EEM calculations in FRED

Mikkel BrydegaardApplied Molecular Spectroscopy & Remote Sensing

Atomic Physics, LTH

Project

Components

• Fiber tip source

• Off axis parabolic mirror

• Quartz prism

• Achromat

• Sample window

• Chassis

Source

• Ocean Optics ø230 μm circular fiber tip

• 24° acceptance angle

• Apperture to 6° for collimating mirror

• Simulated spectral content: 300, 350, 400, 500 and 900 nm

Collimating mirror

• Newport. Off-Axis Replicated Parabolic Mirror, 1.500 in. Dia, 4.000 in. EFL, Protected Aluminum Coating

Prism

• Esco products

• Equilatheral fused silica

• 40mm sides

• 35° mean dispersion 300-900nm

• 40*cos(30+35/2)=27mm apperture

• Displacement of optical axis from center of circumcicle of prism 8.93 mm

Achromat

• Edmund optics

• Uncoated triplet

• CaF2 Fused Silica CaF2

• Provided raytracing object from edmund upon signed request

Sample slit

• Quartz microscope cover slide

• Mirror coating

• Nano church

Chassis

• Imported from Alibre design

• Anodized aluminum

• Black lambertian 4%

• Contribution

Setup

Fiber tip

Newportv Off-axis paraboloid

EscoQuartzprismQuartz

window

Edmund achromatCaF2-QS

Properties of interest

• Throughput

• Spectral resolution

• Signal to background

Simulation variables

• Ray numbers

• Allow reflections

• Allow surface scatters

Resulting rays

End rays C1 C2 C3

R1 175 3855 24710

R2 2405 66122 430448

R3 14560 418750 2693084

Simulation time

Calculation time C1 C2 C3

R1 0.933 sec 5.94 secs 31.2 secs

R2 6.25 secs 50.2 secs 8.76 mins

R3 35.6 secs 5.23 mins 54.2 mins

Throughput

Throughput C1 C2 C3

R1 56,62% 56,85% 56,85%

R2 60,95% 61,23% 61,23%

R3 61,55% 61,85% 61,85%

FWHM

FWHM mm C1 C2 C3

R1 0.115 0.147 0.147

R2 0.146 0.146 0.146

R3 0.136 0.136 0.136

FWHM nm C1 C2 C3

R1 14.30 18.33 18.33

R2 18.14 18.14 18.14

R3 16.91 16.93 16.93

Added background

Background C1 C2 C3

R1 0,00E+00 4,70E-03 2,16E-04

R2 0,00E+00 1,40E-03 1,65E-05

R3 0,00E+00 9,09E-04 2,73E-06

Signal and back ground contributions

3.5E0 1E-3

3E-6

Spatial profile of background contributions

Experiences

• Prism displacement

• Ommitment of achromat, in accordance with ”Spectrograph design fundamentals / J.F. James.”

• More stray light along slit than perpendicular to it

• Parabolic mirrors in FRED