Abstract

There is a wide variety of methods for determination of the optical functions N(λ)=n(λ)+ik(λ) or ε(w)=ε₁(ω)+iε₂(ω), often named "constants", from experimental measurements.¹ The methods can be split into two main categories a) One measurement over an extended wavelength range and b) two (or more) measurements at a single wavelength. The physical basis for this division is that the values of the two functions are independent at each isolated wavelength, but there is an integral relationship between the two functions over the entire wavelength range. This is exploited in methods of category a) where typically Kramers-Kronig calculations of bulk reflectance are used to calculate the phase of the complex reflectance amplitude and then N(λ) or ε(ω) are calculated from closed expressions.² In category b-methods, no relationship between the two functions is used and then at least two measurements are needed at each wavelength.

© 1998 Optical Society of America