Optical resolution photoacoustic imaging of multiple probes via single fiber laser with independently adjustable parameters

Photoacoustic microscopy (PAM) is a promising imaging modality that combines optical and ultrasound imaging. It combines the advantages of high ultrasonic spatial resolution and high optical contrast. When a short laser pulse illuminates the tissue, absorbed light leads to an acoustic emission via thermoelastic expansion. The laser system needs to generate short enough pulses, i.e., several nanoseconds, to create photoacoustic signals with high efficiency and emit wavelengths in the visible range to excite tissue chromophores in their absorption peaks. To increase penetration depth of imaging, it is also desirable to utilize a wavelength in the NIR range, from 600 to 1200 nm, where biological tissues are relatively transparent.