Investigating The Optical Anisotropy of Nanocolumnar Metamaterial Platforms: A Comprehensive Analysis Using Mueller Matrix Spectroscopic Ellipsometry Technique

The nanostructures are at the forefront of advanced technologies such as optoelectronics, quantum information, and biomedical applications, where precise control and assessment of their structural dimensions are crucial for their effective integration into various systems [1,2]. However, accurately determining their critical dimensions and optical properties remains a significant challenge. This study investigates the evolution of depolarization factors in the anisotropic Bruggeman effective medium approximations, revealing their extreme sensitivity to the nanostructure dimensions. Therefore, we fabricate slanted nanocolumnar metamaterial platforms from zirconia, silicon, titanium, and permalloy using glancing angle deposition technique. Utilizing Mueller matrix spectroscopic ellipsometry (covering spectral range from 0.72 eV to 6.5 eV), we extract anisotropic optical properties, including the complex dielectric function and birefringence. Our findings demonstrate a generalized inverse relationship between depolarization factors and column length, providing predictive insights into the optical properties of nanocolumnar thin films [2]. Additionally, we demonstrate their potential in sensing technologies by discussing their performance in nanoparticle detection through cross-polarized spectral color variations.

References:

[1] Carneiro, S. V., et al., Materials Today Nano 22 (2023): 100345.

[2] Kilic, U., et al., Advanced Optical Materials (2024): 2302767.