Statement of Work and Specifications for the Optical Design ... - ATST

950 N. Cherry Avenue, Tucson, Arizona 85719Telephone: (520) 318-8102Fax: (520) 318-8500atst@nso.edu http://atst.nso.edu/Statement of Work and Specifications for the Optical Design and ToleranceAnalysis of the Wavefront Correction High-Order WavefrontSensorRevision:AIssue Date: 14 June 2013Prepared By :Name Signature DateSteve HegwerInstruments ManagerS. Hegwer 17 Jun 2013Approved By :Approved By :Approved By :Approved By:Released By :Sam BardenWFC ManagerHarvey BassContracts ManagerRob HubbardSystems EngineerJoseph McMullinProject ManagerThomas RimmeleProject DirectorS. Barden 17 Jun 2013H. Bass 17 Jun 2013R. Hubbard 17 Jun 2013J. McMullin 24 Jun 2013T. Rimmele 24 Jun 2013

Document: SOW for Design and Analysis for HOWFSRevision: ADate: 14 June, 2013Change Record:Section(s)Revision Date AffectedDescription of ChangeA 21 Mar 2013 All Initial draft for approval and releasePage 2 of 10

Document: SOW for Design and Analysis for HOWFSRevision: ADate: 14 June, 2013Contents1. General Work Description .................................................................................................................... 41.1 Design Optimization Study ........................................................................................................... 41.2 Meetings ........................................................................................................................................ 41.2.1 Meeting Schedule .................................................................................................................. 41.2.2 Meeting Content .................................................................................................................... 41.3 Completion .................................................................................................................................... 52. Deliverables .......................................................................................................................................... 52.1 Reports .......................................................................................................................................... 5- A description of the work performed. ............................................................................................... 5- Optical design description including a requirements compliance matrix . ....................................... 52.2 Contents of the Data Package; Directory or File: ......................................................................... 52.3 ISO Element Drawing Details ...................................................................................................... 6APPENDIX A. SYSTEM DESCRIPTION ............................................................................................. 81. General Description .............................................................................................................................. 72. Conceptual HOWFS Optical Design .................................................................................................... 73. HOWFS Optical Requirements ............................................................................................................. 83.1 Optical Design .............................................................................................................................. 83.2 Wavelength Range ........................................................................................................................ 83.3 Pupil Distortion ............................................................................................................................. 83.4 Pupil Imaging Capability .............................................................................................................. 83.5 Pupil Adjustability ........................................................................................................................ 83.6 Sub-Aperture Field of View .......................................................................................................... 83.7 Sub -Aperture Count ..................................................................................................................... 83.8 Nominal Lenslet Array Configuration and Image Separation ...................................................... 93.8.1 Nominal Lenslet Array Configuration .................................................................................. 93.8.2 Sub-Aperture Image Separation .......................................................................................... 103.9 Plate Scale ................................................................................................................................... 103.10 Plate Scale Adjustability ............................................................................................................. 103.11 Image Distortion ......................................................................................................................... 103.12 Optical Performance at the Detector Plane ................................................................................. 103.13 Total Track .................................................................................................................................. 10Page 3 of 10

Document: SOW for Design and Analysis for HOWFSRevision: ADate: 14 June, 20131. GENERAL WORK DESCRIPTION1.1 DESIGN OPTIMIZATION STUDYThis Statement of Work (SOW) defines the tasks and deliverables that shall be performed and providedby the Contractor. This effort shall be hereinafter referred to as the Work.The Work shall consist of the Contractor reviewing and analyzing the provided Wavefront Correction(WFC) High-Order Wavefront Sensor (HOWFS) conceptual design (see Appendix A),makerecommendations for optimizing the design with respect to: manufacturing feasibility; cost-effectiveness;and likelihood of achieving performance requirements, and develop a final toleranced design based uponthose recommendations and feedback/review by AURA.1.2 MEETINGSContractor shall organize and conduct, at a minimum, the following meetings:1.2.1 Meeting ScheduleTimeT0T0 + 1 weekT0 + 2 weeksT0 + 4 weeksT0 + 6 weeksEvent*AwardKick Off1 st Progress Review Meeting2 nd Progress Review MeetingFinal Design Review MeetingT0 + 8 weeks Final Report MeetingT0 + 9 weeks AURA Report Review periodT0 + 10 weeks Revised Final report due*See Section 1.2.2 for specific meeting content and objectives1.2.2 Meeting ContentKick-off meeting - to discuss the objectives of the Work and to ensure that the requirements are clear andsufficient for the Work to proceed. Contractor shall propose a schedule with a goal of submitting the FinalReport within 8 (eight) weeks from contract award, followed by a one week AURA review period and aone week Contractor response period. The proposed schedule shall include major milestones of theoptical design and tolerance analysis.1 st Progress review meeting - to review the feasibility, status and progress of the optical design.Contractor shall provide preliminary results, identify any remaining issues, a summary of theoutcomes, a preliminary Zemax model for review. and any action items resulting from this meeting.2 nd Progress review meeting - to review the final optical design and review the steps of thetolerancing effort. Contractor shall provide preliminary results, identify any remaining issues, asummary of the outcomes, the final Zemax model for review, and any action items resulting from thismeeting.Page 4 of 10

