Fig. 2.
(a) Schematic of PAM/OCT system setup. SC, supercontinuum; DM1-DM3, dichroic mirrors; GM, galvanometer; UT, ultrasound transducer; AMP, amplifier; ADC, digitizer; SM, spectrometer; DC, dispersion compensating slab; M1-M2, mirrors; BD, beam dump. The red dashed square is where spectral filtering components are inserted for multispectral PAM measurement, which is further demonstrated in Fig. 4. (b) Representative PA A-line generated by a 1951 USAF resolution test chart. (c) Measurement of axial resolution, sensitivity, and roll-off effect in OCT. (d)–(e) En face and B-scan images of a resolution chart by PAM and OCT, respectively. The positions of B-scan images are indicated by vertical lines in the en face images. Scale bar, 150 μm.