Absolicon is a pioneering solar technology development company specializing in the manufacturing and selling of advanced solar energy systems engineered to generate renewable energy for diverse use. Comprising essential components such as reflectors (mirrors) and a solar receiver tube, these solar energy systems are equipped to efficiently capture and convert solar irradiation into usable thermal energy. As an integral facet of an ongoing research, this project will contribute to optimize the reflection and absorption capacity in receiver tubes of Absolicon's solar collectors. The aim is to investigate optically selective plasmonic coatings intended as an undercoating in the solar selective surfaces. The main coating material that will be used and analysed is gold due to its plasmonic properties and inert nature as well as its low toxicity. The gold will be coated on stainless steel using physical vapor deposition (PVD) and then annealed at mid-to-high temperatures to produce a plasmonic surface. The effect of Au thicknesses, annealing times/temperature and will be investigated to optimize the coating with regards to optical properties based on a systematic method called Design of Experiments (DoE). The goal for the gold coating is to increase the reflectance in the infrared region while generating a plasmonic absorption peak in the visible region (the position and width will be optimized), making it a more beneficial surface to coat a solar selective surface than the original stainless steel (SS). It was found that the size and inter-particle distance of GNPs depend on the temperature and annealing time for different thickness. The surface analysis from SEM-images and AFM-topographs provided that samples with smaller grains are more likely to exhibit significant plasmonic effects compared to larger grains. According to the surface characterization, either thinner gold coating exposed to high temperature for short annealing time or thicker gold coating with longer annealing time provide plasmonic absorption peak in visible light region.