Photoacoustic microscopy with submicron resolution
We show that it is possible to obtain high optical contrast photoacoustic images of tissue with 0.55 μm transverse resolution. To achieve high sensitivity, we used a high NA (0.85), 125 MHz spherically focused ultrasonic transducer in a confocal arrangement with a high resolution optical objective (NA=0.6). Laser pulses of a few nJ in pulse energy with durations of 1.5 ns at a 20 KHz pulse repetition rate were used to generate photoacoustic waves. Although the penetration depth is limited to hundreds of microns by both optical scattering and ultrasonic absorption, the developed technique can compete with optical microscopy, for example, in quantitative spectral measurements, in microcirculation research, or in nanoparticle detection.
Additional Information© 2010 Society of Photo-Optical Instrumentation Engineers (SPIE). This project is sponsored in part by National Institutes of Health Grant Nos. R01 EB000712, R01 EB008085, R01 CA113453901, U54 CA136398, 5P60 DK02057933 L.W. has a financial interest in Microphotoacoustics, Inc. and Endra, Inc., which, however, did not support this work. Additional information about related works can be found at http://oilab.seas.wustl.edu.
Published - 75640W.pdf