Fig. 2From: Hybrid optical parametrically-oscillating emitter at 1930 nm for volumetric photoacoustic imaging of water contenta Output laser spectrum after the EDFA2 in Fig. 1a; b The relationship between the final output laser pulse energy and the pump power; c 1930-nm pulse train consisted of 1,225 subsequent laser pulses in temporal domain after the TDFA in Fig. 1a; d Pulse peak value histogram of (c).Back to article page