The Raman cross section is the same. The electric field is enhanced by the high radius of curvature of the metal particles. Much like increasing the laser power.

The Raman cross section experiences a boost when analyzing samples in the presence of metal nanoparticles. This enhanced Raman cross section primarily results from mechanisms like chemical and electromagnetic enhancements associated with Surface-Enhanced Raman Spectroscopy (SERS). Nevertheless, the energy of the excitation wavelength and factors like the size, shape, arrangement (hotspots), and the adsorption behavior of analyte molecules on the metal nanoparticles also play significant roles in SERS enhancement. In contrast to conventional Raman scattering, which faces several limitations, including sample concentrations, laser power, wavelength-dependent Raman measurements, fluorescence background interference, and noise-to-signal ratio, SERS significantly mitigates these drawbacks and augments its cross section.