Bi-modal photothermal/optical microscopy for complementary bio-imaging with high resolution and contrast

Abstract

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.

Application of the Photoacoustic Approach in the Characterization of Nanostructured Materials

“…A combination of PAM with other methods can provide aggregate information about the target sample, complementing different types of imaging [81][82][83]. As scanning modes, it is possible to use various methods for recording the PA response, methods such as optical images for the transmission or reflection of light, the photoelectric (PE) method, etc.…”

“…The use of a dual-mode PAM/optical imaging system has been implemented, for example, for visualizing organic objects, such as the Drosophila fly (see Figure 9) [82]. The obtained PA images complement the images based on the reflected light and reveal the features of the microscopic anatomy of the insect that can be accurately seen only with high-precision and expensive devices such as SEM.…”