Optical constants of Kapton
Kawka and Buckius 2001: n 1.44-4.97 µm, k 1.82-4.98 µm
Complex refractive index (n+ik)
Derived optical constants
Fourier transform infrared (FTIR) spectroscopy is used to measure the bidirectional reflectivity of polyimide films on gold substrates in the infrared. The optical constants of cured polyimide are determined in the infrared region using a Lorentz model to characterize the absorption bands.
P.A. Kawka, R.O. Buckius. Optical Properties of Polyimide Films in the Infrared. Int. J. Thermophys. 22, 517–534 (2001)