Photoacoustic imaging of biological tissue with intensity-modulated continuous-wave laser.

We build a photoacoustic imaging system using an intensity-modulated continuous-wave laser source, which is an inexpensive, compact, and durable 120-mW laser diode. The goal is to significantly reduce the costs and sizes of photoacoustic imaging systems. By using a bowl-shaped piezoelectric transducer, whose numerical aperture is 0.85 and resonance frequency is 2.45 MHz, we image biological tissues with a lateral resolution of 0.45 mm, an axial resolution of 1 mm, and an SNR as high as 43 dB.