Fig. 3From: Hybrid optical parametrically-oscillating emitter at 1930 nm for volumetric photoacoustic imaging of water contenta PA image of ultrasound gel mixed air bubbles. b The time-domain PA signal of water and its frequency spectrum. c 2-D PA image of the salmon fish belly. d Three-dimensional rendering view of (c). e B-mode image of (c). Scale bars, 500 µm.Back to article page