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## Refractive index n of AlGaAs

### Equation

According to Sadao Adachi J. Appl. Phys. Vol. 58, No.3, (1985) R1 the real part of the refractive index n of a zinkblende material below the direct band gap edge can be expressed due to a simplified interband-transition model as:

with

In this equation the symbols and constants have the following meaning in the case of AlxGa1-xAs at room temperature:

• n - (real part) of the refractive index
• λ - vacuum wavelength
• h = 6.626 10 -34 Js - PlanckĀ“s constant
• c = 2.998 108 m/s - speed of light in vacuum
• hc/λ - photon energy
• A0(x) = 6.3 + 19.0 x - fitted constant
• B0(x) = 9.4 - 10.2 x - fitted constant
• x - Al fraction in the AlXGa1-XAs alloy
• E0(x) = 1.425 + 1.155 x + 0.37 x2 [eV] - fundamental band gap at Γ-point
• E0(x) + Δ0(x) = 1.765 + 1.115 x + 0.37 x2 [eV] - spin-orbit splitting energy

### Numerical values

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

Graphs with calculated refractive indices of AlXGa1-XAs alloys

#### Table with calculated values for refractive index n

Calculated real part of refractive index  n(AlXGa1-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 x=0.8 x=0.9 x=1.0
800 - - 3.551 3.468 3.396 3.332 3.265 3.208 3.141 3.085 3.023
850 - 3.572 3.491 3.423 3.362 3.305 3.240 3.186 3.119 3.061 2.995
900 3.597 3.519 3.455 3.396 3.336 3.277 3.217 3.164 3.106 3.047 2.991
950 3.544 3.486 3.428 3.370 3.315 3.260 3.203 3.148 3.081 3.036 2.973
1000 3.516 3.463 3.410 3.356 3.305 3.245 3.192 3.137 3.068 3.011 2.972
1050 3.497 3.445 3.393 3.342 3.286 3.231 3.178 3.128 3.062 3.002 2.972
1100 3.483 3.434 3.382 3.335 3.273 3.225 3.167 3.114 3.062 3.001 2.968
1150 3.470 3.425 3.372 3.320 3.268 3.217 3.160 3.120 3.055 3.000 2.957
1200 3.464 3.415 3.366 3.314 3.265 3.206 3.154 3.100 3.045 2.994 2.938
1250 3.457 3.407 3.356 3.308 3.253 3.200 3.156 3.089 3.044 2.982 2.932
1300 3.450 3.401 3.354 3.303 3.245 3.202 3.149 3.089 3.034 2.972 2.926
1500 3.434 3.385 3.332 3.289 3.230 3.184 3.133 3.099 3.011 2.951 2.937
2000 3.418 3.366 3.311 3.268 3.223 3.173 3.127 3.056 2.965 2.951 2.915