Miniature non-contact photoacoustic probe based on fiber-optic photoacoustic remote sensing microscopy

Photoacoustic (PA) remote sensing (PARS) microscopy, featured by non-contact operation, has shown great potential for PA microscopy (PAM) imaging applications. However, current PARS microscopy systems are mainly based on free-space light, making the imaging head bulky and inconvenient to use. These issues hinder selected applications such as PA endoscopy and handheld PAM. Here, we report a miniature probe capable of non-contact PAM based on PARS microscopy. By utilizing fiber-optic components including a wavelength division multiplexer and an optical circulator, the imaging head can be highly miniaturized with a diameter of ∼3.0mm. Also, since all light is transmitted via fibers, the fiber-optic PARS microscopy system is relatively easy to build and facilitates scanning of the probe. In vivo imaging of a zebrafish larva and imaging of lithium metal batteries are conducted using the probe, showing its good imaging capability.