  Nanostructures represent a frontier where meticulous attention to the control
and assessment of structural dimensions becomes a linchpin for their seamless
integration into diverse technological applications. By using integrative and
comprehensive methodical series of studies, we investigate the evolution of the
depolarization factors in the anisotropic Bruggeman effective medium
approximation, that are extremely sensitive to the changes in critical
dimensions of the nanostructure platforms. To this end, we fabricate spatially
coherent highly-ordered slanted nanocolumns from zirconia, silicon, titanium,
and permalloy on silicon substrates with varying column lengths using glancing
angle deposition. In tandem, broad-spectral range Mueller matrix spectroscopic
ellipsometry data, spanning from the near-infrared to the vacuum ultraviolet
(0.72 eV to 6.5 eV), is analyzed with a best-match model approach based on the
anisotropic Bruggeman effective medium theory. We thereby extracted the
anisotropic optical properties including complex dielectric function,
birefringence, and dichroism. Most notably, our research unveils a universal,
material-independent inverse relationship between depolarization factors and
column length. We envision that the presented universal relationship will
permit accurate prediction of optical properties of nanocolumnar thin films
improving their integration and optimization for optoelectronic and photonic
device applications.
