Fig. 1.

(a) Schematic diagram, and (b) Photograph of the PLD-PAT system, (c) Schematic of the OPO-PAT system. Here PLD: Pulsed laser diode, LDU: Laser driver unit, CSP: Circular scanning plate, S: Sample, MPS: Motor pulley system, M: Motor, DAQ: Data Acquisition card, R/A/F: Ultrasound signal receiver, amplifier, and filter, UST: Ultrasound transducer, LP: Long pass filter, GG: Ground glass, P: Antireflection coated right angle prism, L1 and L2: Convex lenses, L3: Concave lens, OPO: Optical parametric oscillator, (d) schematic illustration of laser pulse illumination and A-line signal collection in 3 second continuous scanning setup.