Abstract

Accurate knowledge of the refractive index, n, of optical materials is required for the development of many optical devices in the visible (VIS), near- (NIR) and mid-infrared (MIR) spectral regions, such as lasers, light-emitting and super-luminescent diodes, and distributed Bragg reflectors (DBRs). Typically, n shows a variability depending on deposition conditions, which motivates the need for routine characterization of as-produced structures. While several measurement methods for n exist, among them (spectroscopic) ellipsometry and Fourier-transform infrared (FTIR) refractometry, they all come with their (dis-)advantages, e.g., accurate goniometric measurements or highresolution FTIR [1].

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