Complex Index of Refraction of Silicon and GaAs

Here is the complex index of referaction of Silicon (from Handbook of Optical Constants of Solids (E.D. Palik))

$Complex index of refraction of Si$

Note that the imaginary part k increases as soon as the wavelength is small enough for band-to-band absorption processes; i.e. h · n > E_G applied (with E_G = band gap).

Here is the dielectric function and the complex index of refraction for GaAs.

Note that several groups actually calculated those curves and that they match rather nicely with the measured values.

$Complex dielectric function and index of refraction of GaAs$

With frame

5.2.3 The Complex Index of Refraction

Exercise 5.2.3 Attenuation of Light

Solution to 5.2-3: Attenuation of Light