Experimental Design of Near Field Signal Enhancement based on Metal Coating

Near-field signals, such as the localized field strength generated by surface plasmon resonance (SPR), are extensively applied in optics, sensing, and nanotechnology. In the process of near-field imaging, a high-quality probe is used to acquire more accurate sample topography, a higher signal-to-noise ratio, and suppressed background optical information. These signals can be significantly enhanced through the rational design and application of metal coatings. Thus, both signal acquisition capability and probe detection performance are enhanced. In this paper, the transformation of near-field optical microscope and the study of probe coating are included in the research experiment, and the research-oriented experiment on near-field signal enhancement based on metal coating is designed. This experiment is based on the purchased VIT_P type pyramid silicon probe, which is steamed and plated on the tip of the needle, and the modified s-SNOM is used to conduct near-field optical imaging of the standard grating. The effect of gold-plated coating on scattering near-field optical signal is investigated. The experimental results show that the near-field optical signal can be greatly improved by the gold-plated coating on the tip of the needle. This study aims to reveal the enhancement rules of metal coatings on near-field signals and provide new perspectives and experimental foundations for research in the fields of optical sensing and nanophotonics.