Interference colors of thin films (V2.7)


This script calculates the interference colours, which appear upon reflection at substrates coated with a thin, transparent, and dielectric film.
The colours can be plotted against the film thickness or the angle of incidence. Because of the limited colour space of the display, some of the calculated colours cannot be displayed correctly. In this case the colour will be mixed with white and discoloured until it reaches the edge of the sRGB colour space.
Consideration of dispersion is provided by two different sets of formulas for cauchy layers (λ, γ in nm):

Model   n(λ)   k(λ)
Sentech n0+102n1/λ2+107n2/λ4 k0+102k1/λ2+107k2/λ4
Woollam n0+106n1/λ2+1012n2/λ4 Akexp(124000*Bk*(1/λ-1/γ))

Coating parameters

Refractive index of the coating   n0=   n1=   n2=
Cauchy layer (Sentech ellipsometers) k0=   k1=   k2=
Cauchy layer (Woollam ellipsometers) Ak=   Bk=   γ= nm
Predefined material  
 
Minimum film thickness   = nm
Maximum film thickness   = nm
 

Substrate parameters

Refractive index of the substrate   n0=   n1=   n2=
Cauchy layer (Sentech ellipsometers) k0=   k1=   k2=
Cauchy layer (Woollam ellipsometers) Ak=   Bk=   γ= nm
Predefined material  
 

Environment

Lightsource Black body radiation with a colour temperature of K
 
 

Colour display

Spectrum normalize for maximum intensity
Colours outside the displays colour space discolour individually
discolour individually and show a red mark
  discolour whole spectrum until all colours can be displayed

Colour scale depending on the film thickness
Colour scale depending on the angle of incidence for a film with a thickness ofnm
2D colour scale depending on angle of incidence and film thickness.
The angle increases from 0 to 90° from top to bottom.
Resolution for angle axisPixels
Resolution for thickness axisPixels

The calculation of a high resolution 2D colour plot may be quite time consuming. Browsers may interrupt the calculation with a dialog box and ask if the script should be stopped.