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Published October 24, 2014 | Published + Supplemental Material
Journal Article Open

Grueneisen Relaxation Photoacoustic Microscopy


The temperature-dependent property of the Grueneisen parameter has been employed in photoacoustic imaging mainly to measure tissue temperature. Here we explore this property using a different approach and develop Grueneisen relaxation photoacoustic microscopy (GR-PAM), a technique that images nonradiative absorption with confocal optical resolution. GR-PAM sequentially delivers two identical laser pulses with a microsecond-scale time delay. The first laser pulse generates a photoacoustic signal and thermally tags the in-focus absorbers. When the second laser pulse excites the tagged absorbers within the thermal relaxation time, a photoacoustic signal stronger than the first one is produced, owing to the temperature dependence of the Grueneisen parameter. GR-PAM detects the amplitude difference between the two colocated photoacoustic signals, confocally imaging the nonradiative absorption. We greatly improved axial resolution from 45 μm to 2.3 μm and, at the same time, slightly improved lateral resolution from 0.63 μm to 0.41 μm. In addition, the optical sectioning capability facilitates the measurement of the absolute absorption coefficient without fluence calibration.

Additional Information

© 2014 American Physical Society. Received 16 April 2014; published 20 October 2014. The authors appreciate Professor James Ballard's help with editing the manuscript, and thank Dr. Amos Danielli, Junjie Yao, Lijun Ma, Arie Krumholz, and Yan Liu for constructive discussions and experimental assistance. This work was sponsored by NIH Grants No. DP1 EB016986 (NIH Director's Pioneer Award), No. R01 CA186567 (NIH Director's Transformative Research Award), and No. R01 CA159959.

Attached Files

Published - PhysRevLett.113.174301.pdf

Supplemental Material - Supplementary_materials.docx

Supplemental Material - Supplementary_materials.pdf

Supplemental Material - video1.wmv

Supplemental Material - video2.wmv


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August 20, 2023
October 19, 2023