Dual-modal imaging with non-contact photoacoustic microscopy and fluorescence microscopy.

Simultaneous imaging of complementary absorption and fluorescence contrasts with high spatial resolution is useful for biomedical studies. However, conventional dual-modal photoacoustic (PA) and fluorescence imaging systems require the use of acoustic coupling media due to the contact operation of PA imaging, which causes issues and complicates the procedure in certain applications such as cell imaging and ophthalmic imaging. We present a novel dual-modal imaging system which combines non-contact PA microscopy (PAM) based on PA remote sensing and fluorescence microscopy (FLM) into one platform. The system enables high lateral resolution of 2 and 2.7 µm for PAM and FLM modes, respectively. In vivo imaging of a zebrafish larva injected with a rhodamine B solution is demonstrated, with PAM visualizing the pigment and FLM revealing the injected rhodamine B.