(a) Schematic of laser-scanning OR-PAM. FLP: fiber launch platform, OF: optical fiber, Col. Lens: collimation lens, Obj. lens: objective lens, UT: ultrasound transducer, and AMP: amplifier. (b) Synchronized signals for line-trigger (green), frame-trigger (blue), fast-axis galvanometer signal (red) from the A/D board, and position signal of the fast-axis galvanometer (magenta).