Figure 2.

(a) SERS signal line scanning on a gold nanoparticle-patterned substrate (80 µm, step length 1 µm) with the Raman peak of 612 cm⁻¹ of Rhodamine 6G, and (b) optical micrograph of the line scanning region. SERS were excited by a 638 nm laser with a power of approximately 0.1 mW, and acquisition time of 10 s. The laser spot size was approximately 1 µm in diameter.