Research Article

Nanohybrids Near-Field Optical Microscopy: From Image Shift to Biosensor Application

Figure 4

(a) Nanohybrid topographic (left) and optical (right) images. Aggregates of nanoparticles are represented by the randomly distributed white spots. The right-handed legend of the topographic image shows that the thickness of the formed clusters is about 20 nm, corresponding to one layer of nanohybrids. The optical image represents the scattered and fluorescent light emitted from the sample surface and aggregates. (b) Exponential decay curve (in black) of a hybrid nanoparticle aggregate in reflection mode SNOM. Corresponding exponential fitting (in red) is in accordance with decay data. (c) Z topographic (A), phase topographic (B), and an optical image (C) of zoomed part (in a circle) of (a). The blue arrow in the topographic image refers to the region for which profile line and resolution analysis studies are presented in the text (Sections 2.1.3(A) and 2.1.3(B)).