V vase

Optical simulations are conducted using a commercial finite-difference time-domain (FDTD) software package (Lumerical FDTD Solutions)⁷⁵ . For this aim, three dimensional (3D) simulations are employed. A plane-wave excitation in our desire wavelength range (380–800 nm) is used. The boundary conditions in the lateral directions (x and y) are chosen as periodic while these conditions are set as a perfectly matched layer (PML) for the z direction. To measure the normal incidence light reflection from the structure, we used an in-house setup that is made of a halogen lump as the incident light source where this source is integrated into to a microscope to collect the reflected light from the surface. This collected light intensity in the microscope is entered into a spectrometer (Newport OSM2). In all of the measurements, the obtained reflection values are normalized with the reflection data from a thick Al coated sample (which has near 100% reflection in our desired frequency range). Finally, a personal computer (PC) is utilized to extract and monitor the data. In addition, the reflection of the MIMIS samples at different light incident angles is measured utilizing a spectroscopic ellipsometer tool (J. A. Woollam Co. Inc. V-VASE) at two different S and P polarizations. The light angle of incidence is chosen as 30°, 45°, and 60°.

High-quality single-crystals of Sr₃(Ir_1-xRu_x)₂O₇ (x = 0.0, 0.22, 0.34, 0.42, 0.49, 0.65, 0.72, and 0.77) were grown via flux techniques. Dopant content was determined by energy-dispersive X-ray spectroscopy measurements which show a homogeneous Ru distribution within a central value ± 3% (Fig. S2 and Table S1 of the Supplemental Material). The X-ray diffraction measurements reveal no impurity phases within instrument resolution (~ 2–3%) (Fig. S3 of the Supplemental Material). Details of the growth procedure and characterizations were also described elsewhere^{22 (link),23 (link),28 (link)}.
We measured the ab-plane reflectivity spectra R(ω) in the photon energy region between 5 meV and 1 eV using a Fourier transform infrared spectrometer (VERTEX 70v, Bruker) with the in-situ gold overcoating technique^{52 (link)}. We employed spectroscopic ellipsometer (V-VASE and M-2000, J. A. Woollam Co.) to obtain the complex optical conductivity, σ ( ω) =  σ₁(ω) + iσ₂(ω), in the energy range from 0.74 to 5 eV. For the low-energy spectra below 5 meV, R(ω) was extrapolated by using the Hagen-Rubens relation²⁴ . We carried out the Kramers–Kronig analysis of the R(ω) to obtain σ (ω).

Variable angle spectroscopic ellipsometry (J. A. Woollam Co., Inc, V-VASE) was used to determine the thicknesses and optical constants of the Au, Pd, TiO₂ and Al₂O₃ thin films. The reflection and transmission spectra as a function of excitation wavelengths were acquired using the same instrument with a wavelength spectroscopic resolution of 2 nm.