Comparison of techniques to characterise the point spread function of an acoustic-resolution photoacoustic microscope

Photoacoustic (PA) point spread function (PSF) of an acoustic-resolution PA microscope (AR-PAM) (easyPAM-400™, Kibero). In the absence of a point absorber, the conventional lateral and axial PSF characterisation approaches of a PAM involve the line spread function (LSF) measurement of an edge and shift-and-sum method, respectively. A comparison is made between these approaches that derive the PSF to that obtained by imaging quasi point targets. The PA lateral and axial resolutions of the PAM derived using the approaches mentioned above were estimated to be 6.59 ± 1.23 μm and 7.6 ± 0.2 μm, respectively. The lateral and axial PSF obtained from the point target were 7.75 ± 0.25 μm and 8.3 ± 0.67 μm, respectively. Comparison indicated that there is good agreement between the approaches that derive the PSF and that obtained by imaging point targets.