 50W demonstrator
Adaptive Optics Road Map
What New Investments are Needed?
• ELT studies identify as critical needs:
– Deformable mirrors: thousands of actuators, large stroke; sizes ranging
from 20-200 cm
– Lasers (started but not completed): ~ 20-50W Na lasers (fully engineered to
be robust and reliable)
Sustained investment over 5-10 years is critical
• 5-10 needed for ELTs; other systems
– CCDs: large format, fast readout, low noise for wavefront sensing
(512x512; ~kHz readout rates; 2e- read noise)
– IR detectors: fast readout, low-noise for tip-tilt & focus sensors
• The requirements for each component well exceed the current
state-of-the art
• Costs to develop needed components far exceed current investment
levels
Adaptive Optics Road Map
Implementing an AO Roadmap
• Build on June 2000 AO Roadmap report
– consensus of CfAO + AURA-NIO workshop
• broadly-based, fully representative group
– collaborative Na Laser program the first experiment
• Take into account the rapidly accelerating international efforts to
develop AO systems
– Most cited AO science papers come from CFHT and ESO not
from US telescopes (Crabtree 2002)
– SPIE 2002 meeting provided clear evidence of impressive
investment by the international community
– Our colleagues in Europe are now developing highly capable
systems for use with the VLT
• Both MCAO and “Extreme AO” systems
Adaptive Optics Road Map
Part II
•
Outline of national roadmap for ELT AO
technology development
• Key technologies, impacts
• Schedule with milestones
•
•
•
Approximate funding level required
Recommendations for proposed roadmap process
Desired outcomes of this discussion
Adaptive Optics Road Map
Key Technologies: Laser guide stars
• Proposed Investment:
– Na: develop fully-engineered, robust and affordable lasers
– Rayleigh beacons: study and support integration into one or more
demonstration systems relevant to ELTs
• Expected Return:
– Wider-field correction through use of MCAO on ELTs
– Availability for multiple applications on existing telescopes
(full sky coverage)
– Extending AO corrections to shorter wavelengths (e.g. visible
light on existing telescopes)
Adaptive Optics Road Map
Schedule of Key Activities: Lasers
03
04
05
06
07
08
09
10
Na laser development
• Fund NSF’s share of
current collaboration with
Air Force, Gemini
• Fully engineered ~50
W solid-state lasers (already
underway)
• Advanced concepts (e.g.
fiber lasers)
Rayleigh laser development
• Study ELT concepts
• Integrate into ELT plans if initial
results are favorable (Arizona;
Durham)
Commercialization
• Fund commercialization of
several promising approaches
(LIGO laser as a model)
• Goal: to create competition of
at least two committed private
sector companies to develop
product lines
Adaptive Optics Road Map
Key Technologies: Deformable Mirrors
• Proposed Investment:
– Prototype and test wavefront correction elements
with thousands of degrees of freedom; high stroke
• MEMs
• Adaptive secondaries
• Thin face sheet DMs: extrapolate current
technology to more actuators; lower cost
• Expected Return:
– Enable ELTs that deliver full AO potential
– Lower cost/degree of freedom for existing telescopes
– Provide higher Strehl at shorter wavelengths
Adaptive Optics Road Map
Schedule of Key Activities: Deformable
mirrors
03
04
05
06
07
08
09
10
Requirements
Subscale prototypes
• Construct, compare on modest scale
Full scale prototypes
•
Construct and test ELT-scale prototypes of most
promising technologies
Adaptive Optics Road Map
Two deformable mirrors with 1000 actuators
Xinetics, ~12” clear aperture
MEMS
~ 1 cm
Key Technologies: Wavefront Sensing-1
• Proposed Investment:
– Faster, lower noise detectors
• Visible light: CCDs for wavefront sensing (need more
pixels)
• IR: arrays for tip-tilt, focus, ... sensing
• Expected Return:
– Enables wavefront sensing for ELTs
– Provides greater sky coverage for existing telescopes
• Enable use of fainter natural guide stars, less powerful
lasers
Adaptive Optics Road Map
Key Technologies: Wavefront Sensing-2
• Proposed Investment:
– Develop alternative wavefront sensing techniques
(today all AO systems use either Shack-Hartmann
or curvature)
• Direct phase measurements
• Pyramid sensing
– Compare performance, optimize for different
astronomical AO goals
• Expected Return:
– Use available photons more efficiently for specific
applications
Adaptive Optics Road Map
Schedule of Key Activities: Detectors
03
04
05
06
07
08
09
10
Requirements
Foundary runs
• Evaluate performance
• Coordinate with DoD
Select most
promising
technology
Full scale prototypes
Production runs for 5122 detectors (visible) and
very low-noise IR arrays
Adaptive Optics Road Map
•
Schedule of Key Activities: Wavefront sensing
concepts
03
04
05
06
07
08
09
10
Analysis and simulation
Test concepts in lab
• Compare for differing applications
• What are fundamental performance
limits of Shack-Hartmann, pyramid
sensing, direct phase measurement
Optimize for specific applications
Adaptive Optics Road Map
Key Technologies: End-to-end Comparison of
Competing Systems Concepts
•
Proposed Investment:
– Evaluate and compare competing systems approaches
• e.g., end-to-end comparison of layer-oriented vs tomographic approaches
for 30m telescopes
• benefits of multi-conjugate AO vs ground-layer compensation for selected
science programs
•
Expected Return:
– Choice of optimum architecture for ELTs
– Improved performance on existing telescopes
Realizing the full capabilities of a diffraction limited 30 m
telescope is a technological challenge. But it is
achievable with sustained investment.
