Figure 5. Methylene blue signal degradation by prolonged laser exposure.

Normalized heights of the 447 cm⁻¹ Raman mode of Ag–MB gathered at 373 K and in inert N₂ atmosphere after exposure to no laser (control, blue diamonds), 532-nm laser (green squares) or 785-nm laser (red triangles) for a given periods of time. The 785-nm laser shows significant signal degradation enhancement compared with the 532 nm and control samples.