The article "Probing the Ultimate Limits of Plasmonic Enhancement" by C. Ciraci et al. explores the limitations of field enhancement in plasmonic systems, particularly focusing on the role of nonlocality in the dielectric response of metals. The authors argue that the dominant limiting factor is not resistive loss but the intrinsic nonlocality of the metal's dielectric response. They develop a semi-classical model to describe the electronic response of metals, which places strict bounds on the ultimate field enhancement. The model is validated through experiments involving gold nanoparticles spaced a few angstroms from a gold film, demonstrating that the nonlocal effects significantly reduce the field enhancement compared to predictions from a local model. The study highlights the importance of considering quantum effects and nonlocality in the design and optimization of nanophotonic systems.The article "Probing the Ultimate Limits of Plasmonic Enhancement" by C. Ciraci et al. explores the limitations of field enhancement in plasmonic systems, particularly focusing on the role of nonlocality in the dielectric response of metals. The authors argue that the dominant limiting factor is not resistive loss but the intrinsic nonlocality of the metal's dielectric response. They develop a semi-classical model to describe the electronic response of metals, which places strict bounds on the ultimate field enhancement. The model is validated through experiments involving gold nanoparticles spaced a few angstroms from a gold film, demonstrating that the nonlocal effects significantly reduce the field enhancement compared to predictions from a local model. The study highlights the importance of considering quantum effects and nonlocality in the design and optimization of nanophotonic systems.