Fig. 4. Optical characterization of the BAMO-Au system. (a) Optical transmission spectra of BAMO-Au thin films as a function of wavelength. (b) Simulation of LSPR and local field enhancement effects using COMSOL Multiphysics® software. (c)–(e) Fitted permittivity for thin films deposited at different temperatures. Films grown at 580 °C and 600 °C display a type I hyperbolic dispersion, and the film grown at 620 °C shows a type II hyperbolic dispersion.