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Journal of Biomedical Optics • Open Access

Reflection-mode submicron-resolution in vivo photoacoustic microscopy

Paper Abstract

Submicron-resolution photoacoustic microscopy (PAM) currently exists only in transmission mode, due to the technical difficulties of combining high numerical-aperture (NA) optical illumination with high NA acoustic detection. The lateral resolution of reflection-mode PAM has not reached <2  μm in the visible light range. Here we develop the first reflection-mode submicron-resolution PAM system with a new compact design. By using a parabolic mirror to focus and reflect the photoacoustic waves, sufficient signals were collected for good sensitivity without distorting the optical focusing. By imaging nanospheres and a resolution test chart, the lateral resolution was measured to be ∼ 0.5  μm with an optical wavelength of 532 nm, an optical NA of 0.63. The axial resolution was measured at 15 μm. Here the axial resolution was measured by a different experiment with the lateral resolution measurement. But we didn't describe the details of axial resolution measurement due to space limit. The maximum penetration was measured at ∼ 0.42  mm in optical-scattering soft tissue. As a comparison, both the submicron-resolution PAM and a 2.4 μm-resolution PAM were used to image a mouse ear in vivo with the same optical wavelength and similar pulse energy. Capillaries were resolved better by the submicron-resolution PAM. Therefore, the submicron-resolution PAM is suitable for in vivo high-resolution imaging, or even subcellular imaging, of optical absorption.

Paper Details

Date Published: 23 February 2012
PDF: 4 pages
J. Biomed. Opt. 17(2) 020501 doi: 10.1117/1.JBO.17.2.020501
Published in: Journal of Biomedical Optics Volume 17, Issue 2
Show Author Affiliations
Chi Zhang, Washington Univ. in St. Louis (United States)
Konstantin I. Maslov, Washington Univ. in St. Louis (United States)
Song Hu, Washington Univ. in St. Louis (United States)
Lihong V. Wang, Washington Univ. in St. Louis (United States)
Ruimin Chen, The Univ. of Southern California (United States)
Qifa Zhou, The Univ. of Southern California (United States)
K. Kirk Shung, The Univ. of Southern California (United States)

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