Adaptive Optics Road Map
Schedule of Key Activities: ELT AO concepts
03
04
05
06
07
08
09
10
Analysis and simulation
• End-to-end simulations of
competing approaches
• Tomographic vs. layer-oriented
• Ground-layer AO vs. MCAO
Test and compare concepts
• Lab: full-up systems (degrees of freedom) but
subscale dimensions, timescales
• On existing telescopes: fewer degrees of freedom, but
larger dimensions, real atmosphere
Adaptive Optics Road Map
Outcomes: At least two types of AO Systems
Examples:
•
2010-2012: Fund construction of high performance, narrow-field AO system for ELT
application
•
2010-2014: Fund construction of a capable MCAO system for ELT application
•
In both cases, these developments represent the culmination of the roadmap
investments:
–
Integration of challenging & complex components into enabling systems for ELTs
Essential, identifiable NSF investment in ELTs.
Will benefit AO for all existing telescopes.
Adaptive Optics Road Map
Funding Estimates: Historical Background
• Bahcall report recommended $40M for the 1990s
– Total public, private, international support exceeded this
– Multiple approaches were funded
• Appropriate to early R & D effort
– Multiple successful approaches have now been implemented on
current telescopes
• Funding was far less successful in producing robust systems or key new
components
– some installations had small user base
– duplication of effort
– little strategic coordination of investments
• For ELTs we need a better coordinated strategy to enhance the
efficacy of investments, assure that ELT technology requirements
can be met
Adaptive Optics Road Map
Funding Estimates: Next Decade
• Supporting enabling technology for ELTs will require
investing at least $50M (AASC decadal report)
• Integrating these components into capable 30m ELT AO
systems will cost between $75M and $150M
– NIO and CELT design studies
• Numbers indicate the scale of needed investment
– More detailed estimates will be developed in the next
phase of the roadmap process
US investment must approach $10 M / yr
Requires increase over current levels of ~ $5 M / yr
Adaptive Optics Road Map
A Community-based Roadmap Process
• Community involvement; consensus is crucial
• NOAO represents logical focus for engaging the
community and developing needed consensus
• In analogy with the TSIP program, NOAO would
convene periodic meetings of a broad-based AO
steering group in order to:
– seek community feedback on the roadmap
– work with NSF to set up process to evaluate proposals
– evaluate achieved progress against roadmap goals
• As with TSIP, funding could flow through NOAO
– NOAO would not compete for AO funds
Adaptive Optics Road Map
A Community-based Roadmap Process
• An AO steering group would
– Review advances in AO; supporting technologies
– Review the overall pattern of federal investment
– Assess the need for roadmap changes, and modify roadmap as
needed
– Recommend to NSF, and outline ‘announcements of
opportunity’ to encourage proposals in key areas
• Steering group meetings timed to influence NSF budget
priorities; announcements of opportunity
• This process is analogous to that used by the nuclear
science community through NSAC
Adaptive Optics Road Map
A Community-based Roadmap Process
• In parallel, the NSF would
– Actively seek proposals aligned with the roadmap
– Focus funding on strategically important areas
– Review proposals using a broadly-based panel
• Astronomers; government lab scientists; industrial
engineers and scientists
• Panelists would have AO & systems experience
– Provide sustained, long-term funding
• Complex component and technology development require
sustained investments for > 5 years
• TSIP provides a model for planning and funding
• AO funds for ELTs should be held in a ‘separate pot’
– Implementation of AO systems on current telescopes would
come from other programs, not AO-ELT funds
Adaptive Optics Road Map
Desired Outcomes of this Discussion
• CAA support and recommendation for:
– Focused and sustained investment in AO for ELTs
• additional ~ $5M / yr of new funding is needed
– A roadmap-based process to guide such investment as
described above.
Success of AO on 30-m telescopes will require
sustained investment for a decade.
The time to start is now.
Adaptive Optics Road Map