1：Experimental Design and Method Selection:

The study uses RF sputtering to deposit Ni films on fused silica substrates. Optical constants and thickness are determined through multi-angle spectrophotometry and ellipsometry, with validation via X-ray reflectivity (XRR) and X-ray photoelectron spectroscopy (XPS) for composition analysis.

2：Sample Selection and Data Sources:

Two Ni film samples with different thicknesses (3.3 nm and 4.4 nm from sputtering rate) are analyzed. Samples are prepared using a 99.99% pure Ni target in pure Ar gas at room temperature.

3：3 nm and 4 nm from sputtering rate) are analyzed. Samples are prepared using a 99% pure Ni target in pure Ar gas at room temperature. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment includes Perkin Elmer Lambda 950 and Agilent Cary 7000 spectrophotometers for transmittance and reflectance measurements, Horiba Uvisel 2 ellipsometer, KLA-Tencor P-10 profilometer, Vacuum Generator ESCA LAB MKII XPS instrument, and PANalytical Empyrean reflectometer for XRR. Materials include fused silica substrates and a Ni sputtering target.

4：Experimental Procedures and Operational Workflow:

Films are deposited by varying sputtering times. Optical measurements are conducted at multiple angles and wavelengths (200-2000 nm). XPS and XRR measurements are performed to analyze surface composition and thickness, respectively.

5：Data Analysis Methods:

Data are fitted using the Drude model and Lorentzian oscillators for optical constants. Thickness is derived from interference fringes in XRR data. Statistical minimization of mean square error is used in ellipsometry.