PA&C PDR: Op+cal Stacey Sueoka June 8-9, 2016 1 Mee+ng GOS - - PowerPoint PPT Presentation

PA&C PDR: Op+cal

Stacey Sueoka June 8-9, 2016

1

Mee+ng GOS DRD Op+cal Requirements for the calibra+on linear polarizer and retarder

• Calibra+on Op+cal Element:

– 3.1.5 Wavelength range – 3.1.6 Beam Deflec+on – 3.1.7 Coa+ng absorp+on – 3.1.8 Op+cal polish – 3.1.13 Wavefront error – 3.1.14 Opera+ng temperatures

• Calibra+on Linear Polarizer:

– 3.1.15 Aperture – 3.1.16 Reflec+vity &transmission – 3.1.17 Thermal stability – 3.1.19 Ex+nc+on ra+o

• Calibra+on Retarder:

– 3.1.20 Aperture – 3.1.21 Reflec+vity & transmission – 3.1.22 Retarder plate thickness – 3.1.23 Linear retardance & clocking – 3.1.26 Retarda+on – 3.1.27 Thermal stability

SAR/PCM design history and fabrica+on update

• Contract in place with Meadowlark Op+cs Inc. to

build the 3 calibra+on retarders and 3 modulators

March 2015 Acceptance Tes+ng

• AR coa+ng absorp+on
• Clocking error

NSO Laboratory Spectro-Polarimeter

Setup: Polariza+on components

5 5

9 10 6 7 8

6) Calibra+on polarizer 7) Calibra+on retarder 8) Sample 9) Modulator 10) Analyzer polarizer

Mueller Matrix measurements and fit

• Fit for the fast axis orienta+on of each pair
• It was determined that and were the correct clocking

angles, but was rotated by .

!" !! !"#$, !! . !" !! !"#$, !! . !" !! !"#$, !! !! !! !! 90°

Mueller matrix measurements from 400 to 2000nm Blue points are measured results Red curve is the design Red curve is the fit

Meadowlark progress update and +meline

• Polishing: Completed for all plates

except the last few MgF2 plates for Cryo-NIRSP

• AR coa/ng: Strip and recoat
• Clocking/chording: Test in prototype

mount before final assembly

• July/Aug.: DKIST team tests clocking
• Sept.: Receive final assemblies,

perform acceptance tests

Calibra+on retarder thermal

• Opera+onal thermal stability

– Used thermal FEM to derive usable dura+on due to thermal effects

Bulk and gradient temperature effects

DL-NIRSP and ViSP Calibra+on Retarders

• Bulk temperature rise of 4C

– Polarizer in

• Worse coa+ng absorp+on,

> 20 min

• Befer coa+ng absorp+on,

> 40 min

– Polarizer out

• Worse coa+ng absorp+on,

> 5 min

• Befer coa+ng absorp+on,

> 7 min

• Thermal gradient

– Established >80% of steady-state amplitude in < 4 minutes – Polarizer in, both coa+ng cases, ~0.2C gradient – Polarizer out, both coa+ng cases, ~0.75C gradient

Cryo-NIRSP Calibra+on Retarder

• Bulk temperature rise with polarizer in is negligible, out is ~2C
• Thermal gradient TBD pending analysis of recent thermal FEM

Calibra+on Linear Polarizer

• Moxtek wire grid polarizer

– 1mm substrate

• Infrasil

– UVT240A overcoat to protect from oxida+on » Working with Moxtek, trying conformal aluminum oxide

• vercoat which DOES NOT degrade the contrast ra+o
• Sapphire ROM Quote $8.5K

– Great for Cryo-NIRSP, but not a heat stop for quartz like infrasil

Calibra+on polarizer thermal

• Survival temperature: >>200C
• Opera+onal temperature 200C
• Expected temperature ~70C

– Aluminum wires absorb – Infrasil absorbs IR

Ar+ficial Light Source Design

• Previous study performed to select the source:

– Super con+nuum laser vs arc lamp source

• Conclusion: Arc lamp is the chosen source

– Study men+ons as one of several reasons to choose the arc lamp is “the beam diverges from the LASER at a F/# that varies as a func+on of

• wavelength. ”

Mee+ng GOS DRD Op+cal requirements for the Ar+ficial Light Source

– 3.1.28 Ar+ficial broadband light source

• 3.1.28.1 Power
• 3.1.28.2 Uniformity

– 3.1.28.3 Stability

Light feed design in Zemax