Document: SOW for Design and Analysis for HOWFSRevision: ADate: 14 June, 2013Final design review meeting - to review the tolerance and sensitivity analysis of the final design.Contractor shall provide results, identify any remaining issues, and shall summarize the outcomes andany action items resulting from the meeting. The intent of the final design review meeting is toidentify any remaining issues or areas requiring further work before the final report can be submittedFinal report meeting - to review the final report. Contractor shall provide a preliminary final report toAURA for review and comment not later than 1 week before the final review meeting. Should AURAfind deficiencies in either the preliminary report or the meeting contents, AURA will return thepreliminary report with comments not later than 1 week following final meeting so as to allow theContractor to take any corrective actions.1.3 COMPLETIONThe Contractor shall complete the Work within the 8 week schedule. Weeks 9 and 10 are reserved forAURA review/comment of the Final Report and the Contractor’s responses, respectively.2. DELIVERABLESThe Contractor shall deliver the following:2.1 REPORTSA preliminary and after revisions, a final report, in electronic format ( i.e. .PDF and/or MS Word) thatshall contain:- A description of the work performed.- Optical design description including a requirements compliance matrix.- Notable analysis features.- Monte Carlo tolerance analysis description, including error distribution assumptions.- Monte Carlo tolerance results indicating the statistical distribution of top level performance and asensitivity analysis in tabular form. This shall include fabrication, mounting, and alignmenttolerances.- Table of compensator ranges.- Conclusion of results and identification of tolerances that significantly increase fabricationrisk,cost, and mounting/alignment complexity- List of contents included in the data package.2.2 CONTENTS OF THE DATA PACKAGE; DIRECTORY OR FILE:- The Zemax optical design file for the final design including a lookup table for the position ofthe triplet lenses as a function of zoom.- A lookup table of the position of the Cooke elements and other components as a function ofzoom.- Drawings directory: contains the optical element drawings in ISO 10110 PDF format.- WFC tolerance models: the Zemax models used to generate the tolerance RMS wavefronterror sensitivities and to run the Monte Carlo analysis. This contains the Zemax ToleranceData Editor table of values.- WFC element drawings: the Zemax models that contains the ISO 10110 element drawings.Page 5 of 10

Document: SOW for Design and Analysis for HOWFSRevision: ADate: 14 June, 2013- Tolerances run listings .txt: the output files generated by running the tolerance analysis in theWFC Zemax tolerance models.- Zemax directory: contains the scripts (.tsc), merit functions (.mf), and dialog settings (.top)used in the analysis.2.3 ISO ELEMENT DRAWING DETAILS- ISO element drawings for the WFC transmission optics shall include AR coatings with

Document: SOW for Design and Analysis for HOWFSRevision: ADate: 14 June, 2013APPENDIX A : SYSTEM DESCRIPTION1. GENERAL DESCRIPTIONAs illustrated in Figure-1, there are four major sub-systems within the WFC optical system that sharecommon feed optics. The common feed optics include the BS-1 beam-splitter, two unique off-axisparabolas (OAP-1 and OAP-2), and two fold mirrors (FM 1 and FM 2). The four sub-systems include: thehigh order wavefront sensor (HOWFS), the low order wavefront sensor (LOWFS), and two contextviewer (CV) configurations.Figure-1 WFC Overview2. CONCEPTUAL HOWFS OPTICAL DESIGNThe figure below is a conceptual design to help convey the approach and requirements. The systembegins at the focal plane located at the 10 arc-sec FOV field stop.The first Cooke triplet in principle collimates the focal plane located at the field stop and produces a pupilwhere the Shack-Hartman lenslet array is placed. Two elements of the first Cooke triplet piston to adjustthe pupil diameter on the lenslet array.The collimator lens collimates the focal planes produced by the lenslet array and acts with the secondCook triplet to produce the desired F# at the camera detector. The collimator shall also collimate the pupil- allowing the 2 nd Cooke triplet to image the pupil on the detector. Two elements of the second Cooketriplet piston to adjust the F# on the detector. This conceptual design requires manual adjustment andrealignment following the Cooke elements piston movements. Note; a VG9 or similar Schott coloredglass filter of approximately 3mm think will be located between the last Cooke triplet and the detector.The optical performance and tolerance analysis shall include this optic.Page 7 of 10

