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Refractive index n of InxGa1-xAs alloys

Contents  
   
 
Equation  
 

Using the Sellmeier equation for GaAs a simple model based on the shift of the band gap energy Eg(x) of the InxGa1-xAs alloy leeds to the expression:

 
 
  Formula refractive index of InGaAs eq.(1)  
 
  with  
 
  Formula  
  down
  In this equations the symbols and constants have the following meaning in the case of InXGa1-XAs alloys at room temperature (T = 300 K):
 
       n(x) (real part) of the refractive index  
       A = 8.950 empirical coefficient  
       B = 2.054 empirical coefficient  
       C = 0.6245 empirical coefficient  
       x   In fraction in the InXGa1-XAs alloy  
       EgGaAs = 1.424 eV fundamental band gap of GaAs at room temperature (300 K)  
       l light wavelength in the vacuum in µm  
 
Graph up
 
 

Graphs with calculated refractive indices of InXGa1-XAs alloys as a function of the wavelength l for x-compositions from 0 (magenta) to 0.9 (black) with step differences of Dx = 0.1.

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  Index of refraction n(InGaAs)
 
Table with numerical values  
 
  calculator calculator for n(x,l)   (uses javascript)  
 
 

Refractive index n of GaAs calculated with eq. (1)

 
 
 
l
(nm)
n(InXGa1-XAs)
x=0 x=0.1 x=0.2 x=0.3 x=0.4 x=0.5 x=0.6 x=0.7
900 3.593 3.639 - - - - - -
950 3.545 3.658 - - - - - -
1000 3.510 3.596 - - - - - -
1100 3.461 3.517 3.615 - - - - -
1200 3.431 3.471 3.536 3.657 - - - -
1300 3.409 3.439 3.487 3.568 - - - -
1400 3.393 3.418 3.454 3.513 3.619 - - -
1500 3.382 3.401 3.429 3.474 3.552 - - -
1600 3.372 3.388 3.412 3.448 3.507 3.619 - -
1700 3.366 3.379 3.399 3.428 3.476 3.558 - -
1800 3.360 3.372 3.388 3.413 3.451 3.517 3.647 -
1900 3.354 3.365 3.379 3.400 3.432 3.486 3.585 -
2000 3.351 3.360 3.372 3.390 3.418 3.461 3.541 3.712
2200 3.344 3.351 3.362 3.375 3.396 3.428 3.483 3.586
2400 3.339 3.345 3.354 3.365 3.381 3.406 3.445 3.517
2600 3.336 3.341 3.348 3.357 3.370 3.390 3.421 3.473
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