FDTD software: Lumerical (Ansys, version 2021 R2.3). Structure: SiO2 (Palik) substrate; 35/50/65 nm thickness (DLC) layer with experimentally obtained optical properties of diamond-like carbon and silver nanocomposite (DLC:Ag). DLC:Ag optical properties are averaged result of the layer properties in DLC:Ag nanocomposite obtained by fitting spectroscopic ellipsometry data, which is available here: https://doi.org/10.5281/zenodo.7341684 The file used in the simulations is provided in this data set. Here DLC:Ag is considered as homogeneous materials without separating DLC and Ag phases. Refractive index of the surrounding medium (n): 1.0; 1.1; 1.2; 1.3. Simulation region: from 300 nm below the substrate/DLC:Ag interface to 1.3 µm above it. Mesh override region: from 50 nm below the substrate/DLC:Ag interface to 50 nm above DLC:Ag; 2 nm step size in each direction. Light source: BFAST plane wave light source; 500 nm above the substrate/DLC:Ag interface; 45° angle of incidence (ang); 300 nm – 1000 nm wavelength range; s-polarization (pol). The model structure is not periodic, however, BFAST light source was used for easier comparison with other structures with the same material, which are periodic. Monitor (frequency domain field and power): 2D Z-normal; 1 µm above the substrate/DLC:Ag interface; results are in "_reflection.txt" files. Information in the file name: DLC - thickness of DLC:Ag; pol - polarization; onQ - indicates quartz substrate; ang - angle of incidence; n - refractive index of surrounding medium. Files: (1) "_reflection.txt" - lambda(nm) (first column) - wavelength in nanometers; Y (second column) - T data from the monitor above the structure. (2) "_p0.log" - log file produced by the software while running the simulation. (3) ".fsp" - Lumerical software file containing the simulation project (license required to open these files). (4) "Lumerical_Screenshots.pdf" - shows software screenshots for every object and its every property; red text is added to show which values are different for different simulations. (5) ".jpg" - a preview of data from "_reflection.txt" files. (7) "DLC_Ag_SE_nk_average.txt" - contains DLC:Ag optical properties (first column - wavelength in nanometers; second column - refractive index; third column - extinction coefficient).

The research was carried out under postdoctoral project "Patterned hybrid multilayer films for optical sensors", No. 1.1.1.2/VIAA/4/20/615.