Document: SOW for Design and Analysis for HOWFSRevision: ADate: 14 June, 2013Figure-2 Conceptual Optical Design3. HOWFS OPTICAL REQUIREMENTS3.1 OPTICAL DESIGNThe HOWFS shall be a Shack-Hartmann wavefront sensor.3.2 WAVELENGTH RANGERequirement: 475-575 nm; Goal: 475-600nm.3.3 PUPIL DISTORTIONMaximum distortion introduced between the M10 pupil and the pupil at the HOWFS lenslet array shall beless than 0.11%. The Contractor shall provide a Zemax file that demonstrates compliance.3.4 PUPIL IMAGING CAPABILITYThe collimator lens shall piston to image the pupil and the sub-aperture focal plane images onto thedetector with no adjustment of the second Cooke triplet lens elements and detector piston. The Contractorshall evaluate the feasibility of reversing the position of the collimator and second Cooke triplet lens.Note: The full pupil diameter on the detector should not exceed the active sensor dimension of 11 mm,but be sufficiently large to image the lenslet array.3.5 PUPIL ADJUSTABILITYThe pupil size on the HOWFS lenslet array shall be adjustable to within 15% of its nominal value usingthe 1 st Cooke triplet.3.6 SUB-APERTURE FIELD OF VIEWEach sub-aperture of the HOWFS shall have a FOV of 10 0.5 arc seconds.3.7 SUB -APERTURE COUNTThe HOWFS shall contain 43 fully-illuminated subapertures across the pupil diameter, resulting in a totalof 1405 fully-illuminated subapertures. For purposes of this requirement, a fully-illuminated subapertureis defined as a subaperture whose active lenslet area is ≥ 90% filled by the telescope pupil.Page 8 of 10

Document: SOW for Design and Analysis for HOWFSRevision: ADate: 14 June, 2013Figure-3 Sub-apertures3.8 NOMINAL LENSLET ARRAY CONFIGURATION AND IMAGE SEPARATION3.8.1 Nominal Lenslet Array ConfigurationThe nominal focal length of the lenslets shall be 56 mm, +/- 1.5mm.The nominal diameter of the lenslets shall be 0.5mm. The tolerance on lens diameter and position are submicron.The Contractor may recommend a departure from the nominal focal length and diameter. The followingformula shall be used to derive a configuration:Focal length = ATST optical invariant * # sub-apertures * pitch diameter ^2/ FOVATST optical invariant = 51.5#sub-apertures = 43.2FOV = 10 arc-secondsPage 9 of 10

Document: SOW for Design and Analysis for HOWFSRevision: ADate: 14 June, 2013FL mm = 51.5 * 43.2* 0.5^2/10 = 55.62 mm (round to zero decimals for manufacturing)3.8.2 Sub-Aperture Image SeparationSub-aperture images at the detector plane of the HOWFS shall not overlap each other, nor shall any twoadjacent sub-aperture images be separated by more than one pixel (11.5 microns).3.9 PLATE SCALEThe final focal plane of the HOWFS shall have a plate scale of 43.48 2.17 arc seconds per mm.Note: the HOWFS camera has 11.5 micron square pixels and each sub-aperture has a 10 arc secondsquare field of view. To obtain 20 pixels across each sub-aperture, the final plate scale must be (100.5)/(20 *11.5e-3) = 43.48 2.17 arc seconds/mm.3.10 PLATE SCALE ADJUSTABILITYThe plate scale at the final focal plane of the HOWFS shall be adjustable to within +/- 15% of its nominalvalue.3.11 IMAGE DISTORTIONMaximum distortion introduced between the lenslet array focal plane and the detector focal plane shall beless than 0.11%.3.12 OPTICAL PERFORMANCE AT THE DETECTOR PLANEThe detector plane Strehl in each sub-aperture shall be > 0.9 @ 480-nm3.13 TOTAL TRACKThe final detector plane of the HOWFS shall be no more than 1.5 meters from the HOWFS field stop.Page 10 of 10