150 likes | 333 Views
Original datas : Fiber bundle @ focal plane of F/5,5 telescope primary focal plane - TBC Telescope FOV : 15’x15’ TBC Spatial resolution : 18 arcsec (1 µlens @ focal plane) Spectral resolution : 100 Detector : 1024x1024. Manpower : D.Horville : Optical Engineer
E N D
Original datas : Fiber bundle @ focal plane of F/5,5 telescope primary focal plane - TBC Telescope FOV : 15’x15’ TBC Spatial resolution : 18 arcsec (1 µlens @ focal plane) Spectral resolution : 100 Detector : 1024x1024
Manpower : • D.Horville : Optical Engineer • - Design and fabrication of anamorphoser for GIRAFFE spectrograph • On ESO Very Large Telescope • - Desing and fabrication of an Optical Anamorphoser for X-shooter on VLT • Zemax user, mathematica,Mathcad • B.Lecomte : Technology Engineer • Characterization of A prototype of spectrograph for FUEGOS (GIRAFFE) • Characterization of fiber FRD on several fibers • Technology design, fabrication and delivering of Band 1 detector for HIFI instrument on Herschel space telescope (launch : 2008) • Inventor 11 and zemax user (recent).
Supplier : • Le verre Fluoré (Rennes, France) • Fabrication of IRSIS anamorphoser • Developement and fabrication of IR µlenses matrix. • Prototype of µlens matrix already done quality TB improved. • Confidant with assimbling bundle procedure. • Wait for «frozen » prototype ordering. • How many fibers and µlens
Micro-lenses • Criterii : • micro-lens f length : Short exit pupil of telescope @ infinity. • F ratio of beam focused by µlens > F number of µlens. • µlens diameter> fiber diameter (core+cladding) • Image pupil diameter < Micro-lens core
Bundle entrance Square lenses FL FL Fcore Fcore Fe Wt We n µlens pitch e Fe= 0,95*Fcore µlens pitch = FL/1,414 Hexagonal lenses Fiber diameter(core+cladding)< µlens FL µlens pitch = 2*FL/rac(3)
Entrance µlens charactéristics (calculus) Telescope = diam.300mm Aperture = F/12 Fiber diameter = 100 µm Lens diameter = 315 µm µlens radius of curv. = 2.3mm Dimensions available for commercial fabrication. Check feasibility with infrared materials
Fcladding 180µm Fbuffer 200µm Fiber description IR guide type 3 Fcore 100µm Core index : 1,49 @ 2µm Cladding index : 1,4765 @ 2µm (NA = 0,2) Cladding thickness : 40µm Buffer material : acrylate TBC Buffer thickness : 5 or 10µm Buffer cannot be removed (fiber protection)
Optimization : Bundle output Parameters : Optim : -lens radius of curvature -Thickness of µlens Fixed Files : -Fiber diameter : 100 µm -Output NA : 0,2 -Spectro input apert : F/5 µlens diameter : 295µm 200µ 760µm 432µm
Bundle output : conclusions Slit quality is strongly dependant of : Spectrograph aperture Entrance F/5 : a good choice Shape of lens convexe face Ellipsoïdal lens Vs Spherical
Is it a strong goal having a well define slit ? Low resolution = relax slit quality? D R ?
How to separate lower band and higher band? Duplicate fiber output?(feasibility, transmission?) Infrared Dichroïc (losses?)
Spectrograph : Czerny Turner type F/5 entrance. Parabolic off axis mirrors Serious Optimization TBDone
Strong needs of frozen parameters Accurate optimization Files for bundle and test bench fabrication Nb of fibers, µlens dimensions, slit length
Thermal model? ISRO, TIPR, CNRS,CNES? Mechanical design? LeV.Fluoré / interfaces (TIPR/CNRS)
Test Bench Transmission, quality Qualification Vibration, thermal cycling, cooling