Fig. 1: Ultrafast functional photoacoustic microscopy (UFF-PAM) with high imaging speed and wide field of view.

a Schematic of the UFF-PAM system. The 532 nm light path and the 558 nm Raman path are combined for functional imaging. DM dichroic mirror, PD photodiode, UT ultrasound transducer. b The optical spectrum of the Raman path output, and the absorption spectra of oxyhemoglobin (HbO₂) and deoxyhemoglobin (HbR). c The dual-wavelength excitation sequence and the resultant PA signals from HbO₂ and HbR. d The close-up schematic of the ultrasound transducer, the polygon scanner, the start of scan (SOS) detection, and the scanning range. e Scheme of UFF-PAM scanning. Volumetric imaging is achieved by fast polygon scanning along the x axis (fast axis) and stepper motor scanning along the y axis (slow axis). f A representative x–y maximum amplitude projection (MAP) image of a mouse brain vasculature over the entire cortex, acquired by UFF-PAM at 532 nm. g The oxygen saturation of hemoglobin (sO₂) map of the same mouse brain, acquired with dual-wavelength measurements at 532 nm and 558 nm. Scale bar in (f, g), 1 mm