Fig. 3.

Spatial resolution and imaging depth test of the OR-PAM system: Measurement of the line spread function (LSF) using the edge of a USAF resolution target. Black (■) dots: photoacoustic signal; red line: edge spread function (ESF); blue line: line spread function (LSF): Inlet shows MAP image of a resolution target (b) photoacoustic axial line of a 6 μm carbon fiber, Inlet shows the B-scan axial image of the carbon fiber (c) Single B-scan PA image of a black needle inserted in a chicken tissue.