Fig. 5. (Color online) Wide-field photothermal microscopy for individual GNP detection. (a) Reflection image of GNR sample. The low signal-to-noise/background ratios hinder the observation of GNRs on the sample. (b) Photothermal reflectance image of the GNR sample area shown in (a) acquired by a 808 nm pump beam with a heating intensity of 1.3 kW·cm2 and modulation frequency of 1 Hz. (c) Color and (d) monochrome dark-field imagea of the GNR sample area shown in (a). The positions of individual GNRs that could not be observed in the reflection image can be determined. The area within the white circle in (a) probable shows a GNR cluster.
© NPSM
