absorber coatings for mid-infrared astrophysics · observational cosmology lab, nasa goddard space...
TRANSCRIPT
ABSORBERCOATINGSFORMID-INFRAREDASTROPHYSICS
DAHLIABAKER1,EDWARDWOLLACK2 ,KARWAN ROSTEM2,3
1.COECOLLEGE,DEPARTMENTOFPHYSICS
2.OBSERVATIONALCOSMOLOGYLAB,NASAGODDARDSPACEFLIGHTCENTER
3.DEPARTMENTOFPHYSICSANDASTRONOMY,THEJOHNSHOPKINSUNIVERSITY
• PhysicsandMathematicMajor
• PhysicsClubandOutreach
• StudiedComputationalBiophysics,movingontoPlanetaryScienceresearch
ABOUTME
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BACKGROUND
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• HIRMES- HighResolutionMid-InfrarEd Spectrometer• Functioninginthe20-200micrometerrange
• Eliminate
• SOFIA– StratosphericObservatoryforInfraredAstronomy
APPROACH• Goals
• Createamaterialthatabsorbsstraylight• Lightweight,easyapplicable• Knowndielectricfunction
• Whatisthis?Describestheelectricresponsetoincidentradiation
• Diffusivelyreflectsratherthanspecularly reflects• Withstandcryogenictemperatures(µK)
• FirstStep- Characterizethematerials• Dielectricfunctions
• SecondStep- Matlab Model• Modeleachsamplelayerwithfounddielectricfunction
• ThirdStep- Manufacturing• Createsampleplates
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APPROACH
3MGlassMicrospheres~100micronsindiameter
Epotech 377HGraphene- LoadedEpoxysC(5):377(65):SiOx(30)
Aeroglaze Z306
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Specular Diffuse
SAMPLES
SampleLetter
ThicknessofEpoxy(µm) FinalLayerCount Composition(LayerOrder)
A 579 2 Epoxy,Z306B 644 3 Epoxy,Z306,K1C 449 3 Epoxy,K1,Z306D 505 4 Epoxy,K1,Z306,K1E 707 1 EpoxyF 494 2 Epoxy,K1
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DIELECTRICCHARACTERIZATION
Frequency (GHz) 22 26 30 34 38 42
Res
pons
e (d
B)
-40
-30
-20
-10
0
WR28.0 Sampleholder: K1 Microspheres
Average: S11 & S22Theory: S11, S22Average: S12 & S21Theory: S12, S21
Ø Frequencyresponsedatatakenwithamicrowavenetworkvectoranalyzer
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TransmissionthroughwaveguideReflectionfromsample
• Periodicstructureofreflectionshowsconstructiveanddestructiveinterference
• Showsthe“truedensity”asseenbyanincidentelectromagneticwave
• Lossisduetodielectricpropertiesofmicrospheres,scatteringduetogeometryisnotconsidered
THEMODEL
Material Thickness(µm) Dielectric(-)
Aluminum 500 1+1x108i
Epoxy377H 500 7.4+0.4i3MK1
Microspheres 100 1.1 +0.002i
Aeroglaze Z306 50 2.6+0.6i
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Responsevs.Wavelength
RESULTS
• Conclusions• Ourproposedmaterialcanbe
manufacturedatasmallscale• Modelpredictscorrectresponse• Drawback– modelcannotpredict
responsefromdiffusescatteringduetomicrospheres
• FurtherStudies• Measureoptical
frequency-dependentresponsewithaFourierTransformSpectrometer
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Transmittancevs.FrequencyforEpoxy
Reflectancevs.FrequencyforEpoxy
ACKNOWLEDGEMENTS
CoeCollegeAdvisors
SteveFeller Ugur Akgun Firdevs Duru MarioAffatigato
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ACKNOWLEDGEMENTS
AIP/SPS
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ACKNOWLEDGEMENTS
NASAandCollaboratorsIwouldliketogivespecialthankstotheObservational
CosmologyLabatNASAGoddardSpaceFlightCenterandmymentors
EdwardJ.Wollack Karwan Rostem
Fortheirsupportofmyproject:
• DaveChuss andRileyMcCarten,VillanovaUniversity
• PaulMirel,ObservationalCosmologyLab,NASAGSFC
• KyleJohnson,GeorgeWashingtonUniversity
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