Related Experiment Video
Updated: May 11, 2025
10:21
Evanescent Field Based Photoacoustics: Optical Property Evaluation at Surfaces
Published on: July 26, 2016
11.6K
Harnessing evanescent photoacoustic waves for multi-domain imaging
Rong Zhou1, Liying Zhang1, Beibei Li1
1State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200241, China.
Photoacoustics
|April 18, 2025
Summary
This study introduces supercritical angle photoacoustic microscopy (SA-PAM), a novel imaging technique that uses evanescent photoacoustic waves to overcome light scattering limitations in biological tissues, enabling new surface imaging capabilities.
Area of Science:
- Biomedical Optics
- Acoustic Imaging
- Microscopy
Background:
- Photoacoustic microscopy (PAM) visualizes optical contrast via photo-generated acoustic signals, overcoming light scattering in tissues.
- Evanescent optical waves have advanced optical microscopy, but their photoacoustic counterparts in PAM are underexplored.
Purpose of the Study:
- To explore the potential of evanescent photoacoustic (PA) waves in photoacoustic microscopy (PAM).
- To develop a novel imaging modality, supercritical angle photoacoustic microscopy (SA-PAM), for enhanced PAM functionalities.
Main Methods:
- Generated and detected evanescent PA waves by placing samples near an interface, directing waves beyond the supercritical angle (SA).
- Analyzed SA-PA signal characteristics, including intensity dependence on source depth and far-field angular patterns.
Main Results:
- Demonstrated the generation and detection of SA-PA waves.
- Observed distinct signal characteristics, such as intensity dependence on source depth and symmetric angular patterns.
- Developed a proof-of-concept for SA-PAM.
Conclusions:
- Evanescent PA waves can be utilized in PAM beyond the supercritical angle.
- SA-PAM enables new functionalities like surface topography reconstruction and edge detection.
- Acoustic near-field exploration is crucial for advancing PA technology.
