Figure 5
From: In vivo sub-femtoliter resolution photoacoustic microscopy with higher frame rates
Mechanically scanned images of a Rhodamine B processed leaf sample with NA0.3 objective lens (MPLFLN 10×, Olympus) based on (a) demodulation at f, 0.5 MHz, (1PA) and (b) demodulation at 2f, 1 MHz, (2PA). The oval objects were verified as chloroplasts. From the plotted line profile, we derived the upper bound for lateral resolution of 2PAM, with this objective lens, to be 1.38 μm. (c) A polyethylene (PE) tube filled with Rhodamine B solution was imaged with a NA0.9w objective lens (LUMPLFLN 60×, Olympus) in the lateral direction. The interface between the PE tubule wall and the Rhodamine B solution provided the step-edged function. The ESF was well fitted and the derived LSF gave us the lateral resolution. With this objective lens, the lateral resolution of 2PAM was measured as 0.52 μm and R2 value, the goodness of fit, was 0.991.
