Amplitude-masked photoacoustic wavefront shaping: theory and application in flowmetry
Optical diffusion in scattering media prevents focusing beyond shallow depths, causing optical imaging and sensing to suffer from low optical intensities, resulting in low signal-to-noise ratios (SNR). Here, we demonstrate focusing using a fast binary-amplitude digital micromirror device to characterize the transmission modes of the scattering medium. We then identify and selectively illuminate the transmission modes which contribute constructively to the intensity at the optical focus. Applying this method to photoacoustic flowmetry, we increased the optical intensity at the focus six-fold, and showed that the corresponding increase in SNR allows particle flow to be measured.
© 2015 Society of Photo-Optical Instrumentation Engineers. We would like to thank Yong Zhou for experimental assistance and Professor James Ballard for assistance in proofreading the manuscript. This work was sponsored in part by the National Institutes of Health grants DP1 EB016986 (NIH Director's Pioneer Award), R01 CA186567 (NIH Director's Transformative Research Award), R01CA157277, and R01 CA159959. L. V. Wang has a financial interest in Microphotoacoustics, Inc. and Endra, Inc., which, however, did not support this work.
Published - 932310.pdf