Optical resolution photoacoustic microscopy based on multimode fibers.

Area of Science:

• Biomedical Imaging
• Optical Engineering
• Microscopy

Background:

• Photoacoustic microscopy (PAM) is a multiscale imaging technique.
• Optical-resolution photoacoustic microscopy (OR-PAM) typically uses single-mode (SM) fibers for optical excitation.
• Microelectromechanical systems (MEMS) have improved OR-PAM imaging speed.

Purpose of the Study:

• To report for the first time the use of a multimode (MM) fiber as the optical excitation source for high-resolution OR-PAM.
• To evaluate the feasibility of MM fibers for high-speed, high-resolution in vivo imaging.
• To explore the benefits of MM fibers for simplified optical alignment and high repetition rate light delivery.

Main Methods:

• A high-speed MEMS scanner-based OR-PAM system was developed.
• A multimode (MM) fiber was employed as the optical excitation source.
• The system was combined with mechanical movement for wide-area imaging.

Main Results:

• A lateral resolution of 3.5 µm and axial resolution of 27 µm were achieved.
• Imaging depth of approximately 1.5 mm was demonstrated.
• The use of MM fiber facilitated tight optical focus and easier alignment.

Conclusions:

• Multimode (MM) fibers are effective for high-resolution OR-PAM, offering advantages in optical alignment and speed.
• This approach is beneficial for developing high-resolution photoacoustic endoscopy systems.
• MM fiber-based OR-PAM can be integrated with other optical endoscopic imaging modalities.