Focus-free optical-resolution photoacoustic microscopy using an all-fiber Bessel beam generator

摘要

Optical-resolution photoacoustic microscopy (OR-PAM) becomes a premier microscopic imaging tool in biomedicine because it provides agent-free optical absorption information in tissues. By tightly focusing light to a spot, the fine lateral resolution can be achieved in OR-PAM. The focal spot size is typically determined by the numerical aperture of the used objective lens. Here, we demonstrate focus-free OR-PAM using a Bessel beam generator. In this approach, no objective lens is required. We have photoacoustically imaged a carbon fiber with a diameter of ～6 μm, and the measured lateral resolution was ～6-7 μm. Beneficially, the complexities of the existing OR-PAM systems can be greatly relieved.