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Refractive index n of InGaAs

Equation

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

Formula refractive index of InGaAs
with

Formula

IIn this equations the symbols and constants have the following meaning in the case of InXGa1-XAs alloys at room temperature (T = 300 K):

  • n - (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)
  • λ - vacuum wavelength [µm]

Numerical values

  calculator Calculator for n(x,λ)   (uses javascript)

Graph with calculated refractive index of InXGa1-XAs alloys as a function of wavelength λ for x-compositions from 0 (magenta) to 0.9 (black) with step differences of Δx = 0.1.

Graph n(x,λ)

Table with calculated values for refractive index n

Calculated real part of refractive index  n(InXGa1-XAs) at T = 300 K

λ (nm) 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