Pushing the boundaries of optoacoustic microscopy by total impulse response characterization

摘要

OR-OAM system based on raster scanning an optically focused 532-nm laser excitation across a sample placed in an inverted microscope using galvanometric mirrors. Close-up depiction of the arrangement of the imaging framework and schematic depiction of the generation of SOAPs; arrows indicate degrees of freedom within the OR-OAM system. OR-OAM MAP onto the -plane of a black polystyrene microsphere. OR-OAM MAP of a gold layer at the same axial position. Raw OR-OAM signals and corresponding impulse responses (inset) of the positions in ( ) and ( ) marked with asterisks. Frequency content of the microsphere (black) and the gold layer (gold), and their corresponding frequency responses (inset). Scale bar, 100 µm. AcL acoustic lens, AE active element, AL achromatic doublet lens, AMP low noise amplifier, DAQ data acquisition card, GM galvanometric mirror scanner, GMC GM controller, IM inverted microscope, L plano-convex lens, M dielectric mirror, ND neutral density filter, OL microscope objective lens, PH pinhole, S high-precision motorized stage, SOAP spatially distributed optoacoustic point source, UT ultrasound transducer.