Multimodal subcellular imaging with microcavity photoacoustic transducer.

Photoacoustic microscopy (PAM) is dominantly sensitive to the endogenous optical absorption compared with the confocal microscopy which images with scattering photons. PAM has similar structure such as optical transportation system, the optical scanning, and light source with the laser scanning confocal microscopy (LSCM). In order to match the PAM with LSCM, a special design microcavity photoacoustic (PA) transducer with high sensitivity is developed to detect the photoacoustic signals induced by modulated continuous wave (CW) laser. By employing a microcavity PA transducer, a PAM can be integrated with LSCM. Thus a simultaneous multimodal imaging can be obtained with the same laser source and optical system. The lateral resolutions of the PAM and the LSCM are both tested to be better than 1.25 μm. Then subcellular multimodal imaging can be achieved. Images from the two modes are corresponding with each other but functionally complementary. Combining PAM and LSCM provides more comprehensive information for the cytological test. This technique is demonstrated for imaging red-blood cells and meristematic cells.