P3K Stimulus Design Update

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P3K Stimulus Design Update

• Rick Burruss
• P3K Team Meeting 7
• February 27, 2008

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Current Stimulus
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Requirements Overview

• Highlights from the Stimulus Requirement Document
  (StRD) version 1.1 (12/11/07)
• There shall be a source that produces light over
  the entire spectrum used by the instrument
  (0.4-2.2um) that can be located at the equivalent
  of the telescope image plane (Science source)
• There shall be a source that produces light at
  589nm /-10nm that can be located at the
  equivalent of 90km focus (LGS source)
  P3K-IRD-0465
• There shall be a source that is bright enough to
  be visible to the eye at full beam size (4.5
  diameter) that can be located at the equivalent
  of the telescope image plane (Alignment Mode)
• At least one source shall have a pupil stop at
  the location of the telescope pupil image
• The Science source shall be adjustable in focus
  by /-25mm
• The Science source shall have a translation range
  of /- 10mm in the x and y directions
• The LGS source should be adjustable in focus from
  the equivalent of 80 to 120km
• Stimulus shall have a seeing-size effective spot
  size of 0.5-1 for NGS
• All sources shall have variable intensity
• The stimulus package shall be configured such
  that the LGS and Science sources can be used at
  the same time
• The stimulus package shall fit within current box

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Optical Design Top View
White Light Aerotech Stages X, Y, Z
594 Laser Aerotech Z Stage
8020 Beamsplitter
OAP1
Beam Entrance Hole (old fold mirror)
Pupil Mask Flipper
FM2
FM1
OAP2
Conjugate Telescope Focus
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The New P3K Stimulus

• All reflective design pupil shared by all 3
  sources
• We will re-use 3 pieces of the current stimulus
• The white light source and fiber in the rack
• The HeNe alignment laser
• The fold mirror (and Newport motor) on the AO
  bench will be retained in its current location
  and height
• All other pieces in the current stimulus package
  will be removed
• We will build the new stimulus package on a
  duplicate breadboard (24 x 24) at JPL
• Work will be done by April 9, May 9 at latest

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Rack Design Front View
New additions are in RED
Newport Versastar 0.5 filter wheel
?c 460 nm
?c 1550 nm
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Light Source Issues

• White Light Source magnitudes
• R-band (WFS) 2.3
• K-band (Pharo) -0.3
• The new white light will be 30 fainter than the
  old white light due to beamsplitter and
  reflective surface loss
• The 632 nm alignment laser will project in multi
  mode when using the white light fiber (2 lobes in
  V-band), although most of the light (gt85)
  remains in the core of the fiber output.
• The 632 nm alignment laser may be used as a
  single mode alignment source through the 594 nm
  laser fiber with the 594 fiber output Aerotech
  stage set to 0 km.
• The 2 laser source intensities may be reduced by
  using a combination of neutral density filters
  mounted in a manually selectable filter wheel
  placed at the output of both lasers.

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594 and 632 Magnitudes
For the 594 and 632 nm laser magnitudes of the
new design, we calculated the overfill loss at
the pupil in the stimulus, assumed 20 loss at
the fiber couple, 2 loss at each optical
surface, and an 8020 beam splitter at the 594
nm input
Source Fiber Used (mode) ND Used Mag _at_ WFS
594 594 (single) None -8.5
594 594 (single) 4.0 1.5
594 594 (single) 4.0 2.0 6.5
594 594 (single) 4.0 3.0 9.0
594 594 (single) 4.0 4.0 11.5
632 594 (single) None -9.6
632 594 (single) 4.0 4.0 10.4
632 White Light (multi) None -9.3
632 White Light (multi) 4.0 4.0 10.7
The 594 nm laser stage must be moved to 0 km
for 632 source alignment
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Science Focal Spot Diagrams

• 450 to 2200 nm Spot Diagram at center, /- 1 mm,
  and /- 10 mm

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Alignment Tolerances

• Stimulus source total wavefront error requirement
• 300 nm / (2)1/2 212 nm
• OAP vendor (B-Con) guarantees ?/4 with best
  effort to ?/8. ?/4 OAP fabrication surface error
  results in 112 nm wavefront error for 2 OAPs
• Final wavefront error
• (alignment errors)2 (fabrication
  errors)21/2 212 nm
• Wavefront error from alignment will not exceed
  180 nm to satisfy total wavefront error
  requirement

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Cable / Controller Additions

• The existing Aerotech EPAQ controller will be
  modified to run 7 stages (it currently controls 3
  stages)
• The 4 new Aerotech stages in the stimulus will
  connect to the existing Aerotech controller via 4
  10 meter cables, which will be bundled together

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Stimulus Cover
Handles
Pupil Access
Output opening
Side Pupil Access
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Final Cost List
Name Quantity Vendor Cost
2 OAP mirrors 2 B-Con (total) 6750
X,Y stages (ATS-50-25) 2 Aerotech (total) 8295
460 nm cutoff fibers (2 m and 5 m) 2 Thorlabs (total) 166
460 nm cutoff fiber (10 m) 2 Thorlabs (total) 336
ND filter wheel hub 1 Newport 109
ND holders (12.7mm diam x 10 mm thick) 5 Newport (total) 145
2.0 ND filter (12.7 mm diam x 2 mm thick) 1 Thorlabs 20
3.0 ND filter (12.7 mm diam x 2 mm thick) 1 Thorlabs 20
4.0 ND filter (12.7 mm diam x 2 mm thick) 5 Thorlabs (total) 100
OAP Gimbal Mounts (Bartos - FQPM) 2 In House (total) 500
8020 beamsplitter 1 CVI 310
Fiber Coupling Hardware 1 Thorlabs 516
Pupil flipper mount 1 NewFocus 248
Mechanical Fabrication of Pupil Mask 1 JPL (Bartos) 200?
Mechanical Fabrication of Cover 1 Caltech (Bui) 2000?
Mechanical Fabrication of Cover Total Total 19715
Items in hand are green, items on order are blue
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Pencil Beam

• A pencil beam laser source, a fold mirror, and a
  magnetic kinematic mount will be permanently
  added outside of the stimulus cover for AO lab
  testing. These additions will not vignette any
  part of the stimulus beam nor will they block the
  off-axis relay mounts. The second fold mirror
  will be permanently fixed to the magnetic mounts
  twin for quick and easy assembly.

Permanent Mount
Temporary Fold
Permanent Fold
Permanent Laser
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Phase Screens

• During the design review, CD jewel case covers
  were suggested as a simple cost-effective method
  to generate various spot size disks in the output
  beam of the stimulus.
• Once the stimulus is working, we can try this
• The 6 diameter door on the top of the cover
  should allow easy access and jewel case placement
  (pieces of plexi-glass?)