Figure 10
From: In vivo sub-femtoliter resolution photoacoustic microscopy with higher frame rates
In vivo 1PA and 2PA images of melanin distribution near the basal layer of the epidermis4.
(a) A 2D 1024 × 1024 pixels image at the depth ~20 μm. Dense mega-pixel number is for sufficiently high sampling frequency for lateral resolution verification. The scale bar is 50 μm. (b) Zoom-in images of the yellow dashed box in (a). The insets are the further enlarged details and only 2PA image provides distinguished melanosomes. The scale bar is 20 μm. (c) The plotted response in (b) gives the upper bound for the lateral resolution. (d) A z projection of 512 × 512 pixels 3D images stack with 52 μm thickness and separation of 4 μm. SG (white arrow), sebaceous gland. The scale bar is 50 μm. In the 1PA case, an out-of-focus black fur of diameter ~60 μm (blue arrow) can be seen. However, this is not the case in 2PA case, where high optical sectioning capability is provided. (e) Zoom-in images of the green and purple dashed boxes of the 2PA case in (d) extended at different depths. Melanosomes (green and purple arrows) emerging in only a single image of a sequence is a proof that the axial resolution of 2PAM is <4 μm. The scale bar is 50 μm.
