  In the paper, combined bimodal microscopic visualization of biological
objects based on reflection-mode optical and photoacoustic measurements was
presented. Gasmicrophone configuration was chosen for the registration of
photothermal response. Precise positioning of the scanning laser beam with
modulated intensity was performed employing acousto-optic deflectors.
Photoacoustic images are shown to give complementary details to the optical
images obtained in the reflected light. Specifically, the photoacoustic imaging
mode allows much better visualization of the features with enhanced heat
localization due to the reduced heat outflow. For example, the application of
the photoacoustic imaging mode was especially successful to visualize
Drosophila fly's micro-hairs. Furthermore, the photoacoustic image quality was
shown to be adjusted through modulation frequency.
