Figure 5:

SERS measurements of BSA solution and numerical calculation of field enhancement: (A) SERS spectra of 10 μmol/L BSA on different substrates measured with a 2 second integration with a 530 nm laser in a micro-Raman system. Prominent Raman peaks are marked in the figure. The solid lines depict the average spectrum, and the shaded region represents the ± standard deviations (SD). (B) Distribution of |E/E₀|⁴ in the XZ plane at 530 nm excitation. All the panels are plotted with the same range of color scale for comparison. The scale bar is 20 nm. The STG configuration shows significant enhancement at the sharp corners, which is due to the lightning rod effect but is absent in our experimental prototype.