Precise spectrophotometric method for semitransparent metallic thin-film index determination using interference enhancement

Journal of the European Optical Society-Rapid Publications

Riley Shurvinton¹  Fabien Lemarchand¹  Julien Lumeau¹  Antonin Moreau¹ 

[1] Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, Marseille, France;

关键词: Spectrophotometry;    Index determination;    Absorbing layers;    Titanium;   

DOI  :  10.1186/s41476-021-00172-9

来源: Springer

【 摘 要 】

A precise spectrophotometric method to determine the refractive index of a semitransparent metallic thin film is presented. This method relies on interference enhancement of the measured spectra, employing an opaque substrate with a dielectric spacer layer beneath the absorbing layer of interest to create interference fringes.The resulting spectral oscillations of the stack are highly sensitive to the properties of the top absorbing layer, allowing precise determination of the refractive index via fitting. The performance of this method is verified using simulations in comparison to the typical method of depositing the absorbing thin film directly onto a transparent substrate. An experimental demonstration is made for titanium thin films over the visible range (370-835 nm). The refractive index of these films is extracted from experimental data using a combination of the Modified Drude and Forouhi-Bloomer models. This method showed high repeatability and precision, and is verified for Ti films between 6-70 nm thickness.

【 授权许可】

CC BY