Unified analytical inversion of reflectometric and ellipsometric data of absorbing media

We present a unified two-step analytical inversion of reflectometric and ellipsometric data of absorbing media. Instead of a direct determination of the optical constants n, kappa from reflectometric or ellipsometric measurements, we first calculate the real and the imaginary part eta, gamma of the normal component of the wave vector in the absorbing medium. New and simple analytical formulas are obtained for eta and gamma in terms of rho(s), rho(p) or tan psi, delta, respectively, where rho(s), rho(p) and tan psi, delta are the measured reflectometric and ellipsometric parameters of the absorbing medium. The optical constants are then easily determined analytically again from eta, gamma. We use the new formulas to compare the sensitivity with experimental errors due to the inversion of reflectometric and ellipsometric data.