Bessel-beam Grueneisen relaxation photoacoustic microscopy with extended depth of field
The short focal depth of a Gaussian beam limits the volumetric imaging speed of optical resolution photoacoustic microscopy (OR-PAM). A Bessel beam, which is diffraction free, provides a long focal depth, but its side lobes deteriorate image quality when the Bessel beam is directly employed to excite photoacoustic (PA) signals in OR-PAM. We present a nonlinear approach based on the Grueneisen relaxation effect to suppress the side-lobe artifacts in PA imaging. This method extends the focal depth of OR-PAM and speeds up volumetric imaging. We experimentally demonstrated a 1-mm focal depth with a 7-μm lateral resolution and volumetrically imaged a carbon fiber and red blood cell samples.
© 2015 SPIE. Paper 150545R received Aug. 13, 2015; accepted for publication Oct. 7, 2015; published online Nov. 2, 2015. The authors appreciate Prof. James Ballard's help with editing the manuscript. The authors also thank Konstantin Maslov, Lei Li, Jinyang Liang, and Mohammadreza Nasiriavanaki for discussions and technical help in the experiments. This work was supported in part by National Institutes of Health under Grant Nos. DP1 EB016986 (NIH Director's Pioneer Award), R01 CA186567 (NIH Director's Transformative Research Award), and R01 CA159959. L.V.W. has a financial interest in Microphotoacoustics, Inc. and Endra, Inc., which, however, did not support this work.
Published - JBO_20_11_116002.pdf