New type of ellipsometry in infrared spectroscopy: The double-reference method

TL;DR

This paper introduces a novel infrared ellipsometry method that measures the complex refractive index directly using double-reference reflectivity, simplifying the process and broadening spectral applicability.

Contribution

It presents a new ellipsometry technique that determines complex refractive index without Kramers-Kronig transformation, utilizing a double-reference approach with diamond as a reference.

Findings

Direct measurement of complex refractive index without Kramers-Kronig transformation

Broad spectral range from far-infrared to ultraviolet

Simpler experimental setup compared to existing methods

Abstract

We have developed a conceptually new type of ellipsometry which allows the determination of the complex refractive index by simultaneously measuring the unpolarized normal-incidence reflectivity relative to the vacuum and to another reference media. From these two quantities the complex optical response can be directly obtained without Kramers-Kronig transformation. Due to its transparency and large refractive index over a broad range of the spectrum, from the far-infrared to the soft ultraviolet region, diamond can be ideally used as a second reference. The experimental arrangement is rather simple compared to other ellipsometric techniques.