Figure 1

Intensity (a,b) and phase (d,e) distributions in XZ plane for the PT signal obtained with CPTM (a,d) and NPTM (b,e). The sample is a single 20-nm GNP. Scale bar: 500 nm. The cross sections (denoted by the red dashed lines in (a,b,d,e)) of the intensity image (a,b) and phase image (d,e) of the GNP are shown in (c,f) respectively. The axial resolution of CPTM is 703 nm and that for NPTM is worse than 2 μm.