WBS%203.3%20Laser%20Facility

1
WBS 3.3 Laser Facility

• Jim Bell, Jason Chin, Erik Johansson, Chris
  Neyman, Viswa Velur
• Design Meeting (Team meeting 11)
• November 05, 2007

2
Agenda

• Discussions at CfAO retreat on Sodium Return
• Feasibility of SOR and LMCTI lasers
• Other progress

3
Sodium Returns

• Sodium Return
• Discussions at CfAO shows there are still large
  uncertainties in determining sodium returns.
• The best data we have currently comes from the
  SOR and the Gemini North System.
• Circular polarization factor is diminished by
  Mauna Keas latitude as compared to SOR. The 2x
  factor may be closer to that of GNs 1.3.
• SORs next generation dual frequency pump laser
  of D2a and D2b will increase return by a factor
  of 1.6.

4
Laser Architectures

• Stable Laser Platform (SLP)
• Laser is on or below the Nasmyth Platform.
• No dependency on a moving gravity vector.
• More complex laser beam transport system, use of
  fibers, likely more throughput losses.
• Moving Laser Platform (MLP)
• Laser is on the elevation ring.
• Dependency on a moving gravity vector.
• Added complexity for installation on the
  elevation ring.
• Improved throughput.

5
Whats happening at SOR?

• Current AFRL plans
• In process of fabricating a new and improved SOR
  unit.
• New SOR system is expected to see improvements in
  power, 50.
• Redesign of optical bench to include modular
  design. Modular design of amplifiers will
  provide additional stability and simplicity.
  Reduce size of optical bench but likely increase
  due to double pumping.
• Improvement in the NPRO engine for higher output.
• Removal of OTS units for better stability.
• No plans for a gravity moving vector system but
  expects the new redesigns and modules to be able
  to handle a changing gravity vector.
• Improvement to stability using hallowed out
  machined mechanical blocks.
• Second system for Maui will be more similar to
  the existing system than new system. SOR will
  used 14 existing NPRO engines.
• Funding of the Maui System is not concrete. A
  laser is expected as part of the new AO system at
  for Maui.
• Maui system will not have a changing gravity
  vector although optical bench is vertical.
• AFRL currently moving forward with design of new
  SOR system.

6
SOR Feasibility

• Using SORs system with a MLP architecture.
• High power supplies in thermal enclosure on the
  Nasmyth Platform.
• Large gauge low voltage high current power cables
  from Nas Platform to elevation ring (200 ft
  maximum).
• Elevation ring will include two 3x8 thermally
  controlled optical benches and electronics
  controller. Size of this enclosure will be
  similar to the K2 laser enclosure on the
  telescope.
• Sealed systems for condensation considerations
  No need for clean room.
• Will require 16KW to 20KW for power and heat
  removal.
• AFRL expects to complete the SOR and Maui system
  by 2010.
• Fits into NGAOs timeline for procurement of
  laser in 2010.
• Possible collaboration effort

7
LMCTI Feasibility

• LMCTI is focused on finishing GSK lasers.
• Discussions suggest some minor reduction in size
  of the current system but not likely to be
  significantly different without additional
  funding.
• System architecture will be similar to K1 using
  the SLP architecture.
• Will require large enclosure on or below Nasmyth
  Platform to house multiple laser benches and
  electronics racks.

8
The F Factor

• Fiber Lasers
• ESO is developing fiber laser internally and
  externally with manufacturer (Volius in Moscow).
  4 lasers to be installed on the VLT.
• Currently 5Watts. Expects power to double by
  Jan 08.
• Once power levels are met, technology will be
  transferred to engineering company in Europe.
• Product will be available to all.

9
WBS 3.3 Laser

• Progress
• Draft Laser Architecture Report on Twiki. Needs
  update with recent CfAO discussions.
• Laser Enclosure Requirements Updated
• Laser Requirements Upated.
• Block Diagram for laser control system updated.
  Start specifying the blocks and interfaces.